android DragLayer源码

Android_launcher的源码详细分析
http://www.cnblogs.com/playing/archive/2011/04/22/2024980.html
/* * 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 com.android.launcher;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Matrix;import android.graphics.Rect;import android.graphics.RectF;import android.graphics.Paint;import android.graphics.PorterDuffColorFilter;源码import android.graphics.PorterDuff;import android.os.Vibrator;import android.os.SystemClock;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.view.KeyEvent;import android.widget.FrameLayout;/** * A ViewGroup that coordinated dragging across its dscendants */public class DragLayer extends FrameLayout implements DragController {    private static final int SCROLL_DELAY = 600;    private static final int SCROLL_ZONE = 20;    private static final int VIBRATE_DURATION = 35;    private static final int ANIMATION_SCALE_UP_DURATION = 110;    private static final boolean PROFILE_DRAWING_DURING_DRAG = false;    // Number of pixels to add to the dragged item for scaling    private static final float DRAG_SCALE = 24.0f;    private boolean mDragging = false;    private boolean mShouldDrop;    private float mLastMotionX;    private float mLastMotionY;        /**     * The bitmap that is currently being dragged     */    private Bitmap mDragBitmap = null;    private View mOriginator;    private int mBitmapOffsetX;    private int mBitmapOffsetY;    /**     * X offset from where we touched on the cell to its upper-left corner     */    private float mTouchOffsetX;        /**     * Y offset from where we touched on the cell to its upper-left corner     */    private float mTouchOffsetY;        /**     * Utility rectangle     */    private Rect mDragRect = new Rect();        /**     * Where the drag originated     */    private DragSource mDragSource;        /**     * The data associated with the object being dragged     */    private Object mDragInfo;    private final Rect mRect = new Rect();        private final int[] mDropCoordinates = new int[2];    private final Vibrator mVibrator = new Vibrator();        private DragListener mListener;    private DragScroller mDragScroller;        private static final int SCROLL_OUTSIDE_ZONE = 0;    private static final int SCROLL_WAITING_IN_ZONE = 1;    private static final int SCROLL_LEFT = 0;    private static final int SCROLL_RIGHT = 1;        private int mScrollState = SCROLL_OUTSIDE_ZONE;    private ScrollRunnable mScrollRunnable = new ScrollRunnable();    private View mIgnoredDropTarget;    private RectF mDragRegion;    private boolean mEnteredRegion;    private DropTarget mLastDropTarget;    private final Paint mTrashPaint = new Paint();    private Paint mDragPaint;    private static final int ANIMATION_STATE_STARTING = 1;    private static final int ANIMATION_STATE_RUNNING = 2;    private static final int ANIMATION_STATE_DONE = 3;    private static final int ANIMATION_TYPE_SCALE = 1;    private float mAnimationFrom;    private float mAnimationTo;    private int mAnimationDuration;    private long mAnimationStartTime;    private int mAnimationType;    private int mAnimationState = ANIMATION_STATE_DONE;    /**     * Used to create a new DragLayer from XML.     *     * @param context The application's context.     * @param attrs The attribtues set containing the Workspace's customization values.     */    public DragLayer(Context context, AttributeSet attrs) {        super(context, attrs);        final int srcColor = context.getResources().getColor(R.color.delete_color_filter);        mTrashPaint.setColorFilter(new PorterDuffColorFilter(srcColor, PorterDuff.Mode.SRC_ATOP));    }    public void startDrag(View v, DragSource source, Object dragInfo, int dragAction) {        if (PROFILE_DRAWING_DURING_DRAG) {            android.os.Debug.startMethodTracing("Launcher");        }                if (mListener != null) {            mListener.onDragStart(v, source, dragInfo, dragAction);        }        Rect r = mDragRect;        r.set(v.getScrollX(), v.getScrollY(), 0, 0);        offsetDescendantRectToMyCoords(v, r);        mTouchOffsetX = mLastMotionX - r.left;        mTouchOffsetY = mLastMotionY - r.top;        v.clearFocus();        v.setPressed(false);        boolean willNotCache = v.willNotCacheDrawing();        v.setWillNotCacheDrawing(false);        v.buildDrawingCache();        