/*
* 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.Bitmap;
import android.graphics.Rect;
import android.os.IBinder;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.View;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.WindowManager;
import android.view.inputmethod.InputMethodManager;
import java.util.ArrayList;
/**
* This class is used to initiate a drag within a view or across multiple views.
* When a drag starts it creates a special view (a DragView) that moves around the screen
* until the user ends the drag. As feedback to the user, this object causes the device to
* vibrate as the drag begins.
*
*/
public class DragController {
public enum DragBehavior {
MOVE, // indicates the drag is move
COPY // indicates the drag is copy
}
public static final String TAG = "DragController";
private Context mContext;
private Rect mRectTemp = new Rect();
private final int[] mCoordinatesTemp = new int[2];
private boolean mDragging;
private float mMotionDownX;
private float mMotionDownY;
private DisplayMetrics mDisplayMetrics = new DisplayMetrics();
/** Original view that is being dragged. */
private View mOriginator;
/** X offset from the upper-left corner of the cell to where we touched. */
private float mTouchOffsetX;
/** Y offset from the upper-left corner of the cell to where we touched. */
private float mTouchOffsetY;
/** Where the drag originated */
private DragSource mDragSource;
/** The data associated with the object being dragged */
private Object mDragInfo;
/** The view that moves around while you drag. */
private DragView mDragView;
/** Who can receive drop events */
private ArrayList<DropTarget> mDropTargets = new ArrayList<DropTarget>();
private DragListener mListener;
/** The window token used as the parent for the DragView. */
private IBinder mWindowToken;
private View mMoveTarget;
private DropTarget mLastDropTarget;
private InputMethodManager mInputMethodManager;
/**
* Used to create a new DragLayer from XML.
*
* @param context The application's context.
*/
public DragController(Context context) {
mContext = context;
}
/**
* Starts a drag.
* It creates a bitmap of the view being dragged. That bitmap is what you see moving.
* The actual view can be repositioned if that is what the onDrop handle chooses to do.
*
* @param v The view that is being dragged
* @param source An object representing where the drag originated
* @param dragInfo The data associated with the object that is being dragged
* @param dragAction The drag behavior: move or copy
*/
public void startDrag(View v, DragSource source, Object dragInfo, DragBehavior dragBehavior) {
if (source.allowDrag()) {
mOriginator = v;
final Bitmap b = getViewBitmap(v);
if (b != null) {
final int[] loc = mCoordinatesTemp;
v.getLocationOnScreen(loc);
final int screenX = loc[0];
final int screenY = loc[1];
startDrag(b, screenX, screenY, 0, 0, b.getWidth(), b.getHeight(), source, dragInfo, dragBehavior);
b.recycle();
if (dragBehavior == DragBehavior.MOVE) {
v.setVisibility(View.GONE);
}
}
}
}
/**
* Starts a drag.
*
* @param b The bitmap to display as the drag image. It will be re-scaled to the
* enlarged size.
* @param screenX The x position on screen of the left-top of the bitmap.
* @param screenY The y position on screen of the left-top of the bitmap.
* @param textureLeft The left edge of the region inside b to use.
* @param textureTop The top edge of the region inside b to use.
* @param textureWidth The width of the region inside b to use.
* @param textureHeight The height of the region inside b to use.
* @param source An object representing where the drag originated
* @param dragInfo The data associated with the object that is being dragged
* @param dragBehavior The drag action: move or copy
*/
private void startDrag(Bitmap b, int screenX, int screenY, int textureLeft, int textureTop, int textureWidth, int textureHeight, DragSource source, Object dragInfo, DragBehavior dragBehavior) {
if (mInputMethodManager == null) {
mInputMethodManager = (InputMethodManager) mContext.getSystemService(Context.INPUT_METHOD_SERVICE);
}
mInputMethodManager.hideSoftInputFromWindow(mWindowToken, 0);
if (mListener != null) {
mListener.onDragStart(source, dragInfo, dragBehavior);
}
final int registrationX = ((int)mMotionDownX) - screenX;
final int registrationY = ((int)mMotionDownY) - screenY;
mTouchOffsetX = mMotionDownX - screenX;
mTouchOffsetY = mMotionDownY - screenY;
mDragging = true;
mDragSource = source;
mDragInfo = dragInfo;
mDragView = new DragView(mContext, b, registrationX, registrationY, textureLeft, textureTop, textureWidth, textureHeight);
mDragView.show(mWindowToken, (int)mMotionDownX, (int)mMotionDownY);
}
/**
* Draw the view into a bitmap.
