The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2009 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.widget; |
| 18 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 19 | import android.content.Context; |
| 20 | import android.content.res.TypedArray; |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 21 | import android.graphics.Rect; |
| 22 | import android.util.AttributeSet; |
| 23 | import android.view.FocusFinder; |
| 24 | import android.view.KeyEvent; |
| 25 | import android.view.MotionEvent; |
| 26 | import android.view.VelocityTracker; |
| 27 | import android.view.View; |
| 28 | import android.view.ViewConfiguration; |
| 29 | import android.view.ViewGroup; |
| 30 | import android.view.ViewParent; |
| 31 | import android.view.animation.AnimationUtils; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 32 | |
| 33 | import java.util.List; |
| 34 | |
| 35 | /** |
| 36 | * Layout container for a view hierarchy that can be scrolled by the user, |
| 37 | * allowing it to be larger than the physical display. A HorizontalScrollView |
| 38 | * is a {@link FrameLayout}, meaning you should place one child in it |
| 39 | * containing the entire contents to scroll; this child may itself be a layout |
| 40 | * manager with a complex hierarchy of objects. A child that is often used |
| 41 | * is a {@link LinearLayout} in a horizontal orientation, presenting a horizontal |
| 42 | * array of top-level items that the user can scroll through. |
| 43 | * |
| 44 | * <p>You should never use a HorizontalScrollView with a {@link ListView}, since |
| 45 | * ListView takes care of its own scrolling. Most importantly, doing this |
| 46 | * defeats all of the important optimizations in ListView for dealing with |
| 47 | * large lists, since it effectively forces the ListView to display its entire |
| 48 | * list of items to fill up the infinite container supplied by HorizontalScrollView. |
| 49 | * |
| 50 | * <p>The {@link TextView} class also |
| 51 | * takes care of its own scrolling, so does not require a ScrollView, but |
| 52 | * using the two together is possible to achieve the effect of a text view |
| 53 | * within a larger container. |
| 54 | * |
| 55 | * <p>HorizontalScrollView only supports horizontal scrolling. |
| 56 | */ |
| 57 | public class HorizontalScrollView extends FrameLayout { |
| 58 | private static final int ANIMATED_SCROLL_GAP = ScrollView.ANIMATED_SCROLL_GAP; |
| 59 | |
| 60 | private static final float MAX_SCROLL_FACTOR = ScrollView.MAX_SCROLL_FACTOR; |
| 61 | |
| 62 | |
| 63 | private long mLastScroll; |
| 64 | |
| 65 | private final Rect mTempRect = new Rect(); |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 66 | private Scroller mScroller; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 67 | |
| 68 | /** |
| 69 | * Flag to indicate that we are moving focus ourselves. This is so the |
| 70 | * code that watches for focus changes initiated outside this ScrollView |
| 71 | * knows that it does not have to do anything. |
| 72 | */ |
| 73 | private boolean mScrollViewMovedFocus; |
| 74 | |
| 75 | /** |
| 76 | * Position of the last motion event. |
| 77 | */ |
| 78 | private float mLastMotionX; |
| 79 | |
| 80 | /** |
| 81 | * True when the layout has changed but the traversal has not come through yet. |
| 82 | * Ideally the view hierarchy would keep track of this for us. |
| 83 | */ |
| 84 | private boolean mIsLayoutDirty = true; |
| 85 | |
| 86 | /** |
| 87 | * The child to give focus to in the event that a child has requested focus while the |
| 88 | * layout is dirty. This prevents the scroll from being wrong if the child has not been |
| 89 | * laid out before requesting focus. |
| 90 | */ |
| 91 | private View mChildToScrollTo = null; |
| 92 | |
| 93 | /** |
| 94 | * True if the user is currently dragging this ScrollView around. This is |
| 95 | * not the same as 'is being flinged', which can be checked by |
| 96 | * mScroller.isFinished() (flinging begins when the user lifts his finger). |
| 97 | */ |
| 98 | private boolean mIsBeingDragged = false; |
| 99 | |
| 100 | /** |
| 101 | * Determines speed during touch scrolling |
| 102 | */ |
| 103 | private VelocityTracker mVelocityTracker; |
| 104 | |
| 105 | /** |
| 106 | * When set to true, the scroll view measure its child to make it fill the currently |
| 107 | * visible area. |
| 108 | */ |
| 109 | private boolean mFillViewport; |
| 110 | |
| 111 | /** |
| 112 | * Whether arrow scrolling is animated. |
| 113 | */ |
| 114 | private boolean mSmoothScrollingEnabled = true; |
| 115 | |
| 116 | private int mTouchSlop; |
Romain Guy | 4296fc4 | 2009-07-06 11:48:52 -0700 | [diff] [blame] | 117 | private int mMinimumVelocity; |
| 118 | private int mMaximumVelocity; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 119 | |
| 120 | /** |
| 121 | * ID of the active pointer. This is used to retain consistency during |
| 122 | * drags/flings if multiple pointers are used. |
| 123 | */ |
| 124 | private int mActivePointerId = INVALID_POINTER; |
| 125 | |
| 126 | /** |
| 127 | * Sentinel value for no current active pointer. |
| 128 | * Used by {@link #mActivePointerId}. |
| 129 | */ |
| 130 | private static final int INVALID_POINTER = -1; |
| 131 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 132 | public HorizontalScrollView(Context context) { |
| 133 | this(context, null); |
| 134 | } |
| 135 | |
| 136 | public HorizontalScrollView(Context context, AttributeSet attrs) { |
| 137 | this(context, attrs, com.android.internal.R.attr.horizontalScrollViewStyle); |
| 138 | } |
| 139 | |
| 140 | public HorizontalScrollView(Context context, AttributeSet attrs, int defStyle) { |
| 141 | super(context, attrs, defStyle); |
| 142 | initScrollView(); |
| 143 | |
| 144 | TypedArray a = context.obtainStyledAttributes(attrs, |
| 145 | android.R.styleable.HorizontalScrollView, defStyle, 0); |
| 146 | |
| 147 | setFillViewport(a.getBoolean(android.R.styleable.HorizontalScrollView_fillViewport, false)); |
| 148 | |
| 149 | a.recycle(); |
| 150 | } |
| 151 | |
| 152 | @Override |
| 153 | protected float getLeftFadingEdgeStrength() { |
| 154 | if (getChildCount() == 0) { |
| 155 | return 0.0f; |
| 156 | } |
| 157 | |
| 158 | final int length = getHorizontalFadingEdgeLength(); |
| 159 | if (mScrollX < length) { |
| 160 | return mScrollX / (float) length; |
| 161 | } |
| 162 | |
| 163 | return 1.0f; |
| 164 | } |
| 165 | |
| 166 | @Override |
| 167 | protected float getRightFadingEdgeStrength() { |
| 168 | if (getChildCount() == 0) { |
| 169 | return 0.0f; |
| 170 | } |
| 171 | |
| 172 | final int length = getHorizontalFadingEdgeLength(); |
| 173 | final int rightEdge = getWidth() - mPaddingRight; |
| 174 | final int span = getChildAt(0).getRight() - mScrollX - rightEdge; |