Bitmap viewBitmap = v.getDrawingCache();        int width = viewBitmap.getWidth();        int height = viewBitmap.getHeight();        Matrix scale = new Matrix();        float scaleFactor = v.getWidth();        scaleFactor = (scaleFactor + DRAG_SCALE) /scaleFactor;        scale.setScale(scaleFactor, scaleFactor);        mAnimationTo = 1.0f;        mAnimationFrom = 1.0f / scaleFactor;        mAnimationDuration = ANIMATION_SCALE_UP_DURATION;        mAnimationState = ANIMATION_STATE_STARTING;        mAnimationType = ANIMATION_TYPE_SCALE;        mDragBitmap = Bitmap.createBitmap(viewBitmap, 0, 0, width, height, scale, true);        v.destroyDrawingCache();        v.setWillNotCacheDrawing(willNotCache);        final Bitmap dragBitmap = mDragBitmap;        mBitmapOffsetX = (dragBitmap.getWidth() - width) / 2;        mBitmapOffsetY = (dragBitmap.getHeight() - height) / 2;        if (dragAction == DRAG_ACTION_MOVE) {            v.setVisibility(GONE);        }        mDragPaint = null;        mDragging = true;        mShouldDrop = true;        mOriginator = v;        mDragSource = source;        mDragInfo = dragInfo;        mVibrator.vibrate(VIBRATE_DURATION);        mEnteredRegion = false;        invalidate();    }    @Override    public boolean dispatchKeyEvent(KeyEvent event) {        return mDragging || super.dispatchKeyEvent(event);    }    @Override    protected void dispatchDraw(Canvas canvas) {        super.dispatchDraw(canvas);        if (mDragging && mDragBitmap != null) {            if (mAnimationState == ANIMATION_STATE_STARTING) {                mAnimationStartTime = SystemClock.uptimeMillis();                mAnimationState = ANIMATION_STATE_RUNNING;            }            if (mAnimationState == ANIMATION_STATE_RUNNING) {                float normalized = (float) (SystemClock.uptimeMillis() - mAnimationStartTime) /                        mAnimationDuration;                if (normalized >= 1.0f) {                    mAnimationState = ANIMATION_STATE_DONE;                }                normalized = Math.min(normalized, 1.0f);                final float value = mAnimationFrom  + (mAnimationTo - mAnimationFrom) * normalized;                switch (mAnimationType) {                    case ANIMATION_TYPE_SCALE:                        final Bitmap dragBitmap = mDragBitmap;                        canvas.save();                        canvas.translate(mScrollX + mLastMotionX - mTouchOffsetX - mBitmapOffsetX,                                mScrollY + mLastMotionY - mTouchOffsetY - mBitmapOffsetY);                        canvas.translate((dragBitmap.getWidth() * (1.0f - value)) / 2,                                (dragBitmap.getHeight() * (1.0f - value)) / 2);                        canvas.scale(value, value);                        canvas.drawBitmap(dragBitmap, 0.0f, 0.0f, mDragPaint);                        canvas.restore();                        break;                }            } else {                canvas.drawBitmap(mDragBitmap,                        mScrollX + mLastMotionX - mTouchOffsetX - mBitmapOffsetX,                        mScrollY + mLastMotionY - mTouchOffsetY - mBitmapOffsetY, mDragPaint);            }        }    }    private void endDrag() {        if (mDragging) {            mDragging = false;            if (mDragBitmap != null) {                mDragBitmap.recycle();            }            if (mOriginator != null) {                mOriginator.setVisibility(VISIBLE);            }            if (mListener != null) {                mListener.onDragEnd();            }        }    }    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        final int action = ev.getAction();        final float x = ev.getX();        final float y = ev.getY();        switch (action) {            case MotionEvent.ACTION_MOVE:                break;            case MotionEvent.ACTION_DOWN:                // Remember location of down touch                mLastMotionX = x;                mLastMotionY = y;                mLastDropTarget = null;                break;            case MotionEvent.ACTION_CANCEL:            case MotionEvent.ACTION_UP:                if (mShouldDrop && drop(x, y)) {                    mShouldDrop = false;                }                endDrag();                break;        }        return mDragging;    }    @Override    public