| /* |
| * Copyright (C) 2006 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 android.text.method; |
| |
| import android.util.Log; |
| import android.view.KeyEvent; |
| import android.view.MotionEvent; |
| import android.text.*; |
| import android.widget.TextView; |
| import android.view.View; |
| |
| public class |
| ScrollingMovementMethod |
| implements MovementMethod |
| { |
| /** |
| * Scrolls the text to the left if possible. |
| */ |
| protected boolean left(TextView widget, Spannable buffer) { |
| Layout layout = widget.getLayout(); |
| |
| int scrolly = widget.getScrollY(); |
| int scr = widget.getScrollX(); |
| int em = Math.round(layout.getPaint().getFontSpacing()); |
| |
| int padding = widget.getTotalPaddingTop() + |
| widget.getTotalPaddingBottom(); |
| int top = layout.getLineForVertical(scrolly); |
| int bottom = layout.getLineForVertical(scrolly + widget.getHeight() - |
| padding); |
| int left = Integer.MAX_VALUE; |
| |
| for (int i = top; i <= bottom; i++) { |
| left = (int) Math.min(left, layout.getLineLeft(i)); |
| } |
| |
| if (scr > left) { |
| int s = Math.max(scr - em, left); |
| widget.scrollTo(s, widget.getScrollY()); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Scrolls the text to the right if possible. |
| */ |
| protected boolean right(TextView widget, Spannable buffer) { |
| Layout layout = widget.getLayout(); |
| |
| int scrolly = widget.getScrollY(); |
| int scr = widget.getScrollX(); |
| int em = Math.round(layout.getPaint().getFontSpacing()); |
| |
| int padding = widget.getTotalPaddingTop() + |
| widget.getTotalPaddingBottom(); |
| int top = layout.getLineForVertical(scrolly); |
| int bottom = layout.getLineForVertical(scrolly + widget.getHeight() - |
| padding); |
| int right = 0; |
| |
| for (int i = top; i <= bottom; i++) { |
| right = (int) Math.max(right, layout.getLineRight(i)); |
| } |
| |
| padding = widget.getTotalPaddingLeft() + widget.getTotalPaddingRight(); |
| if (scr < right - (widget.getWidth() - padding)) { |
| int s = Math.min(scr + em, right - (widget.getWidth() - padding)); |
| widget.scrollTo(s, widget.getScrollY()); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Scrolls the text up if possible. |
| */ |
| protected boolean up(TextView widget, Spannable buffer) { |
| Layout layout = widget.getLayout(); |
| |
| int areatop = widget.getScrollY(); |
| int line = layout.getLineForVertical(areatop); |
| int linetop = layout.getLineTop(line); |
| |
| // If the top line is partially visible, bring it all the way |
| // into view; otherwise, bring the previous line into view. |
| if (areatop == linetop) |
| line--; |
| |
| if (line >= 0) { |
| Touch.scrollTo(widget, layout, |
| widget.getScrollX(), layout.getLineTop(line)); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Scrolls the text down if possible. |
| */ |
| protected boolean down(TextView widget, Spannable buffer) { |
| Layout layout = widget.getLayout(); |
| |
| int padding = widget.getTotalPaddingTop() + |
| widget.getTotalPaddingBottom(); |
| |
| int areabot = widget.getScrollY() + widget.getHeight() - padding; |
| int line = layout.getLineForVertical(areabot); |
| |
| if (layout.getLineTop(line+1) < areabot + 1) { |
| // Less than a pixel of this line is out of view, |
| // so we must have tried to make it entirely in view |
| // and now want the next line to be in view instead. |
| |
| line++; |
| } |
| |
| if (line <= layout.getLineCount() - 1) { |
| widget.scrollTo(widget.getScrollX(), layout.getLineTop(line+1) - |
| (widget.getHeight() - padding)); |
| Touch.scrollTo(widget, layout, |
| widget.getScrollX(), widget.getScrollY()); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| public boolean onKeyDown(TextView widget, Spannable buffer, int keyCode, KeyEvent event) { |
| boolean handled = false; |
| |
| switch (keyCode) { |
| case KeyEvent.KEYCODE_DPAD_LEFT: |
| handled |= left(widget, buffer); |
| break; |
| |
| case KeyEvent.KEYCODE_DPAD_RIGHT: |
| handled |= right(widget, buffer); |
| break; |
| |
| case KeyEvent.KEYCODE_DPAD_UP: |
| handled |= up(widget, buffer); |
| break; |
| |
| case KeyEvent.KEYCODE_DPAD_DOWN: |
| handled |= down(widget, buffer); |
| break; |
| } |
| |
| return handled; |
| } |
| |
| public boolean onKeyUp(TextView widget, Spannable buffer, int keyCode, KeyEvent event) { |
| return false; |
| } |
| |
| public boolean onTouchEvent(TextView widget, Spannable buffer, |
| MotionEvent event) { |
| return Touch.onTouchEvent(widget, buffer, event); |
| } |
| |
| public boolean onTrackballEvent(TextView widget, Spannable buffer, |
| MotionEvent event) { |
| boolean handled = false; |
| int x = (int) event.getX(); |
| int y = (int) event.getY(); |
| |
| for (; y < 0; y++) { |
| handled |= up(widget, buffer); |
| } |
| for (; y > 0; y--) { |
| handled |= down(widget, buffer); |
| } |
| |
| for (; x < 0; x++) { |
| handled |= left(widget, buffer); |
| } |
| for (; x > 0; x--) { |
| handled |= right(widget, buffer); |
| } |
| |
| return handled; |
| } |
| |
| public void initialize(TextView widget, Spannable text) { } |
| |
| public boolean canSelectArbitrarily() { |
| return false; |
| } |
| |
| public void onTakeFocus(TextView widget, Spannable text, int dir) { |
| Layout layout = widget.getLayout(); |
| |
| if (layout != null && (dir & View.FOCUS_FORWARD) != 0) { |
| widget.scrollTo(widget.getScrollX(), |
| layout.getLineTop(0)); |
| } |
| if (layout != null && (dir & View.FOCUS_BACKWARD) != 0) { |
| int padding = widget.getTotalPaddingTop() + |
| widget.getTotalPaddingBottom(); |
| int line = layout.getLineCount() - 1; |
| |
| widget.scrollTo(widget.getScrollX(), |
| layout.getLineTop(line+1) - |
| (widget.getHeight() - padding)); |
| } |
| } |
| |
| public static MovementMethod getInstance() { |
| if (sInstance == null) |
| sInstance = new ScrollingMovementMethod(); |
| |
| return sInstance; |
| } |
| |
| private static ScrollingMovementMethod sInstance; |
| } |