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/*
* 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.launcher3;
import android.graphics.Rect;
import com.android.launcher3.accessibility.DragViewStateAnnouncer;
import com.android.launcher3.dragndrop.DragOptions;
import com.android.launcher3.dragndrop.DragView;
/**
* Interface defining an object that can receive a drag.
*
*/
public interface 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, after item is dropped. */
public ItemInfo dragInfo = null;
/** The data associated with the object being dragged */
public ItemInfo originalDragInfo = null;
/** Where the drag originated */
public DragSource dragSource = null;
/** The object is part of an accessible drag operation */
public boolean accessibleDrag;
/** 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 DragViewStateAnnouncer stateAnnouncer;
public DragObject() {
}
/**
* This is used to compute the visual center of the dragView. This point is then
* used to visualize drop locations and determine where to drop an item. The idea is that
* the visual center represents the user's interpretation of where the item is, and hence
* is the appropriate point to use when determining drop location.
*/
public final float[] getVisualCenter(float[] recycle) {
final float res[] = (recycle == null) ? new float[2] : recycle;
Rect dragRegion = dragView.getDragRegion();
// These represent the visual top and left of drag view if a dragRect was provided.
// If a dragRect was not provided, then they correspond to the actual view left and
// top, as the dragRect is in that case taken to be the entire dragView.
int left = x - xOffset - dragRegion.left;
int top = y - yOffset - dragRegion.top;
// In order to find the visual center, we shift by half the dragRect
res[0] = left + dragRegion.width() / 2;
res[1] = top + dragRegion.height() / 2;
return res;
}
}
/**
* 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.
*
* This will be called only if this target previously returned true for {@link #acceptDrop}. It
* is the responsibility of this target to exit out of the spring loaded mode (either
* immediately or after any pending animations).
*
* If the drop was cancelled for some reason, onDrop will never get called, the UI will
* automatically exit out of this mode.
*/
void onDrop(DragObject dragObject, DragOptions options);
void onDragEnter(DragObject dragObject);
void onDragOver(DragObject dragObject);
void onDragExit(DragObject dragObject);
/**
* Check if a drop action can occur at, or near, the requested location.
* This will be called just before onDrop.
* @return True if the drop will be accepted, false otherwise.
*/
boolean acceptDrop(DragObject dragObject);
void prepareAccessibilityDrop();
// These methods are implemented in Views
void getHitRectRelativeToDragLayer(Rect outRect);
}
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