| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.systemui.recents.views; |
| |
| import android.animation.Animator; |
| import android.animation.AnimatorListenerAdapter; |
| import android.animation.ObjectAnimator; |
| import android.animation.ValueAnimator; |
| import android.animation.ValueAnimator.AnimatorUpdateListener; |
| import android.annotation.TargetApi; |
| import android.os.Build; |
| import android.util.DisplayMetrics; |
| import android.view.MotionEvent; |
| import android.view.VelocityTracker; |
| import android.view.View; |
| import android.view.animation.LinearInterpolator; |
| import com.android.systemui.recents.RecentsConfiguration; |
| |
| /** |
| * This class facilitates swipe to dismiss. It defines an interface to be implemented by the |
| * by the class hosting the views that need to swiped, and, using this interface, handles touch |
| * events and translates / fades / animates the view as it is dismissed. |
| */ |
| public class SwipeHelper { |
| static final String TAG = "SwipeHelper"; |
| private static final boolean SLOW_ANIMATIONS = false; // DEBUG; |
| private static final boolean CONSTRAIN_SWIPE = true; |
| private static final boolean FADE_OUT_DURING_SWIPE = true; |
| private static final boolean DISMISS_IF_SWIPED_FAR_ENOUGH = true; |
| |
| public static final int X = 0; |
| public static final int Y = 1; |
| |
| private static LinearInterpolator sLinearInterpolator = new LinearInterpolator(); |
| |
| private float SWIPE_ESCAPE_VELOCITY = 100f; // dp/sec |
| private int DEFAULT_ESCAPE_ANIMATION_DURATION = 75; // ms |
| private int MAX_ESCAPE_ANIMATION_DURATION = 150; // ms |
| private int MAX_DISMISS_VELOCITY = 2000; // dp/sec |
| private static final int SNAP_ANIM_LEN = SLOW_ANIMATIONS ? 1000 : 250; // ms |
| |
| public static float ALPHA_FADE_START = 0.15f; // fraction of thumbnail width |
| // where fade starts |
| static final float ALPHA_FADE_END = 0.65f; // fraction of thumbnail width |
| // beyond which alpha->0 |
| private float mMinAlpha = 0f; |
| |
| private float mPagingTouchSlop; |
| Callback mCallback; |
| private int mSwipeDirection; |
| private VelocityTracker mVelocityTracker; |
| |
| private float mInitialTouchPos; |
| private boolean mDragging; |
| |
| private View mCurrView; |
| private boolean mCanCurrViewBeDimissed; |
| private float mDensityScale; |
| |
| public boolean mAllowSwipeTowardsStart = true; |
| public boolean mAllowSwipeTowardsEnd = true; |
| private boolean mRtl; |
| |
| public SwipeHelper(int swipeDirection, Callback callback, float densityScale, |
| float pagingTouchSlop) { |
| mCallback = callback; |
| mSwipeDirection = swipeDirection; |
| mVelocityTracker = VelocityTracker.obtain(); |
| mDensityScale = densityScale; |
| mPagingTouchSlop = pagingTouchSlop; |
| } |
| |
| public void setDensityScale(float densityScale) { |
| mDensityScale = densityScale; |
| } |
| |
| public void setPagingTouchSlop(float pagingTouchSlop) { |
| mPagingTouchSlop = pagingTouchSlop; |
| } |
| |
| public void cancelOngoingDrag() { |
| if (mDragging) { |
| if (mCurrView != null) { |
| mCallback.onDragCancelled(mCurrView); |
| setTranslation(mCurrView, 0); |
| mCallback.onSnapBackCompleted(mCurrView); |
| mCurrView = null; |
| } |
| mDragging = false; |
| } |
| } |
| |
| public void resetTranslation(View v) { |
| setTranslation(v, 0); |
| } |
| |
| private float getPos(MotionEvent ev) { |
| return mSwipeDirection == X ? ev.getX() : ev.getY(); |
| } |
| |
| private float getTranslation(View v) { |
| return mSwipeDirection == X ? v.getTranslationX() : v.getTranslationY(); |
| } |
| |
| private float getVelocity(VelocityTracker vt) { |
| return mSwipeDirection == X ? vt.getXVelocity() : |
| vt.getYVelocity(); |
| } |
| |
| private ObjectAnimator createTranslationAnimation(View v, float newPos) { |
| ObjectAnimator anim = ObjectAnimator.ofFloat(v, |
| mSwipeDirection == X ? View.TRANSLATION_X : View.TRANSLATION_Y, newPos); |
| return anim; |
| } |
| |
| private float getPerpendicularVelocity(VelocityTracker vt) { |
| return mSwipeDirection == X ? vt.getYVelocity() : |
| vt.getXVelocity(); |
| } |
| |