| 175 | if (span < length) { |
| 176 | return span / (float) length; |
| 177 | } |
| 178 | |
| 179 | return 1.0f; |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * @return The maximum amount this scroll view will scroll in response to |
| 184 | * an arrow event. |
| 185 | */ |
| 186 | public int getMaxScrollAmount() { |
| 187 | return (int) (MAX_SCROLL_FACTOR * (mRight - mLeft)); |
| 188 | } |
| 189 | |
| 190 | |
| 191 | private void initScrollView() { |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 192 | mScroller = new Scroller(getContext()); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 193 | setFocusable(true); |
| 194 | setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); |
| 195 | setWillNotDraw(false); |
Romain Guy | 4296fc4 | 2009-07-06 11:48:52 -0700 | [diff] [blame] | 196 | final ViewConfiguration configuration = ViewConfiguration.get(mContext); |
| 197 | mTouchSlop = configuration.getScaledTouchSlop(); |
| 198 | mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); |
| 199 | mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 200 | } |
| 201 | |
| 202 | @Override |
| 203 | public void addView(View child) { |
| 204 | if (getChildCount() > 0) { |
| 205 | throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| 206 | } |
| 207 | |
| 208 | super.addView(child); |
| 209 | } |
| 210 | |
| 211 | @Override |
| 212 | public void addView(View child, int index) { |
| 213 | if (getChildCount() > 0) { |
| 214 | throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| 215 | } |
| 216 | |
| 217 | super.addView(child, index); |
| 218 | } |
| 219 | |
| 220 | @Override |
| 221 | public void addView(View child, ViewGroup.LayoutParams params) { |
| 222 | if (getChildCount() > 0) { |
| 223 | throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| 224 | } |
| 225 | |
| 226 | super.addView(child, params); |
| 227 | } |
| 228 | |
| 229 | @Override |
| 230 | public void addView(View child, int index, ViewGroup.LayoutParams params) { |
| 231 | if (getChildCount() > 0) { |
| 232 | throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| 233 | } |
| 234 | |
| 235 | super.addView(child, index, params); |
| 236 | } |
| 237 | |
| 238 | /** |
| 239 | * @return Returns true this HorizontalScrollView can be scrolled |
| 240 | */ |
| 241 | private boolean canScroll() { |
| 242 | View child = getChildAt(0); |
| 243 | if (child != null) { |
| 244 | int childWidth = child.getWidth(); |
| 245 | return getWidth() < childWidth + mPaddingLeft + mPaddingRight ; |
| 246 | } |
| 247 | return false; |
| 248 | } |
| 249 | |
| 250 | /** |
| 251 | * Indicates whether this ScrollView's content is stretched to fill the viewport. |
| 252 | * |
| 253 | * @return True if the content fills the viewport, false otherwise. |
| 254 | */ |
| 255 | public boolean isFillViewport() { |
| 256 | return mFillViewport; |
| 257 | } |
| 258 | |
| 259 | /** |
| 260 | * Indicates this ScrollView whether it should stretch its content width to fill |
| 261 | * the viewport or not. |
| 262 | * |
| 263 | * @param fillViewport True to stretch the content's width to the viewport's |
| 264 | * boundaries, false otherwise. |
| 265 | */ |
| 266 | public void setFillViewport(boolean fillViewport) { |
| 267 | if (fillViewport != mFillViewport) { |
| 268 | mFillViewport = fillViewport; |
| 269 | requestLayout(); |
| 270 | } |
| 271 | } |
| 272 | |
| 273 | /** |
| 274 | * @return Whether arrow scrolling will animate its transition. |
| 275 | */ |
| 276 | public boolean isSmoothScrollingEnabled() { |
| 277 | return mSmoothScrollingEnabled; |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Set whether arrow scrolling will animate its transition. |
| 282 | * @param smoothScrollingEnabled whether arrow scrolling will animate its transition |
| 283 | */ |
| 284 | public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled) { |
| 285 | mSmoothScrollingEnabled = smoothScrollingEnabled; |
| 286 | } |
| 287 | |
| 288 | @Override |
| 289 | protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| 290 | super.onMeasure(widthMeasureSpec, heightMeasureSpec); |
| 291 | |
| 292 | if (!mFillViewport) { |
| 293 | return; |
| 294 | } |
| 295 | |
| 296 | final int widthMode = MeasureSpec.getMode(widthMeasureSpec); |
| 297 | if (widthMode == MeasureSpec.UNSPECIFIED) { |
| 298 | return; |
| 299 | } |
| 300 | |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 301 | if (getChildCount() > 0) { |
| 302 | final View child = getChildAt(0); |
| 303 | int width = getMeasuredWidth(); |
| 304 | if (child.getMeasuredWidth() < width) { |
| 305 | final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| 306 | |
| 307 | int childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec, mPaddingTop |
| 308 | + mPaddingBottom, lp.height); |
| 309 | width -= mPaddingLeft; |
| 310 | width -= mPaddingRight; |
| 311 | int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY); |
| 312 | |
| 313 | child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| 314 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 315 | } |
| 316 | } |
| 317 | |
| 318 | @Override |
| 319 | public boolean dispatchKeyEvent(KeyEvent event) { |
| 320 | // Let the focused view and/or our descendants get the key first |
Romain Guy | 8e618e5 | 2010-03-08 12:18:20 -0800 | [diff] [blame] | 321 | return super.dispatchKeyEvent(event) || executeKeyEvent(event); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 322 | } |
| 323 | |
| 324 | /** |
| 325 | * You can call this function yourself to have the scroll view perform |
| 326 | * scrolling from a key event, just as if the event had been dispatched to |
| 327 | * it by the view hierarchy. |
| 328 | * |
| 329 | * @param event The key event to execute. |
| 330 | * @return Return true if the event was handled, else false. |
| 331 | */ |
| 332 | public boolean executeKeyEvent(KeyEvent event) { |
| 333 | mTempRect.setEmpty(); |
| 334 | |
| 335 | if (!canScroll()) { |
| 336 | if (isFocused()) { |
| 337 | View currentFocused = findFocus(); |
| 338 | if (currentFocused == this) currentFocused = null; |
| 339 | View nextFocused = FocusFinder.getInstance().findNextFocus(this, |
| 340 | currentFocused, View.FOCUS_RIGHT); |
| 341 | return nextFocused != null && nextFocused != this && |
| 342 | nextFocused.requestFocus(View.FOCUS_RIGHT); |
| 343 | } |
| 344 | return false; |
| 345 | } |
| 346 | |
| 347 | boolean handled = false; |
| 348 | if (event.getAction() == KeyEvent.ACTION_DOWN) { |
| 349 | switch (event.getKeyCode()) { |
| 350 | case KeyEvent.KEYCODE_DPAD_LEFT: |
| 351 | if (!event.isAltPressed()) { |
| 352 | handled = arrowScroll(View.FOCUS_LEFT); |
| 353 | } else { |
| 354 | handled = fullScroll(View.FOCUS_LEFT); |
| 355 | } |
