/*
* 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 android.content.Context;
import android.graphics.PointF;
import android.graphics.Rect;
import android.util.Log;
/**
* Interface defining an object that can receive a drag.
*
*/
public interface DropTarget {
public static final String TAG = "DropTarget";
class DragObject {
public int x = -1;
public int y = -1;
/** X offset from the upper-left corner of the cell to where we touched. */
public int xOffset = -1;
/** Y offset from the upper-left corner of the cell to where we touched. */
public int yOffset = -1;
/** This indicates whether a drag is in final stages, either drop or cancel. It
* differentiates onDragExit, since this is called when the drag is ending, above
* the current drag target, or when the drag moves off the current drag object.
*/
public boolean dragComplete = false;
/** The view that moves around while you drag. */
public DragView dragView = null;
/** The data associated with the object being dragged */
public Object dragInfo = null;
/** Where the drag originated */
public DragSource dragSource = null;
/** Post drag animation runnable */
public Runnable postAnimationRunnable = null;
/** Indicates that the drag operation was cancelled */
public boolean cancelled = false;
/** Defers removing the DragView from the DragLayer until after the drop animation. */
public boolean deferDragViewCleanupPostAnimation = true;
public DragObject() {
}
}
public static class DragEnforcer implements DragController.DragListener {
int dragParity = 0;
public DragEnforcer(Context context) {
Launcher launcher = (Launcher) context;
launcher.getDragController().addDragListener(this);
}
void onDragEnter() {
dragParity++;
if (dragParity != 1) {
Log.e(TAG, "onDragEnter: Drag contract violated: " + dragParity);
}
}
void onDragExit() {
dragParity--;
if (dragParity != 0) {
Log.e(TAG, "onDragExit: Drag contract violated: " + dragParity);
}
}
@Override
public void onDragStart(DragSource source, Object info, int dragAction) {
if (dragParity != 0) {
Log.e(TAG, "onDragEnter: Drag contract violated: " + dragParity);
}
}
@Override
public void onDragEnd() {
if (dragParity != 0) {
Log.e(TAG, "onDragExit: Drag contract violated: " + dragParity);
}
}
}
/**
* Used to temporarily disable certain drop targets
*
* @return boolean specifying whether this drop target is currently enabled
*/
boolean isDropEnabled();
/**
* 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(DragObject dragObject);
void onDragEnter(DragObject dragObject);
void onDragOver(DragObject dragObject);
void onDragExit(DragObject dragObject);
/**
* Handle an object being dropped as a result of flinging to delete and will be called in place
* of onDrop(). (This is only called on objects that are set as the DragController's
* fling-to-delete target.
*/
void onFlingToDelete(DragObject dragObject, int x, int y, PointF vec);
/**
* Allows a DropTarget to delegate drag and drop events to another object.
*
* Most subclasses will should just return null from this method.
*
* @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 The DropTarget to delegate to, or null to not delegate to another object.
*/
DropTarget getDropTargetDelegate(DragObject dragObject);
/**
* Check if a drop action can occur at, or near, the requested location.
* This will be called just before onDrop.
*
* @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(DragObject dragObject);
// These methods are implemented in Views
void getHitRect(Rect outRect);
void getLocationInDragLayer(int[] loc);
int getLeft();
int getTop();
}