DropTarget.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.iwedia.gui.widgets;

import android.graphics.Rect;

/**
 * Interface defining an object that can receive a view at the end of a drag
 * operation.
 */
public interface DropTarget {
    /**
     * Handle an object being dropped on the DropTarget
     * 
     * @param source
     *        DragSource where the drag started
     * @param x
     *        X coordinate of the drop location
     * @param y
     *        Y coordinate of the drop location
     * @param xOffset
     *        Horizontal offset with the object being dragged where the original
     *        touch happened
     * @param yOffset
     *        Vertical offset with the object being dragged where the original
     *        touch happened
     * @param dragView
     *        The DragView that's being dragged around on screen.
     * @param dragInfo
     *        Data associated with the object being dragged
     */
    void onDrop(DragSource source, int x, int y, int xOffset, int yOffset,
            DragView dragView, Object dragInfo);

    void onDragEnter(DragSource source, int x, int y, int xOffset, int yOffset,
            DragView dragView, Object dragInfo);

    void onDragOver(DragSource source, int x, int y, int xOffset, int yOffset,
            DragView dragView, Object dragInfo);

    void onDragExit(DragSource source, int x, int y, int xOffset, int yOffset,
            DragView dragView, Object dragInfo);

    /**
     * Check if a drop action can occur at, or near, the requested location.
     * This may be called repeatedly during a drag, so any calls should return
     * quickly.
     * 
     * @param source
     *        DragSource where the drag started
     * @param x
     *        X coordinate of the drop location
     * @param y
     *        Y coordinate of the drop location
     * @param xOffset
     *        Horizontal offset with the object being dragged where the original
     *        touch happened
     * @param yOffset
     *        Vertical offset with the object being dragged where the original
     *        touch happened
     * @param dragView
     *        The DragView that's being dragged around on screen.
     * @param dragInfo
     *        Data associated with the object being dragged
     * @return True if the drop will be accepted, false otherwise.
     */
    boolean acceptDrop(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo);

    /**
     * Estimate the surface area where this object would land if dropped at the
     * given location.
     * 
     * @param source
     *        DragSource where the drag started
     * @param x
     *        X coordinate of the drop location
     * @param y
     *        Y coordinate of the drop location
     * @param xOffset
     *        Horizontal offset with the object being dragged where the original
     *        touch happened
     * @param yOffset
     *        Vertical offset with the object being dragged where the original
     *        touch happened
     * @param dragView
     *        The DragView that's being dragged around on screen.
     * @param dragInfo
     *        Data associated with the object being dragged
     * @param recycle
     *        {@link Rect} object to be possibly recycled.
     * @return Estimated area that would be occupied if object was dropped at
     *         the given location. Should return null if no estimate is found,
     *         or if this target doesn't provide estimations.
     */
    Rect estimateDropLocation(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo, Rect recycle);

    // These methods are implemented in Views
    void getHitRect(Rect outRect);

    void getLocationOnScreen(int[] loc);

    int getLeft();

    int getTop();
}