| 356 | break; |
| 357 | case KeyEvent.KEYCODE_DPAD_RIGHT: |
| 358 | if (!event.isAltPressed()) { |
| 359 | handled = arrowScroll(View.FOCUS_RIGHT); |
| 360 | } else { |
| 361 | handled = fullScroll(View.FOCUS_RIGHT); |
| 362 | } |
| 363 | break; |
| 364 | case KeyEvent.KEYCODE_SPACE: |
| 365 | pageScroll(event.isShiftPressed() ? View.FOCUS_LEFT : View.FOCUS_RIGHT); |
| 366 | break; |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | return handled; |
| 371 | } |
| 372 | |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 373 | private boolean inChild(int x, int y) { |
| 374 | if (getChildCount() > 0) { |
Adam Powell | 352b978 | 2010-03-24 14:23:43 -0700 | [diff] [blame] | 375 | final int scrollX = mScrollX; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 376 | final View child = getChildAt(0); |
| 377 | return !(y < child.getTop() |
| 378 | || y >= child.getBottom() |
Adam Powell | 352b978 | 2010-03-24 14:23:43 -0700 | [diff] [blame] | 379 | || x < child.getLeft() - scrollX |
| 380 | || x >= child.getRight() - scrollX); |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 381 | } |
| 382 | return false; |
| 383 | } |
| 384 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 385 | @Override |
| 386 | public boolean onInterceptTouchEvent(MotionEvent ev) { |
| 387 | /* |
| 388 | * This method JUST determines whether we want to intercept the motion. |
| 389 | * If we return true, onMotionEvent will be called and we do the actual |
| 390 | * scrolling there. |
| 391 | */ |
| 392 | |
| 393 | /* |
| 394 | * Shortcut the most recurring case: the user is in the dragging |
| 395 | * state and he is moving his finger. We want to intercept this |
| 396 | * motion. |
| 397 | */ |
| 398 | final int action = ev.getAction(); |
| 399 | if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged)) { |
| 400 | return true; |
| 401 | } |
| 402 | |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 403 | switch (action & MotionEvent.ACTION_MASK) { |
| 404 | case MotionEvent.ACTION_MOVE: { |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 405 | /* |
| 406 | * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check |
| 407 | * whether the user has moved far enough from his original down touch. |
| 408 | */ |
| 409 | |
| 410 | /* |
| 411 | * Locally do absolute value. mLastMotionX is set to the x value |
| 412 | * of the down event. |
| 413 | */ |
Adam Powell | 9d0335b | 2010-03-24 13:42:51 -0700 | [diff] [blame] | 414 | final int activePointerId = mActivePointerId; |
| 415 | if (activePointerId == INVALID_POINTER) { |
| 416 | // If we don't have a valid id, the touch down wasn't on content. |
| 417 | break; |
| 418 | } |
| 419 | |
| 420 | final int pointerIndex = ev.findPointerIndex(activePointerId); |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 421 | final float x = ev.getX(pointerIndex); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 422 | final int xDiff = (int) Math.abs(x - mLastMotionX); |
| 423 | if (xDiff > mTouchSlop) { |
| 424 | mIsBeingDragged = true; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 425 | mLastMotionX = x; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 426 | if (mParent != null) mParent.requestDisallowInterceptTouchEvent(true); |
| 427 | } |
| 428 | break; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 429 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 430 | |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 431 | case MotionEvent.ACTION_DOWN: { |
| 432 | final float x = ev.getX(); |
| 433 | if (!inChild((int) x, (int) ev.getY())) { |
| 434 | mIsBeingDragged = false; |
| 435 | break; |
| 436 | } |
| 437 | |
| 438 | /* |
| 439 | * Remember location of down touch. |
| 440 | * ACTION_DOWN always refers to pointer index 0. |
| 441 | */ |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 442 | mLastMotionX = x; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 443 | mActivePointerId = ev.getPointerId(0); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 444 | |
| 445 | /* |
| 446 | * If being flinged and user touches the screen, initiate drag; |
| 447 | * otherwise don't. mScroller.isFinished should be false when |
| 448 | * being flinged. |
| 449 | */ |
| 450 | mIsBeingDragged = !mScroller.isFinished(); |
| 451 | break; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 452 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 453 | |
| 454 | case MotionEvent.ACTION_CANCEL: |
| 455 | case MotionEvent.ACTION_UP: |
| 456 | /* Release the drag */ |
| 457 | mIsBeingDragged = false; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 458 | mActivePointerId = INVALID_POINTER; |
| 459 | break; |
| 460 | case MotionEvent.ACTION_POINTER_UP: |
| 461 | onSecondaryPointerUp(ev); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 462 | break; |
| 463 | } |
| 464 | |
| 465 | /* |
| 466 | * The only time we want to intercept motion events is if we are in the |
| 467 | * drag mode. |
| 468 | */ |
| 469 | return mIsBeingDragged; |
| 470 | } |
| 471 | |
| 472 | @Override |
| 473 | public boolean onTouchEvent(MotionEvent ev) { |
| 474 | |
| 475 | if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { |
| 476 | // Don't handle edge touches immediately -- they may actually belong to one of our |
| 477 | // descendants. |
| 478 | return false; |
| 479 | } |
| 480 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 481 | if (mVelocityTracker == null) { |
| 482 | mVelocityTracker = VelocityTracker.obtain(); |
| 483 | } |
| 484 | mVelocityTracker.addMovement(ev); |
| 485 | |
| 486 | final int action = ev.getAction(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 487 | |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 488 | switch (action & MotionEvent.ACTION_MASK) { |
| 489 | case MotionEvent.ACTION_DOWN: { |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 490 | final float x = ev.getX(); |
| 491 | if (!(mIsBeingDragged = inChild((int) x, (int) ev.getY()))) { |
| 492 | return false; |
| 493 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 494 | |
Adam Powell | 352b978 | 2010-03-24 14:23:43 -0700 | [diff] [blame] | 495 | /* |
| 496 | * If being flinged and user touches, stop the fling. isFinished |
| 497 | * will be false if being flinged. |
| 498 | */ |
| 499 | if (!mScroller.isFinished()) { |
| 500 | mScroller.abortAnimation(); |
| 501 | } |
| 502 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 503 | // Remember where the motion event started |
| 504 | mLastMotionX = x; |
Adam Powell | 352b978 | 2010-03-24 14:23:43 -0700 | [diff] [blame] | 505 | mActivePointerId = ev.getPointerId(0); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 506 | break; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 507 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 508 | case MotionEvent.ACTION_MOVE: |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 509 | if (mIsBeingDragged) { |