boolean onTouchEvent(MotionEvent ev) {        if (!mDragging) {            return false;        }        final int action = ev.getAction();        final float x = ev.getX();        final float y = ev.getY();        switch (action) {        case MotionEvent.ACTION_DOWN:            // Remember where the motion event started            mLastMotionX = x;            mLastMotionY = y;            if ((x < SCROLL_ZONE) || (x > getWidth() - SCROLL_ZONE)) {                mScrollState = SCROLL_WAITING_IN_ZONE;                postDelayed(mScrollRunnable, SCROLL_DELAY);            } else {                mScrollState = SCROLL_OUTSIDE_ZONE;            }            break;        case MotionEvent.ACTION_MOVE:            if (Launcher.sOpenGlEnabled) {                mLastMotionX = x;                mLastMotionY = y;                invalidate();            } else {                final int scrollX = mScrollX;                final int scrollY = mScrollY;                final float touchX = mTouchOffsetX;                final float touchY = mTouchOffsetY;                final int offsetX = mBitmapOffsetX;                final int offsetY = mBitmapOffsetY;                int left = (int) (scrollX + mLastMotionX - touchX - offsetX);                int top = (int) (scrollY + mLastMotionY - touchY - offsetY);                final Bitmap dragBitmap = mDragBitmap;                final int width = dragBitmap.getWidth();                final int height = dragBitmap.getHeight();                final Rect rect = mRect;                rect.set(left - 1, top - 1, left + width + 1, top + height + 1);                mLastMotionX = x;                mLastMotionY = y;                left = (int) (scrollX + x - touchX - offsetX);                top = (int) (scrollY + y - touchY - offsetY);                rect.union(left - 1, top - 1, left + width + 1, top + height + 1);                invalidate(rect);            }            final int[] coordinates = mDropCoordinates;            DropTarget dropTarget = findDropTarget((int) x, (int) y, coordinates);            if (dropTarget != null) {                if (mLastDropTarget == dropTarget) {                    dropTarget.onDragOver(mDragSource, coordinates[0], coordinates[1],                        (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo);                } else {                    if (mLastDropTarget != null) {                        mLastDropTarget.onDragExit(mDragSource, coordinates[0], coordinates[1],                            (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo);                    }                    dropTarget.onDragEnter(mDragSource, coordinates[0], coordinates[1],                        (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo);                }            } else {                if (mLastDropTarget != null) {                    mLastDropTarget.onDragExit(mDragSource, coordinates[0], coordinates[1],                        (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo);                }            }            mLastDropTarget = dropTarget;            boolean inDragRegion = false;            if (mDragRegion != null) {                final RectF region = mDragRegion;                final boolean inRegion = region.contains(ev.getRawX(), ev.getRawY());                if (!mEnteredRegion && inRegion) {                    mDragPaint = mTrashPaint;                    mEnteredRegion = true;                    inDragRegion = true;                } else if (mEnteredRegion && !inRegion) {                    mDragPaint = null;                    mEnteredRegion = false;                }            }            if (!inDragRegion && x < SCROLL_ZONE) {                if (mScrollState == SCROLL_OUTSIDE_ZONE) {                    mScrollState = SCROLL_WAITING_IN_ZONE;                    mScrollRunnable.setDirection(SCROLL_LEFT);                    postDelayed(mScrollRunnable, SCROLL_DELAY);                }            } else if (!inDragRegion && x > getWidth() - SCROLL_ZONE) {                if (mScrollState == SCROLL_OUTSIDE_ZONE) {                    mScrollState = SCROLL_WAITING_IN_ZONE;                    mScrollRunnable.setDirection(SCROLL_RIGHT);                    postDelayed(mScrollRunnable, SCROLL_DELAY);                }            } else {                if (mScrollState == SCROLL_WAITING_IN_ZONE) {                    