src/com/android/launcher2/DragLayer.java

/*
 * 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.launcher2;

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.ImageView;

import com.android.launcher.R;

/**
 * A ViewGroup that coordinates dragging across its descendants
 */
public class DragLayer extends FrameLayout {
    private DragController mDragController;
    private int[] mTmpXY = new int[2];

    // Variables relating to resizing widgets
    private final ArrayList<AppWidgetResizeFrame> mResizeFrames =
            new ArrayList<AppWidgetResizeFrame>();
    private AppWidgetResizeFrame mCurrentResizeFrame;
    private int mXDown, mYDown;

    /**
     * Used to create a new DragLayer from XML.
     *
     * @param context The application's context.
     * @param attrs The attributes set containing the Workspace's customization values.
     */
    public DragLayer(Context context, AttributeSet attrs) {
        super(context, attrs);

        // Disable multitouch across the workspace/all apps/customize tray
        setMotionEventSplittingEnabled(false);
    }

    public void setDragController(DragController controller) {
        mDragController = controller;
    }
    
    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        return mDragController.dispatchKeyEvent(event) || super.dispatchKeyEvent(event);
    }

    private boolean handleTouchDown(MotionEvent ev) {
        Rect hitRect = new Rect();
        int x = (int) ev.getX();
        int y = (int) ev.getY();

        for (AppWidgetResizeFrame child: mResizeFrames) {
            child.getHitRect(hitRect);
            if (hitRect.contains(x, y)) {
                if (child.beginResizeIfPointInRegion(x - child.getLeft(), y - child.getTop())) {
                    mCurrentResizeFrame = child;
                    mXDown = x;
                    mYDown = y;
                    requestDisallowInterceptTouchEvent(true);
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            if (handleTouchDown(ev)) {
                return true;
            }
        }
        clearAllResizeFrames();
        return mDragController.onInterceptTouchEvent(ev);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        boolean handled = false;
        int action = ev.getAction();

        int x = (int) ev.getX();
        int y = (int) ev.getY();

        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            if (ev.getAction() == MotionEvent.ACTION_DOWN) {
                if (handleTouchDown(ev)) {
                    return true;
                }
            }
        }

        if (mCurrentResizeFrame != null) {
            handled = true;
            switch (action) {
                case MotionEvent.ACTION_MOVE:
                    mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
                    break;
                case MotionEvent.ACTION_CANCEL:
                case MotionEvent.ACTION_UP:
                    mCurrentResizeFrame.commitResizeForDelta(x - mXDown, y - mYDown);
                    mCurrentResizeFrame = null;
            }
        }
        if (handled) return true;
        return mDragController.onTouchEvent(ev);
    }

    @Override
    public boolean dispatchUnhandledMove(View focused, int direction) {
        return mDragController.dispatchUnhandledMove(focused, direction);
    }

    public View createDragView(Bitmap b, int xPos, int yPos) {
        ImageView imageView = new ImageView(mContext);
        imageView.setImageBitmap(b);
        imageView.setX(xPos);
        imageView.setY(yPos);
        addView(imageView, b.getWidth(), b.getHeight());

        return imageView;
    }

    public View createDragView(View v) {
        v.getLocationOnScreen(mTmpXY);
        return createDragView(mDragController.getViewBitmap(v), mTmpXY[0], mTmpXY[1]);
    }

    public static class LayoutParams extends FrameLayout.LayoutParams {
        public int x, y;
        public boolean customPosition = false;

        /**
         * {@inheritDoc}
         */
        public LayoutParams(int width, int height) {
            super(width, height);
        }

        public void setWidth(int width) {
            this.width = width;
        }

        public int getWidth() {
            return width;
        }

        public void setHeight(int height) {
            this.height = height;
        }

        public int getHeight() {
            return height;
        }

        public void setX(int x) {
            this.x = x;
        }

        public int getX() {
            return x;
        }

        public void setY(int y) {
            this.y = y;
        }

        public int getY() {
            return y;
        }
    }

    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);
        int count = getChildCount();
        for (int i = 0; i < count; i++) {
            View child = getChildAt(i);
            final FrameLayout.LayoutParams flp = (FrameLayout.LayoutParams) child.getLayoutParams();
            if (flp instanceof LayoutParams) {
                final LayoutParams lp = (LayoutParams) flp;
                if (lp.customPosition) {
                    child.layout(lp.x, lp.y, lp.x + lp.width, lp.y + lp.height);
                }
            }
        }
    }

    public void clearAllResizeFrames() {
        if (mResizeFrames.size() > 0) {
            for (AppWidgetResizeFrame frame: mResizeFrames) {
                removeView(frame);
            }
            mResizeFrames.clear();
        }
    }

    public boolean hasResizeFrames() {
        return mResizeFrames.size() > 0;
    }

    public boolean isWidgetBeingResized() {
        return mCurrentResizeFrame != null;
    }

    public void addResizeFrame(ItemInfo itemInfo, LauncherAppWidgetHostView widget,
            CellLayout cellLayout) {
        AppWidgetResizeFrame resizeFrame = new AppWidgetResizeFrame(getContext(),
                itemInfo, widget, cellLayout, this);

        LayoutParams lp = new LayoutParams(-1, -1);
        lp.customPosition = true;

        addView(resizeFrame, lp);
        mResizeFrames.add(resizeFrame);

        resizeFrame.snapToWidget(false);
    }
}