| 510 | // Scroll to follow the motion event |
| 511 | final int activePointerIndex = ev.findPointerIndex(mActivePointerId); |
| 512 | final float x = ev.getX(activePointerIndex); |
| 513 | final int deltaX = (int) (mLastMotionX - x); |
| 514 | mLastMotionX = x; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 515 | |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 516 | scrollBy(deltaX, 0); |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 517 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 518 | break; |
| 519 | case MotionEvent.ACTION_UP: |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 520 | if (mIsBeingDragged) { |
| 521 | final VelocityTracker velocityTracker = mVelocityTracker; |
| 522 | velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| 523 | int initialVelocity = (int) velocityTracker.getXVelocity(mActivePointerId); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 524 | |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 525 | if (getChildCount() > 0 && Math.abs(initialVelocity) > mMinimumVelocity) { |
| 526 | fling(-initialVelocity); |
Adam Powell | 17dfce1 | 2010-01-25 18:38:22 -0800 | [diff] [blame] | 527 | } |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 528 | |
| 529 | mActivePointerId = INVALID_POINTER; |
| 530 | mIsBeingDragged = false; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 531 | |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 532 | if (mVelocityTracker != null) { |
| 533 | mVelocityTracker.recycle(); |
| 534 | mVelocityTracker = null; |
| 535 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 536 | } |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 537 | break; |
Adam Powell | 352b978 | 2010-03-24 14:23:43 -0700 | [diff] [blame] | 538 | case MotionEvent.ACTION_CANCEL: |
| 539 | if (mIsBeingDragged && getChildCount() > 0) { |
Adam Powell | 352b978 | 2010-03-24 14:23:43 -0700 | [diff] [blame] | 540 | mActivePointerId = INVALID_POINTER; |
| 541 | mIsBeingDragged = false; |
| 542 | if (mVelocityTracker != null) { |
| 543 | mVelocityTracker.recycle(); |
| 544 | mVelocityTracker = null; |
| 545 | } |
| 546 | } |
| 547 | break; |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 548 | case MotionEvent.ACTION_POINTER_UP: |
| 549 | onSecondaryPointerUp(ev); |
| 550 | break; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 551 | } |
| 552 | return true; |
| 553 | } |
Adam Powell | 0b8bb42 | 2010-02-08 14:30:45 -0800 | [diff] [blame] | 554 | |
Adam Powell | 4cd4770 | 2010-02-25 11:21:14 -0800 | [diff] [blame] | 555 | private void onSecondaryPointerUp(MotionEvent ev) { |
| 556 | final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> |
| 557 | MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
| 558 | final int pointerId = ev.getPointerId(pointerIndex); |
| 559 | if (pointerId == mActivePointerId) { |
| 560 | // This was our active pointer going up. Choose a new |
| 561 | // active pointer and adjust accordingly. |
| 562 | // TODO: Make this decision more intelligent. |
| 563 | final int newPointerIndex = pointerIndex == 0 ? 1 : 0; |
| 564 | mLastMotionX = ev.getX(newPointerIndex); |
| 565 | mActivePointerId = ev.getPointerId(newPointerIndex); |
| 566 | if (mVelocityTracker != null) { |
| 567 | mVelocityTracker.clear(); |
| 568 | } |
| 569 | } |
| 570 | } |
| 571 | |
Adam Powell | 0b8bb42 | 2010-02-08 14:30:45 -0800 | [diff] [blame] | 572 | private int getScrollRange() { |
| 573 | int scrollRange = 0; |
| 574 | if (getChildCount() > 0) { |
| 575 | View child = getChildAt(0); |
| 576 | scrollRange = Math.max(0, |
| 577 | child.getWidth() - getWidth() - mPaddingLeft - mPaddingRight); |
| 578 | } |
| 579 | return scrollRange; |
| 580 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 581 | |
| 582 | /** |
| 583 | * <p> |
| 584 | * Finds the next focusable component that fits in this View's bounds |
| 585 | * (excluding fading edges) pretending that this View's left is located at |
| 586 | * the parameter left. |
| 587 | * </p> |
| 588 | * |
| 589 | * @param leftFocus look for a candidate is the one at the left of the bounds |
| 590 | * if leftFocus is true, or at the right of the bounds if leftFocus |
| 591 | * is false |
| 592 | * @param left the left offset of the bounds in which a focusable must be |
| 593 | * found (the fading edge is assumed to start at this position) |
| 594 | * @param preferredFocusable the View that has highest priority and will be |
| 595 | * returned if it is within my bounds (null is valid) |
| 596 | * @return the next focusable component in the bounds or null if none can be found |
| 597 | */ |
| 598 | private View findFocusableViewInMyBounds(final boolean leftFocus, |
| 599 | final int left, View preferredFocusable) { |
| 600 | /* |
| 601 | * The fading edge's transparent side should be considered for focus |
| 602 | * since it's mostly visible, so we divide the actual fading edge length |
| 603 | * by 2. |
| 604 | */ |
| 605 | final int fadingEdgeLength = getHorizontalFadingEdgeLength() / 2; |
| 606 | final int leftWithoutFadingEdge = left + fadingEdgeLength; |
| 607 | final int rightWithoutFadingEdge = left + getWidth() - fadingEdgeLength; |
| 608 | |
| 609 | if ((preferredFocusable != null) |
| 610 | && (preferredFocusable.getLeft() < rightWithoutFadingEdge) |
| 611 | && (preferredFocusable.getRight() > leftWithoutFadingEdge)) { |
| 612 | return preferredFocusable; |
| 613 | } |
| 614 | |
| 615 | return findFocusableViewInBounds(leftFocus, leftWithoutFadingEdge, |
| 616 | rightWithoutFadingEdge); |
| 617 | } |
| 618 | |
| 619 | /** |
| 620 | * <p> |
| 621 | * Finds the next focusable component that fits in the specified bounds. |
| 622 | * </p> |
| 623 | * |
| 624 | * @param leftFocus look for a candidate is the one at the left of the bounds |
| 625 | * if leftFocus is true, or at the right of the bounds if |
| 626 | * leftFocus is false |
| 627 | * @param left the left offset of the bounds in which a focusable must be |
| 628 | * found |
| 629 | * @param right the right offset of the bounds in which a focusable must |
| 630 | * be found |
| 631 | * @return the next focusable component in the bounds or null if none can |
| 632 | * be found |
| 633 | */ |
| 634 | private View findFocusableViewInBounds(boolean leftFocus, int left, int right) { |
| 635 | |
| 636 | List<View> focusables = getFocusables(View.FOCUS_FORWARD); |
| 637 | View focusCandidate = null; |
| 638 | |
| 639 | /* |
| 640 | * A fully contained focusable is one where its left is below the bound's |
| 641 | * left, and its right is above the bound's right. A partially |
