| /* |
| * Copyright (C) 2008 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.text.Layout; |
| import android.text.Layout.Alignment; |
| import android.text.NoCopySpan; |
| import android.text.Spannable; |
| import android.view.KeyEvent; |
| import android.view.MotionEvent; |
| import android.view.ViewConfiguration; |
| import android.widget.TextView; |
| |
| public class Touch { |
| private Touch() { } |
| |
| /** |
| * Scrolls the specified widget to the specified coordinates, except |
| * constrains the X scrolling position to the horizontal regions of |
| * the text that will be visible after scrolling to the specified |
| * Y position. |
| */ |
| public static void scrollTo(TextView widget, Layout layout, int x, int y) { |
| final int horizontalPadding = widget.getTotalPaddingLeft() + widget.getTotalPaddingRight(); |
| final int availableWidth = widget.getWidth() - horizontalPadding; |
| |
| final int top = layout.getLineForVertical(y); |
| Alignment a = layout.getParagraphAlignment(top); |
| boolean ltr = layout.getParagraphDirection(top) > 0; |
| |
| int left, right; |
| if (widget.getHorizontallyScrolling()) { |
| final int verticalPadding = widget.getTotalPaddingTop() + widget.getTotalPaddingBottom(); |
| final int bottom = layout.getLineForVertical(y + widget.getHeight() - verticalPadding); |
| |
| left = Integer.MAX_VALUE; |
| right = 0; |
| |
| for (int i = top; i <= bottom; i++) { |
| left = (int) Math.min(left, layout.getLineLeft(i)); |
| right = (int) Math.max(right, layout.getLineRight(i)); |
| } |
| } else { |
| left = 0; |
| right = availableWidth; |
| } |
| |
| final int actualWidth = right - left; |
| |
| if (actualWidth < availableWidth) { |
| if (a == Alignment.ALIGN_CENTER) { |
| x = left - ((availableWidth - actualWidth) / 2); |
| } else if ((ltr && (a == Alignment.ALIGN_OPPOSITE)) || |
| (!ltr && (a == Alignment.ALIGN_NORMAL)) || |
| (a == Alignment.ALIGN_RIGHT)) { |
| // align_opposite does NOT mean align_right, we need the paragraph |
| // direction to resolve it to left or right |
| x = left - (availableWidth - actualWidth); |
| } else { |
| x = left; |
| } |
| } else { |
| x = Math.min(x, right - availableWidth); |
| x = Math.max(x, left); |
| } |
| |
| widget.scrollTo(x, y); |
| } |
| |
| /** |
| * Handles touch events for dragging. You may want to do other actions |
| * like moving the cursor on touch as well. |
| */ |
| public static boolean onTouchEvent(TextView widget, Spannable buffer, |
| MotionEvent event) { |
| DragState[] ds; |
| |
| switch (event.getActionMasked()) { |
| case MotionEvent.ACTION_DOWN: |
| ds = buffer.getSpans(0, buffer.length(), DragState.class); |
| |
| for (int i = 0; i < ds.length; i++) { |
| buffer.removeSpan(ds[i]); |
| } |
| |
| buffer.setSpan(new DragState(event.getX(), event.getY(), |
| widget.getScrollX(), widget.getScrollY()), |
| 0, 0, Spannable.SPAN_MARK_MARK); |
| return true; |
| |
| case MotionEvent.ACTION_UP: |
| ds = buffer.getSpans(0, buffer.length(), DragState.class); |
| |
| for (int i = 0; i < ds.length; i++) { |
| buffer.removeSpan(ds[i]); |
| } |
| |
| if (ds.length > 0 && ds[0].mUsed) { |
| return true; |
| } else { |
| return false; |
| } |
| |
| case MotionEvent.ACTION_MOVE: |
| ds = buffer.getSpans(0, buffer.length(), DragState.class); |
| |
| if (ds.length > 0) { |
| if (ds[0].mFarEnough == false) { |
| int slop = ViewConfiguration.get(widget.getContext()).getScaledTouchSlop(); |
| |
| if (Math.abs(event.getX() - ds[0].mX) >= slop || |
| Math.abs(event.getY() - ds[0].mY) >= slop) { |
| ds[0].mFarEnough = true; |
| } |
| } |
| |
| if (ds[0].mFarEnough) { |
| ds[0].mUsed = true; |
| boolean cap = (event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0 |
| || MetaKeyKeyListener.getMetaState(buffer, |
| MetaKeyKeyListener.META_SHIFT_ON) == 1 |
| || MetaKeyKeyListener.getMetaState(buffer, |
| MetaKeyKeyListener.META_SELECTING) != 0; |
| |
| float dx; |
| float dy; |
| if (cap) { |
| // if we're selecting, we want the scroll to go in |
| // the direction of the drag |
| dx = event.getX() - ds[0].mX; |
| dy = event.getY() - ds[0].mY; |
| } else { |
| dx = ds[0].mX - event.getX(); |
| dy = ds[0].mY - event.getY(); |
| } |
| ds[0].mX = event.getX(); |
| ds[0].mY = event.getY(); |
| |
| int nx = widget.getScrollX() + (int) dx; |
| int ny = widget.getScrollY() + (int) dy; |
| |
| int padding = widget.getTotalPaddingTop() + widget.getTotalPaddingBottom(); |
| Layout layout = widget.getLayout(); |
| |
| ny = Math.min(ny, layout.getHeight() - (widget.getHeight() - padding)); |
| ny = Math.max(ny, 0); |
| |
| int oldX = widget.getScrollX(); |
| int oldY = widget.getScrollY(); |
| |
| scrollTo(widget, layout, nx, ny); |
| |
| // If we actually scrolled, then cancel the up action. |
| if (oldX != widget.getScrollX() || oldY != widget.getScrollY()) { |
| widget.cancelLongPress(); |
| } |
| |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * @param widget The text view. |
| * @param buffer The text buffer. |
| */ |
| public static int getInitialScrollX(TextView widget, Spannable buffer) { |
| DragState[] ds = buffer.getSpans(0, buffer.length(), DragState.class); |
| return ds.length > 0 ? ds[0].mScrollX : -1; |
| } |
| |
| /** |
| * @param widget The text view. |
| * @param buffer The text buffer. |
| */ |
| public static int getInitialScrollY(TextView widget, Spannable buffer) { |
| DragState[] ds = buffer.getSpans(0, buffer.length(), DragState.class); |
| return ds.length > 0 ? ds[0].mScrollY : -1; |
| } |
| |
| private static class DragState implements NoCopySpan { |
| public float mX; |
| public float mY; |
| public int mScrollX; |
| public int mScrollY; |
| public boolean mFarEnough; |
| public boolean mUsed; |
| |
| public DragState(float x, float y, int scrollX, int scrollY) { |
| mX = x; |
| mY = y; |
| mScrollX = scrollX; |
| mScrollY = scrollY; |
| } |
| } |
| } |