| private void setTranslation(View v, float translate) { |
| if (mSwipeDirection == X) { |
| v.setTranslationX(translate); |
| } else { |
| v.setTranslationY(translate); |
| } |
| } |
| |
| private float getSize(View v) { |
| final DisplayMetrics dm = v.getContext().getResources().getDisplayMetrics(); |
| return mSwipeDirection == X ? dm.widthPixels : dm.heightPixels; |
| } |
| |
| public void setMinAlpha(float minAlpha) { |
| mMinAlpha = minAlpha; |
| } |
| |
| float getAlphaForOffset(View view) { |
| float viewSize = getSize(view); |
| final float fadeSize = ALPHA_FADE_END * viewSize; |
| float result = 1.0f; |
| float pos = getTranslation(view); |
| if (pos >= viewSize * ALPHA_FADE_START) { |
| result = 1.0f - (pos - viewSize * ALPHA_FADE_START) / fadeSize; |
| } else if (pos < viewSize * (1.0f - ALPHA_FADE_START)) { |
| result = 1.0f + (viewSize * ALPHA_FADE_START + pos) / fadeSize; |
| } |
| result = Math.min(result, 1.0f); |
| result = Math.max(result, 0f); |
| return Math.max(mMinAlpha, result); |
| } |
| |
| /** |
| * Determines whether the given view has RTL layout. |
| */ |
| @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1) |
| public static boolean isLayoutRtl(View view) { |
| if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) { |
| return View.LAYOUT_DIRECTION_RTL == view.getLayoutDirection(); |
| } else { |
| return false; |
| } |
| } |
| |
| public boolean onInterceptTouchEvent(MotionEvent ev) { |
| final int action = ev.getAction(); |
| |
| switch (action) { |
| case MotionEvent.ACTION_DOWN: |
| mDragging = false; |
| mCurrView = mCallback.getChildAtPosition(ev); |
| mVelocityTracker.clear(); |
| if (mCurrView != null) { |
| mRtl = isLayoutRtl(mCurrView); |
| mCanCurrViewBeDimissed = mCallback.canChildBeDismissed(mCurrView); |
| mVelocityTracker.addMovement(ev); |
| mInitialTouchPos = getPos(ev); |
| } else { |
| mCanCurrViewBeDimissed = false; |
| } |
| break; |
| case MotionEvent.ACTION_MOVE: |
| if (mCurrView != null) { |
| mVelocityTracker.addMovement(ev); |
| float pos = getPos(ev); |
| float delta = pos - mInitialTouchPos; |
| if (Math.abs(delta) > mPagingTouchSlop) { |
| mCallback.onBeginDrag(mCurrView); |
| mDragging = true; |
| mInitialTouchPos = pos - getTranslation(mCurrView); |
| } |
| } |
| break; |
| case MotionEvent.ACTION_UP: |
| case MotionEvent.ACTION_CANCEL: |
| mDragging = false; |
| mCurrView = null; |
| break; |
| } |
| return mDragging; |
| } |
| |
| /** |
| * @param view The view to be dismissed |
| * @param velocity The desired pixels/second speed at which the view should move |
| */ |
| private void dismissChild(final View view, float velocity) { |
| final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view); |
| float newPos; |
| if (velocity < 0 |
| || (velocity == 0 && getTranslation(view) < 0) |
| // if we use the Menu to dismiss an item in landscape, animate up |
| || (velocity == 0 && getTranslation(view) == 0 && mSwipeDirection == Y)) { |
| newPos = -getSize(view); |
| } else { |
| newPos = getSize(view); |
| } |
| int duration = MAX_ESCAPE_ANIMATION_DURATION; |
| if (velocity != 0) { |
| duration = Math.min(duration, |
| (int) (Math.abs(newPos - getTranslation(view)) * |
| 1000f / Math.abs(velocity))); |
| } else { |
| duration = DEFAULT_ESCAPE_ANIMATION_DURATION; |
| } |
| |
| ValueAnimator anim = createTranslationAnimation(view, newPos); |
| anim.setInterpolator(sLinearInterpolator); |
| anim.setDuration(duration); |
| anim.addListener(new AnimatorListenerAdapter() { |
| @Override |
| public void onAnimationEnd(Animator animation) { |
| mCallback.onChildDismissed(view); |
| if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { |
| view.setAlpha(1.f); |
| } |
| } |
| }); |
| anim.addUpdateListener(new AnimatorUpdateListener() { |
| @Override |
| public void onAnimationUpdate(ValueAnimator animation) { |
| if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { |
| view.setAlpha(getAlphaForOffset(view)); |
| } |
| } |
| }); |
| anim.start(); |
| } |
| |
| private void snapChild(final View view, float velocity) { |
| final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view); |