| 642 | * contained focusable is one where some part of it is within the |
| 643 | * bounds, but it also has some part that is not within bounds. A fully contained |
| 644 | * focusable is preferred to a partially contained focusable. |
| 645 | */ |
| 646 | boolean foundFullyContainedFocusable = false; |
| 647 | |
| 648 | int count = focusables.size(); |
| 649 | for (int i = 0; i < count; i++) { |
| 650 | View view = focusables.get(i); |
| 651 | int viewLeft = view.getLeft(); |
| 652 | int viewRight = view.getRight(); |
| 653 | |
| 654 | if (left < viewRight && viewLeft < right) { |
| 655 | /* |
| 656 | * the focusable is in the target area, it is a candidate for |
| 657 | * focusing |
| 658 | */ |
| 659 | |
| 660 | final boolean viewIsFullyContained = (left < viewLeft) && |
| 661 | (viewRight < right); |
| 662 | |
| 663 | if (focusCandidate == null) { |
| 664 | /* No candidate, take this one */ |
| 665 | focusCandidate = view; |
| 666 | foundFullyContainedFocusable = viewIsFullyContained; |
| 667 | } else { |
| 668 | final boolean viewIsCloserToBoundary = |
| 669 | (leftFocus && viewLeft < focusCandidate.getLeft()) || |
| 670 | (!leftFocus && viewRight > focusCandidate.getRight()); |
| 671 | |
| 672 | if (foundFullyContainedFocusable) { |
| 673 | if (viewIsFullyContained && viewIsCloserToBoundary) { |
| 674 | /* |
| 675 | * We're dealing with only fully contained views, so |
| 676 | * it has to be closer to the boundary to beat our |
| 677 | * candidate |
| 678 | */ |
| 679 | focusCandidate = view; |
| 680 | } |
| 681 | } else { |
| 682 | if (viewIsFullyContained) { |
| 683 | /* Any fully contained view beats a partially contained view */ |
| 684 | focusCandidate = view; |
| 685 | foundFullyContainedFocusable = true; |
| 686 | } else if (viewIsCloserToBoundary) { |
| 687 | /* |
| 688 | * Partially contained view beats another partially |
| 689 | * contained view if it's closer |
| 690 | */ |
| 691 | focusCandidate = view; |
| 692 | } |
| 693 | } |
| 694 | } |
| 695 | } |
| 696 | } |
| 697 | |
| 698 | return focusCandidate; |
| 699 | } |
| 700 | |
| 701 | /** |
| 702 | * <p>Handles scrolling in response to a "page up/down" shortcut press. This |
| 703 | * method will scroll the view by one page left or right and give the focus |
| 704 | * to the leftmost/rightmost component in the new visible area. If no |
| 705 | * component is a good candidate for focus, this scrollview reclaims the |
| 706 | * focus.</p> |
| 707 | * |
| 708 | * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} |
| 709 | * to go one page left or {@link android.view.View#FOCUS_RIGHT} |
| 710 | * to go one page right |
| 711 | * @return true if the key event is consumed by this method, false otherwise |
| 712 | */ |
| 713 | public boolean pageScroll(int direction) { |
| 714 | boolean right = direction == View.FOCUS_RIGHT; |
| 715 | int width = getWidth(); |
| 716 | |
| 717 | if (right) { |
| 718 | mTempRect.left = getScrollX() + width; |
| 719 | int count = getChildCount(); |
| 720 | if (count > 0) { |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 721 | View view = getChildAt(0); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 722 | if (mTempRect.left + width > view.getRight()) { |
| 723 | mTempRect.left = view.getRight() - width; |
| 724 | } |
| 725 | } |
| 726 | } else { |
| 727 | mTempRect.left = getScrollX() - width; |
| 728 | if (mTempRect.left < 0) { |
| 729 | mTempRect.left = 0; |
| 730 | } |
| 731 | } |
| 732 | mTempRect.right = mTempRect.left + width; |
| 733 | |
| 734 | return scrollAndFocus(direction, mTempRect.left, mTempRect.right); |
| 735 | } |
| 736 | |
| 737 | /** |
| 738 | * <p>Handles scrolling in response to a "home/end" shortcut press. This |
| 739 | * method will scroll the view to the left or right and give the focus |
| 740 | * to the leftmost/rightmost component in the new visible area. If no |
| 741 | * component is a good candidate for focus, this scrollview reclaims the |
| 742 | * focus.</p> |
| 743 | * |
| 744 | * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} |
| 745 | * to go the left of the view or {@link android.view.View#FOCUS_RIGHT} |
| 746 | * to go the right |
| 747 | * @return true if the key event is consumed by this method, false otherwise |
| 748 | */ |
| 749 | public boolean fullScroll(int direction) { |
| 750 | boolean right = direction == View.FOCUS_RIGHT; |
| 751 | int width = getWidth(); |
| 752 | |
| 753 | mTempRect.left = 0; |
| 754 | mTempRect.right = width; |
| 755 | |
| 756 | if (right) { |
| 757 | int count = getChildCount(); |
| 758 | if (count > 0) { |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 759 | View view = getChildAt(0); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 760 | mTempRect.right = view.getRight(); |
| 761 | mTempRect.left = mTempRect.right - width; |
| 762 | } |
| 763 | } |
| 764 | |
| 765 | return scrollAndFocus(direction, mTempRect.left, mTempRect.right); |
| 766 | } |
| 767 | |
| 768 | /** |
| 769 | * <p>Scrolls the view to make the area defined by <code>left</code> and |
| 770 | * <code>right</code> visible. This method attempts to give the focus |
| 771 | * to a component visible in this area. If no component can be focused in |
| 772 | * the new visible area, the focus is reclaimed by this scrollview.</p> |
| 773 | * |
| 774 | * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} |
| 775 | * to go left {@link android.view.View#FOCUS_RIGHT} to right |
| 776 | * @param left the left offset of the new area to be made visible |
| 777 | * @param right the right offset of the new area to be made visible |
| 778 | * @return true if the key event is consumed by this method, false otherwise |
| 779 | */ |
| 780 | private boolean scrollAndFocus(int direction, int left, int right) { |
| 781 | boolean handled = true; |
| 782 | |
| 783 | int width = getWidth(); |
| 784 | int containerLeft = getScrollX(); |
| 785 | int containerRight = containerLeft + width; |
| 786 | boolean goLeft = direction == View.FOCUS_LEFT; |
| 787 | |
| 788 | View newFocused = findFocusableViewInBounds(goLeft, left, right); |
| 789 | if (newFocused == null) { |
| 790 | newFocused = this; |
| 791 | } |
| 792 | |
| 793 | if (left >= containerLeft && right <= containerRight) { |
| 794 | handled = false; |
| 795 | } else { |
| 796 | int delta = goLeft ? (left - containerLeft) : (right - containerRight); |
| 797 | doScrollX(delta); |
| 798 | } |
| 799 | |
| 800 | if (newFocused != findFocus() && newFocused.requestFocus(direction)) { |
| 801 | mScrollViewMovedFocus = true; |
| 802 | mScrollViewMovedFocus = false; |
| 803 | } |
| 804 | |
| 805 | return handled; |
| 806 | } |
| 807 | |
| 808 | /** |
| 809 | * Handle scrolling in response to a left or right arrow click. |
| 810 | * |
