DragLayer.java

/*
 * This is a modified version of a class from the Android Open Source Project. 
 * The original copyright and license information follows.
 * 
 * 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.blahti.drag;

import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.KeyEvent;
import android.view.View;

/**
 * A ViewGroup that coordinates dragging across its descendants.
 *
 * <p> This class used DragLayer in the Android Launcher activity as a model.
 * It is a bit different in several respects:
 * (1) It extends MyAbsoluteLayout rather than FrameLayout; (2) it implements DragSource and DropTarget methods
 * that were done in a separate Workspace class in the Launcher.
 */
public class DragLayer extends MyAbsoluteLayout implements DragSource, DropTarget {
    private DragController mDragController;

    public DragLayer (Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        return mDragController.dispatchKeyEvent(event) || super.dispatchKeyEvent(event);
    }
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return mDragController.onInterceptTouchEvent(ev);
    }
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return mDragController.onTouchEvent(ev);
    }
    @Override
    public boolean dispatchUnhandledMove(View focused, int direction) {
        return mDragController.dispatchUnhandledMove(focused, direction);
    }

    // Interfaces of DragSource
    @Override
    public boolean allowDrag() {
        return true;
    }
    @Override
    public void setDragController(DragController controller) {
        mDragController = controller;
    }
    @Override
    public void onDropCompleted(View target, boolean success) {
    }

    // Interfaces of DropTarget
    @Override
    public void onDrop(DragSource source, int x, int y, int xOffset, int yOffset, DragView dragView, Object dragInfo) {
        final View v = (View)dragInfo;
        final int w = v.getWidth();
        final int h = v.getHeight();
        final int left = x - xOffset;
        final int top = y - yOffset;
        final DragLayer.LayoutParams lp = new DragLayer.LayoutParams (w, h, left, top);
        updateViewLayout(v, lp);
    }
    @Override
    public void onDragEnter(DragSource source, int x, int y, int xOffset, int yOffset, DragView dragView, Object dragInfo) {
    }
    @Override
    public void onDragOver(DragSource source, int x, int y, int xOffset, int yOffset, DragView dragView, Object dragInfo) {
    }
    @Override
    public void onDragExit(DragSource source, int x, int y, int xOffset, int yOffset, DragView dragView, Object dragInfo) {
    }
    @Override
    public boolean acceptDrop(DragSource source, int x, int y, int xOffset, int yOffset, DragView dragView, Object dragInfo) {
        return true;
    }
    @Override
    public Rect estimateDropLocation(DragSource source, int x, int y, int xOffset, int yOffset, DragView dragView, Object dragInfo, Rect recycle) {
        return null;
    }
}