| ValueAnimator anim = createTranslationAnimation(view, 0); |
| int duration = SNAP_ANIM_LEN; |
| anim.setDuration(duration); |
| anim.setInterpolator(RecentsConfiguration.getInstance().linearOutSlowInInterpolator); |
| anim.addUpdateListener(new AnimatorUpdateListener() { |
| @Override |
| public void onAnimationUpdate(ValueAnimator animation) { |
| if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { |
| view.setAlpha(getAlphaForOffset(view)); |
| } |
| mCallback.onSwipeChanged(mCurrView, view.getTranslationX()); |
| } |
| }); |
| anim.addListener(new AnimatorListenerAdapter() { |
| @Override |
| public void onAnimationEnd(Animator animation) { |
| if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { |
| view.setAlpha(1.0f); |
| } |
| mCallback.onSnapBackCompleted(view); |
| } |
| }); |
| anim.start(); |
| } |
| |
| public boolean onTouchEvent(MotionEvent ev) { |
| if (!mDragging) { |
| if (!onInterceptTouchEvent(ev)) { |
| return mCanCurrViewBeDimissed; |
| } |
| } |
| |
| mVelocityTracker.addMovement(ev); |
| final int action = ev.getAction(); |
| switch (action) { |
| case MotionEvent.ACTION_OUTSIDE: |
| case MotionEvent.ACTION_MOVE: |
| if (mCurrView != null) { |
| float delta = getPos(ev) - mInitialTouchPos; |
| setSwipeAmount(delta); |
| mCallback.onSwipeChanged(mCurrView, delta); |
| } |
| break; |
| case MotionEvent.ACTION_UP: |
| case MotionEvent.ACTION_CANCEL: |
| if (mCurrView != null) { |
| endSwipe(mVelocityTracker); |
| } |
| break; |
| } |
| return true; |
| } |
| |
| private void setSwipeAmount(float amount) { |
| // don't let items that can't be dismissed be dragged more than |
| // maxScrollDistance |
| if (CONSTRAIN_SWIPE |
| && (!isValidSwipeDirection(amount) || !mCallback.canChildBeDismissed(mCurrView))) { |
| float size = getSize(mCurrView); |
| float maxScrollDistance = 0.15f * size; |
| if (Math.abs(amount) >= size) { |
| amount = amount > 0 ? maxScrollDistance : -maxScrollDistance; |
| } else { |
| amount = maxScrollDistance * (float) Math.sin((amount/size)*(Math.PI/2)); |
| } |
| } |
| setTranslation(mCurrView, amount); |
| if (FADE_OUT_DURING_SWIPE && mCanCurrViewBeDimissed) { |
| float alpha = getAlphaForOffset(mCurrView); |
| mCurrView.setAlpha(alpha); |
| } |
| } |
| |
| private boolean isValidSwipeDirection(float amount) { |
| if (mSwipeDirection == X) { |
| if (mRtl) { |
| return (amount <= 0) ? mAllowSwipeTowardsEnd : mAllowSwipeTowardsStart; |
| } else { |
| return (amount <= 0) ? mAllowSwipeTowardsStart : mAllowSwipeTowardsEnd; |
| } |
| } |
| |
| // Vertical swipes are always valid. |
| return true; |
| } |
| |
| private void endSwipe(VelocityTracker velocityTracker) { |
| float maxVelocity = MAX_DISMISS_VELOCITY * mDensityScale; |
| velocityTracker.computeCurrentVelocity(1000 /* px/sec */, maxVelocity); |
| float velocity = getVelocity(velocityTracker); |
| float perpendicularVelocity = getPerpendicularVelocity(velocityTracker); |
| float escapeVelocity = SWIPE_ESCAPE_VELOCITY * mDensityScale; |
| float translation = getTranslation(mCurrView); |
| // Decide whether to dismiss the current view |
| boolean childSwipedFarEnough = DISMISS_IF_SWIPED_FAR_ENOUGH && |
| Math.abs(translation) > 0.6 * getSize(mCurrView); |
| boolean childSwipedFastEnough = (Math.abs(velocity) > escapeVelocity) && |
| (Math.abs(velocity) > Math.abs(perpendicularVelocity)) && |
| (velocity > 0) == (translation > 0); |
| |
| boolean dismissChild = mCallback.canChildBeDismissed(mCurrView) |
| && isValidSwipeDirection(translation) |
| && (childSwipedFastEnough || childSwipedFarEnough); |
| |
| if (dismissChild) { |
| // flingadingy |
| dismissChild(mCurrView, childSwipedFastEnough ? velocity : 0f); |
| } else { |
| // snappity |
| mCallback.onDragCancelled(mCurrView); |
| snapChild(mCurrView, velocity); |
| } |
| } |
| |
| public interface Callback { |
| View getChildAtPosition(MotionEvent ev); |
| |
| boolean canChildBeDismissed(View v); |
| |
| void onBeginDrag(View v); |
| |
| void onSwipeChanged(View v, float delta); |
| |
| void onChildDismissed(View v); |
| |
| void onSnapBackCompleted(View v); |
| |
| void onDragCancelled(View v); |
| } |
| } |