| 811 | * @param direction The direction corresponding to the arrow key that was |
| 812 | * pressed |
| 813 | * @return True if we consumed the event, false otherwise |
| 814 | */ |
| 815 | public boolean arrowScroll(int direction) { |
| 816 | |
| 817 | View currentFocused = findFocus(); |
| 818 | if (currentFocused == this) currentFocused = null; |
| 819 | |
| 820 | View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction); |
| 821 | |
| 822 | final int maxJump = getMaxScrollAmount(); |
| 823 | |
| 824 | if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump)) { |
| 825 | nextFocused.getDrawingRect(mTempRect); |
| 826 | offsetDescendantRectToMyCoords(nextFocused, mTempRect); |
| 827 | int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| 828 | doScrollX(scrollDelta); |
| 829 | nextFocused.requestFocus(direction); |
| 830 | } else { |
| 831 | // no new focus |
| 832 | int scrollDelta = maxJump; |
| 833 | |
| 834 | if (direction == View.FOCUS_LEFT && getScrollX() < scrollDelta) { |
| 835 | scrollDelta = getScrollX(); |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 836 | } else if (direction == View.FOCUS_RIGHT && getChildCount() > 0) { |
| 837 | |
| 838 | int daRight = getChildAt(0).getRight(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 839 | |
| 840 | int screenRight = getScrollX() + getWidth(); |
| 841 | |
| 842 | if (daRight - screenRight < maxJump) { |
| 843 | scrollDelta = daRight - screenRight; |
| 844 | } |
| 845 | } |
| 846 | if (scrollDelta == 0) { |
| 847 | return false; |
| 848 | } |
| 849 | doScrollX(direction == View.FOCUS_RIGHT ? scrollDelta : -scrollDelta); |
| 850 | } |
| 851 | |
| 852 | if (currentFocused != null && currentFocused.isFocused() |
| 853 | && isOffScreen(currentFocused)) { |
| 854 | // previously focused item still has focus and is off screen, give |
| 855 | // it up (take it back to ourselves) |
| 856 | // (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are |
| 857 | // sure to |
| 858 | // get it) |
| 859 | final int descendantFocusability = getDescendantFocusability(); // save |
| 860 | setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS); |
| 861 | requestFocus(); |
| 862 | setDescendantFocusability(descendantFocusability); // restore |
| 863 | } |
| 864 | return true; |
| 865 | } |
| 866 | |
| 867 | /** |
| 868 | * @return whether the descendant of this scroll view is scrolled off |
| 869 | * screen. |
| 870 | */ |
| 871 | private boolean isOffScreen(View descendant) { |
| 872 | return !isWithinDeltaOfScreen(descendant, 0); |
| 873 | } |
| 874 | |
| 875 | /** |
| 876 | * @return whether the descendant of this scroll view is within delta |
| 877 | * pixels of being on the screen. |
| 878 | */ |
| 879 | private boolean isWithinDeltaOfScreen(View descendant, int delta) { |
| 880 | descendant.getDrawingRect(mTempRect); |
| 881 | offsetDescendantRectToMyCoords(descendant, mTempRect); |
| 882 | |
| 883 | return (mTempRect.right + delta) >= getScrollX() |
| 884 | && (mTempRect.left - delta) <= (getScrollX() + getWidth()); |
| 885 | } |
| 886 | |
| 887 | /** |
| 888 | * Smooth scroll by a X delta |
| 889 | * |
| 890 | * @param delta the number of pixels to scroll by on the X axis |
| 891 | */ |
| 892 | private void doScrollX(int delta) { |
| 893 | if (delta != 0) { |
| 894 | if (mSmoothScrollingEnabled) { |
| 895 | smoothScrollBy(delta, 0); |
| 896 | } else { |
| 897 | scrollBy(delta, 0); |
| 898 | } |
| 899 | } |
| 900 | } |
| 901 | |
| 902 | /** |
| 903 | * Like {@link View#scrollBy}, but scroll smoothly instead of immediately. |
| 904 | * |
| 905 | * @param dx the number of pixels to scroll by on the X axis |
| 906 | * @param dy the number of pixels to scroll by on the Y axis |
| 907 | */ |
| 908 | public final void smoothScrollBy(int dx, int dy) { |
Adam Powell | 3fc3737 | 2010-01-28 13:52:24 -0800 | [diff] [blame] | 909 | if (getChildCount() == 0) { |
| 910 | // Nothing to do. |
| 911 | return; |
| 912 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 913 | long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll; |
| 914 | if (duration > ANIMATED_SCROLL_GAP) { |
Adam Powell | f544605 | 2010-01-28 17:24:56 -0800 | [diff] [blame] | 915 | final int width = getWidth() - mPaddingRight - mPaddingLeft; |
| 916 | final int right = getChildAt(0).getWidth(); |
| 917 | final int maxX = Math.max(0, right - width); |
| 918 | final int scrollX = mScrollX; |
| 919 | dx = Math.max(0, Math.min(scrollX + dx, maxX)) - scrollX; |
| 920 | |
| 921 | mScroller.startScroll(scrollX, mScrollY, dx, 0); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 922 | invalidate(); |
| 923 | } else { |
| 924 | if (!mScroller.isFinished()) { |
| 925 | mScroller.abortAnimation(); |
| 926 | } |
| 927 | scrollBy(dx, dy); |
| 928 | } |
| 929 | mLastScroll = AnimationUtils.currentAnimationTimeMillis(); |
| 930 | } |
| 931 | |
| 932 | /** |
| 933 | * Like {@link #scrollTo}, but scroll smoothly instead of immediately. |
| 934 | * |
| 935 | * @param x the position where to scroll on the X axis |
| 936 | * @param y the position where to scroll on the Y axis |
| 937 | */ |
| 938 | public final void smoothScrollTo(int x, int y) { |
| 939 | smoothScrollBy(x - mScrollX, y - mScrollY); |
| 940 | } |
| 941 | |
| 942 | /** |
| 943 | * <p>The scroll range of a scroll view is the overall width of all of its |
| 944 | * children.</p> |
| 945 | */ |
| 946 | @Override |
| 947 | protected int computeHorizontalScrollRange() { |
Adam Powell | a2f9101 | 2010-02-16 12:26:33 -0800 | [diff] [blame] | 948 | final int count = getChildCount(); |
| 949 | final int contentWidth = getWidth() - mPaddingLeft - mPaddingRight; |
Adam Powell | 0b8bb42 | 2010-02-08 14:30:45 -0800 | [diff] [blame] | 950 | if (count == 0) { |
Adam Powell | a2f9101 | 2010-02-16 12:26:33 -0800 | [diff] [blame] | 951 | return contentWidth; |
Adam Powell | 0b8bb42 | 2010-02-08 14:30:45 -0800 | [diff] [blame] | 952 | } |
| 953 | |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 954 | return getChildAt(0).getRight(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 955 | } |
Adam Powell | 0b8bb42 | 2010-02-08 14:30:45 -0800 | [diff] [blame] | 956 | |
| 957 | @Override |
| 958 | protected int computeHorizontalScrollOffset() { |
| 959 | return Math.max(0, super.computeHorizontalScrollOffset()); |
| 960 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 961 | |
| 962 | @Override |
| 963 | protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) { |
| 964 | ViewGroup.LayoutParams lp = child.getLayoutParams(); |
| 965 | |
| 966 | int childWidthMeasureSpec; |
| 967 | int childHeightMeasureSpec; |
| 968 | |
| 969 | childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, mPaddingTop |
| 970 | + mPaddingBottom, lp.height); |