mScrollState = SCROLL_OUTSIDE_ZONE;                    mScrollRunnable.setDirection(SCROLL_RIGHT);                    removeCallbacks(mScrollRunnable);                }            }            break;        case MotionEvent.ACTION_UP:            removeCallbacks(mScrollRunnable);            if (mShouldDrop) {                drop(x, y);                mShouldDrop = false;            }            endDrag();            break;        case MotionEvent.ACTION_CANCEL:            endDrag();        }        return true;    }    private boolean drop(float x, float y) {        invalidate();        final int[] coordinates = mDropCoordinates;        DropTarget dropTarget = findDropTarget((int) x, (int) y, coordinates);        if (dropTarget != null) {            dropTarget.onDragExit(mDragSource, coordinates[0], coordinates[1],                    (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo);            if (dropTarget.acceptDrop(mDragSource, coordinates[0], coordinates[1],                    (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo)) {                dropTarget.onDrop(mDragSource, coordinates[0], coordinates[1],                        (int) mTouchOffsetX, (int) mTouchOffsetY, mDragInfo);                mDragSource.onDropCompleted((View) dropTarget, true);                return true;            } else {                mDragSource.onDropCompleted((View) dropTarget, false);                return true;            }        }        return false;    }    DropTarget findDropTarget(int x, int y, int[] dropCoordinates) {        return findDropTarget(this, x, y, dropCoordinates);    }    private DropTarget findDropTarget(ViewGroup container, int x, int y, int[] dropCoordinates) {        final Rect r = mDragRect;        final int count = container.getChildCount();        final int scrolledX = x + container.getScrollX();        final int scrolledY = y + container.getScrollY();        final View ignoredDropTarget = mIgnoredDropTarget;        for (int i = count - 1; i >= 0; i--) {            final View child = container.getChildAt(i);            if (child.getVisibility() == VISIBLE && child != ignoredDropTarget) {                child.getHitRect(r);                if (r.contains(scrolledX, scrolledY)) {                    DropTarget target = null;                    if (child instanceof ViewGroup) {                        x = scrolledX - child.getLeft();                        y = scrolledY - child.getTop();                        target = findDropTarget((ViewGroup) child, x, y, dropCoordinates);                    }                    if (target == null) {                        if (child instanceof DropTarget) {                            dropCoordinates[0] = x;                            dropCoordinates[1] = y;                            return (DropTarget) child;                        }                    } else {                        return target;                    }                }            }        }        return null;    }    public void setDragScoller(DragScroller scroller) {        mDragScroller = scroller;    }    public void setDragListener(DragListener l) {        mListener = l;    }    public void removeDragListener(DragListener l) {        mListener = null;       }    /**     * Specifies the view that must be ignored when looking for a drop target.     *     * @param view The view that will not be taken into account while looking     *        for a drop target.     */    void setIgnoredDropTarget(View view) {        mIgnoredDropTarget = view;    }    /**     * Specifies the delete region.     *     * @param region The rectangle in screen coordinates of the delete region.     */    void setDeleteRegion(RectF region) {        mDragRegion = region;    }    private class ScrollRunnable implements Runnable {        private int mDirection;        ScrollRunnable() {        }        public void run() {            if (mDragScroller != null) {                if (mDirection == SCROLL_LEFT) {                    mDragScroller.scrollLeft();                } else {                    mDragScroller.scrollRight();                }                mScrollState = SCROLL_OUTSIDE_ZONE;            }        }        void setDirection(int direction) {            mDirection = direction;        }    }    }
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