| 971 | |
| 972 | childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); |
| 973 | |
| 974 | child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| 975 | } |
| 976 | |
| 977 | @Override |
| 978 | protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed, |
| 979 | int parentHeightMeasureSpec, int heightUsed) { |
| 980 | final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); |
| 981 | |
| 982 | final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, |
| 983 | mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin |
| 984 | + heightUsed, lp.height); |
| 985 | final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec( |
| 986 | lp.leftMargin + lp.rightMargin, MeasureSpec.UNSPECIFIED); |
| 987 | |
| 988 | child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| 989 | } |
| 990 | |
| 991 | @Override |
| 992 | public void computeScroll() { |
| 993 | if (mScroller.computeScrollOffset()) { |
| 994 | // This is called at drawing time by ViewGroup. We don't want to |
| 995 | // re-show the scrollbars at this point, which scrollTo will do, |
| 996 | // so we replicate most of scrollTo here. |
| 997 | // |
| 998 | // It's a little odd to call onScrollChanged from inside the drawing. |
| 999 | // |
| 1000 | // It is, except when you remember that computeScroll() is used to |
| 1001 | // animate scrolling. So unless we want to defer the onScrollChanged() |
| 1002 | // until the end of the animated scrolling, we don't really have a |
| 1003 | // choice here. |
| 1004 | // |
| 1005 | // I agree. The alternative, which I think would be worse, is to post |
| 1006 | // something and tell the subclasses later. This is bad because there |
| 1007 | // will be a window where mScrollX/Y is different from what the app |
| 1008 | // thinks it is. |
| 1009 | // |
| 1010 | int oldX = mScrollX; |
| 1011 | int oldY = mScrollY; |
| 1012 | int x = mScroller.getCurrX(); |
| 1013 | int y = mScroller.getCurrY(); |
Adam Powell | 17dfce1 | 2010-01-25 18:38:22 -0800 | [diff] [blame] | 1014 | |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 1015 | if (getChildCount() > 0) { |
| 1016 | View child = getChildAt(0); |
| 1017 | x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth()); |
| 1018 | y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight()); |
| 1019 | if (x != oldX || y != oldY) { |
| 1020 | mScrollX = x; |
| 1021 | mScrollY = y; |
| 1022 | onScrollChanged(x, y, oldX, oldY); |
| 1023 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1024 | } |
Adam Powell | a0d645cb | 2010-03-31 17:27:49 -0700 | [diff] [blame^] | 1025 | awakenScrollBars(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1026 | |
| 1027 | // Keep on drawing until the animation has finished. |
| 1028 | postInvalidate(); |
| 1029 | } |
| 1030 | } |
| 1031 | |
| 1032 | /** |
| 1033 | * Scrolls the view to the given child. |
| 1034 | * |
| 1035 | * @param child the View to scroll to |
| 1036 | */ |
| 1037 | private void scrollToChild(View child) { |
| 1038 | child.getDrawingRect(mTempRect); |
| 1039 | |
| 1040 | /* Offset from child's local coordinates to ScrollView coordinates */ |
| 1041 | offsetDescendantRectToMyCoords(child, mTempRect); |
| 1042 | |
| 1043 | int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| 1044 | |
| 1045 | if (scrollDelta != 0) { |
| 1046 | scrollBy(scrollDelta, 0); |
| 1047 | } |
| 1048 | } |
| 1049 | |
| 1050 | /** |
| 1051 | * If rect is off screen, scroll just enough to get it (or at least the |
| 1052 | * first screen size chunk of it) on screen. |
| 1053 | * |
| 1054 | * @param rect The rectangle. |
| 1055 | * @param immediate True to scroll immediately without animation |
| 1056 | * @return true if scrolling was performed |
| 1057 | */ |
| 1058 | private boolean scrollToChildRect(Rect rect, boolean immediate) { |
| 1059 | final int delta = computeScrollDeltaToGetChildRectOnScreen(rect); |
| 1060 | final boolean scroll = delta != 0; |
| 1061 | if (scroll) { |
| 1062 | if (immediate) { |
| 1063 | scrollBy(delta, 0); |
| 1064 | } else { |
| 1065 | smoothScrollBy(delta, 0); |
| 1066 | } |
| 1067 | } |
| 1068 | return scroll; |
| 1069 | } |
| 1070 | |
| 1071 | /** |
| 1072 | * Compute the amount to scroll in the X direction in order to get |
| 1073 | * a rectangle completely on the screen (or, if taller than the screen, |
| 1074 | * at least the first screen size chunk of it). |
| 1075 | * |
| 1076 | * @param rect The rect. |
| 1077 | * @return The scroll delta. |
| 1078 | */ |
| 1079 | protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) { |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 1080 | if (getChildCount() == 0) return 0; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1081 | |
| 1082 | int width = getWidth(); |
| 1083 | int screenLeft = getScrollX(); |
| 1084 | int screenRight = screenLeft + width; |
| 1085 | |
| 1086 | int fadingEdge = getHorizontalFadingEdgeLength(); |
| 1087 | |
| 1088 | // leave room for left fading edge as long as rect isn't at very left |
| 1089 | if (rect.left > 0) { |
| 1090 | screenLeft += fadingEdge; |
| 1091 | } |
| 1092 | |
| 1093 | // leave room for right fading edge as long as rect isn't at very right |
| 1094 | if (rect.right < getChildAt(0).getWidth()) { |
| 1095 | screenRight -= fadingEdge; |
| 1096 | } |
| 1097 | |
| 1098 | int scrollXDelta = 0; |
| 1099 | |
| 1100 | if (rect.right > screenRight && rect.left > screenLeft) { |
| 1101 | // need to move right to get it in view: move right just enough so |
| 1102 | // that the entire rectangle is in view (or at least the first |
| 1103 | // screen size chunk). |
| 1104 | |
| 1105 | if (rect.width() > width) { |
| 1106 | // just enough to get screen size chunk on |
| 1107 | scrollXDelta += (rect.left - screenLeft); |
| 1108 | } else { |
| 1109 | // get entire rect at right of screen |
| 1110 | scrollXDelta += (rect.right - screenRight); |
| 1111 | } |
| 1112 | |
| 1113 | // make sure we aren't scrolling beyond the end of our content |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 1114 | int right = getChildAt(0).getRight(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1115 | int distanceToRight = right - screenRight; |
| 1116 | scrollXDelta = Math.min(scrollXDelta, distanceToRight); |
| 1117 | |
| 1118 | } else if (rect.left < screenLeft && rect.right < screenRight) { |
| 1119 | // need to move right to get it in view: move right just enough so that |
| 1120 | // entire rectangle is in view (or at least the first screen |
| 1121 | // size chunk of it). |
| 1122 | |
| 1123 | if (rect.width() > width) { |
| 1124 | // screen size chunk |
| 1125 | scrollXDelta -= (screenRight - rect.right); |
| 1126 | } else { |
| 1127 | // entire rect at left |
| 1128 | scrollXDelta -= (screenLeft - rect.left); |
| 1129 | } |
| 1130 | |
| 1131 | // make sure we aren't scrolling any further than the left our content |
| 1132 | scrollXDelta = Math.max(scrollXDelta, -getScrollX()); |
| 1133 | } |
| 1134 | return scrollXDelta; |
| 1135 | } |
| 1136 | |
| 1137 | @Override |
| 1138 | public void requestChildFocus(View child, View focused) { |
| 1139 | if (!mScrollViewMovedFocus) { |
| 1140 | if (!mIsLayoutDirty) { |
| 1141 | scrollToChild(focused); |
| 1142 | } else { |
| 1143 | // The child may not be laid out yet, we can't compute the scroll yet |
| 1144 | mChildToScrollTo = focused; |
| 1145 | } |
| 1146 | } |
| 1147 | super.requestChildFocus(child, focused); |
| 1148 | } |
| 1149 | |
| 1150 | |
| 1151 | /** |
| 1152 | * When looking for focus in children of a scroll view, need to be a little |
| 1153 | * more careful not to give focus to something that is scrolled off screen. |
| 1154 | * |
| 1155 | * This is more expensive than the default {@link android.view.ViewGroup} |
| 1156 | * implementation, otherwise this behavior might have been made the default. |
| 1157 | */ |
| 1158 | @Override |
| 1159 | protected boolean onRequestFocusInDescendants(int direction, |
| 1160 | Rect previouslyFocusedRect) { |
| 1161 | |
| 1162 | // convert from forward / backward notation to up / down / left / right |
| 1163 | // (ugh). |
| 1164 | if (direction == View.FOCUS_FORWARD) { |
| 1165 | direction = View.FOCUS_RIGHT; |
| 1166 | } else if (direction == View.FOCUS_BACKWARD) { |
| 1167 | direction = View.FOCUS_LEFT; |
| 1168 | } |
| 1169 | |
| 1170 | final View nextFocus = previouslyFocusedRect == null ? |
| 1171 | FocusFinder.getInstance().findNextFocus(this, null, direction) : |
| 1172 | FocusFinder.getInstance().findNextFocusFromRect(this, |
| 1173 | previouslyFocusedRect, direction); |
| 1174 | |
| 1175 | if (nextFocus == null) { |
| 1176 | return false; |
| 1177 | } |
| 1178 | |
| 1179 | if (isOffScreen(nextFocus)) { |
| 1180 | return false; |
| 1181 | } |
| 1182 | |
| 1183 | return nextFocus.requestFocus(direction, previouslyFocusedRect); |
| 1184 | } |
| 1185 | |
| 1186 | @Override |
| 1187 | public boolean requestChildRectangleOnScreen(View child, Rect rectangle, |
| 1188 | boolean immediate) { |
| 1189 | // offset into coordinate space of this scroll view |
| 1190 | rectangle.offset(child.getLeft() - child.getScrollX(), |
| 1191 | child.getTop() - child.getScrollY()); |
| 1192 | |
| 1193 | return scrollToChildRect(rectangle, immediate); |
| 1194 | } |
| 1195 | |
| 1196 | @Override |
| 1197 | public void requestLayout() { |
| 1198 | mIsLayoutDirty = true; |
| 1199 | super.requestLayout(); |
| 1200 | } |
| 1201 | |
| 1202 | @Override |
| 1203 | protected void onLayout(boolean changed, int l, int t, int r, int b) { |
| 1204 | super.onLayout(changed, l, t, r, b); |
| 1205 | mIsLayoutDirty = false; |
| 1206 | // Give a child focus if it needs it |
| 1207 | if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) { |
| 1208 | scrollToChild(mChildToScrollTo); |
| 1209 | } |
| 1210 | mChildToScrollTo = null; |
| 1211 | |
| 1212 | // Calling this with the present values causes it to re-clam them |
| 1213 | scrollTo(mScrollX, mScrollY); |
| 1214 | } |
| 1215 | |
| 1216 | @Override |
| 1217 | protected void onSizeChanged(int w, int h, int oldw, int oldh) { |
| 1218 | super.onSizeChanged(w, h, oldw, oldh); |
| 1219 | |
| 1220 | View currentFocused = findFocus(); |
| 1221 | if (null == currentFocused || this == currentFocused) |
| 1222 | return; |
| 1223 | |
| 1224 | final int maxJump = mRight - mLeft; |
| 1225 | |
| 1226 | if (isWithinDeltaOfScreen(currentFocused, maxJump)) { |
| 1227 | currentFocused.getDrawingRect(mTempRect); |
| 1228 | offsetDescendantRectToMyCoords(currentFocused, mTempRect); |
| 1229 | int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| 1230 | doScrollX(scrollDelta); |
| 1231 | } |
| 1232 | } |
| 1233 | |
| 1234 | /** |
| 1235 | * Return true if child is an descendant of parent, (or equal to the parent). |
| 1236 | */ |
| 1237 | private boolean isViewDescendantOf(View child, View parent) { |
| 1238 | if (child == parent) { |
| 1239 | return true; |
| 1240 | } |
| 1241 | |
| 1242 | final ViewParent theParent = child.getParent(); |
| 1243 | return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent); |
| 1244 | } |
| 1245 | |
| 1246 | /** |
| 1247 | * Fling the scroll view |
| 1248 | * |
| 1249 | * @param velocityX The initial velocity in the X direction. Positive |
| 1250 | * numbers mean that the finger/curor is moving down the screen, |
| 1251 | * which means we want to scroll towards the left. |
| 1252 | */ |
| 1253 | public void fling(int velocityX) { |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 1254 | if (getChildCount() > 0) { |
| 1255 | int width = getWidth() - mPaddingRight - mPaddingLeft; |
| 1256 | int right = getChildAt(0).getWidth(); |
| 1257 | |
Adam Powell | 17dfce1 | 2010-01-25 18:38:22 -0800 | [diff] [blame] | 1258 | mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0, |
Adam Powell | 9d32d24 | 2010-03-29 16:02:07 -0700 | [diff] [blame] | 1259 | Math.max(0, right - width), 0, 0); |
Romain Guy | ef0e9ae | 2009-07-10 14:11:26 -0700 | [diff] [blame] | 1260 | |
| 1261 | final boolean movingRight = velocityX > 0; |
| 1262 | |
| 1263 | View newFocused = findFocusableViewInMyBounds(movingRight, |
| 1264 | mScroller.getFinalX(), findFocus()); |
| 1265 | |
| 1266 | if (newFocused == null) { |
| 1267 | newFocused = this; |
| 1268 | } |
| 1269 | |
| 1270 | if (newFocused != findFocus() |
| 1271 | && newFocused.requestFocus(movingRight ? View.FOCUS_RIGHT : View.FOCUS_LEFT)) { |
| 1272 | mScrollViewMovedFocus = true; |
| 1273 | mScrollViewMovedFocus = false; |
| 1274 | } |
| 1275 | |
| 1276 | invalidate(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1277 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1278 | } |
| 1279 | |
| 1280 | /** |
| 1281 | * {@inheritDoc} |
| 1282 | * |
| 1283 | * <p>This version also clamps the scrolling to the bounds of our child. |
| 1284 | */ |
| 1285 | public void scrollTo(int x, int y) { |
| 1286 | // we rely on the fact the View.scrollBy calls scrollTo. |
| 1287 | if (getChildCount() > 0) { |
| 1288 | View child = getChildAt(0); |
| 1289 | x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth()); |
| 1290 | y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight()); |
| 1291 | if (x != mScrollX || y != mScrollY) { |
| 1292 | super.scrollTo(x, y); |
| 1293 | } |
| 1294 | } |
| 1295 | } |
| 1296 | |
| 1297 | private int clamp(int n, int my, int child) { |
| 1298 | if (my >= child || n < 0) { |
| 1299 | return 0; |
| 1300 | } |
| 1301 | if ((my + n) > child) { |
| 1302 | return child - my; |
| 1303 | } |
| 1304 | return n; |
| 1305 | } |
| 1306 | } |