*/
private Bitmap getViewBitmap(View v) {
v.clearFocus();
v.setPressed(false);
boolean willNotCache = v.willNotCacheDrawing();
v.setWillNotCacheDrawing(false);
// Reset the drawing cache background color to fully transparent
// for the duration of this operation
int color = v.getDrawingCacheBackgroundColor();
v.setDrawingCacheBackgroundColor(0);
if (color != 0) {
v.destroyDrawingCache();
}
v.buildDrawingCache();
Bitmap cacheBitmap = v.getDrawingCache();
if (cacheBitmap == null) {
Log.e(TAG, "failed getViewBitmap(" + v + ")", new RuntimeException());
return null;
}
Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);
// Restore the view
v.destroyDrawingCache();
v.setWillNotCacheDrawing(willNotCache);
v.setDrawingCacheBackgroundColor(color);
return bitmap;
}
public boolean dispatchKeyEvent(KeyEvent event) {
return mDragging;
}
public void cancelDrag() {
endDrag();
}
private void endDrag() {
if (mDragging) {
mDragging = false;
if (mOriginator != null) {
mOriginator.setVisibility(View.VISIBLE);
}
if (mListener != null) {
mListener.onDragEnd();
}
if (mDragView != null) {
mDragView.remove();
mDragView = null;
}
}
}
public boolean onInterceptTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
if (action == MotionEvent.ACTION_DOWN) {
recordScreenSize();
}
final int screenX = clamp((int)ev.getRawX(), 0, mDisplayMetrics.widthPixels);
final int screenY = clamp((int)ev.getRawY(), 0, mDisplayMetrics.heightPixels);
switch (action) {
case MotionEvent.ACTION_MOVE:
break;
case MotionEvent.ACTION_DOWN:
mMotionDownX = screenX;
mMotionDownY = screenY;
mLastDropTarget = null;
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
if (mDragging) {
drop(screenX, screenY);
}
endDrag();
break;
}
return mDragging;
}
/**
* Sets the view that should handle move events.
*/
void setMoveTarget(View view) {
mMoveTarget = view;
}
public boolean dispatchUnhandledMove(View focused, int direction) {
return mMoveTarget != null && mMoveTarget.dispatchUnhandledMove(focused, direction);
}
public boolean onTouchEvent(MotionEvent ev) {
if (!mDragging) {
return false;
}
final int action = ev.getAction();
final int screenX = clamp((int)ev.getRawX(), 0, mDisplayMetrics.widthPixels);
final int screenY = clamp((int)ev.getRawY(), 0, mDisplayMetrics.heightPixels);
switch (action) {
case MotionEvent.ACTION_DOWN:
mMotionDownX = screenX;
mMotionDownY = screenY;
break;
case MotionEvent.ACTION_MOVE:
mDragView.move((int)ev.getRawX(), (int)ev.getRawY());
final int[] coordinates = mCoordinatesTemp;
DropTarget dropTarget = findDropTarget(screenX, screenY, coordinates);
if (dropTarget != null) {
if (mLastDropTarget == dropTarget) {
dropTarget.onDragOver(mDragSource, coordinates[0], coordinates[1], (int)mTouchOffsetX, (int)mTouchOffsetY, mDragView, mDragInfo);
}
else {
if (mLastDropTarget != null) {
mLastDropTarget.onDragExit(mDragSource, coordinates[0], coordinates[1], (int) mTouchOffsetX, (int) mTouchOffsetY, mDragView, mDragInfo);
}
dropTarget.onDragEnter(mDragSource, coordinates[0], coordinates[1], (int)mTouchOffsetX, (int)mTouchOffsetY, mDragView, mDragInfo);
}
}
else {
if (mLastDropTarget != null) {
mLastDropTarget.onDragExit(mDragSource, coordinates[0], coordinates[1], (int)mTouchOffsetX, (int)mTouchOffsetY, mDragView, mDragInfo);
}
}
mLastDropTarget = dropTarget;
break;
case MotionEvent.ACTION_UP:
if (mDragging) {
drop(screenX, screenY);
}
endDrag();
break;
case MotionEvent.ACTION_CANCEL:
cancelDrag();
}
return true;
}
private boolean drop(float x, float y) {
final int[] coordinates = mCoordinatesTemp;
final DropTarget dropTarget = findDropTarget((int) x, (int) y, coordinates);
if (dropTarget != null) {
dropTarget.onDragExit(mDragSource, coordinates[0], coordinates[1], (int)mTouchOffsetX, (int)mTouchOffsetY, mDragView, mDragInfo);
if (dropTarget.acceptDrop(mDragSource, coordinates[0], coordinates[1], (int) mTouchOffsetX, (int) mTouchOffsetY, mDragView, mDragInfo)) {
dropTarget.onDrop(mDragSource, coordinates[0], coordinates[1], (int)mTouchOffsetX, (int)mTouchOffsetY, mDragView, mDragInfo);
mDragSource.onDropCompleted((View)dropTarget, true);
}
else {
mDragSource.onDropCompleted((View)dropTarget, false);
}
return true;
}
return false;
}
private DropTarget findDropTarget(int x, int y, int[] dropCoordinates) {
final Rect r = mRectTemp;
final ArrayList<DropTarget> dropTargets = mDropTargets;
final int count = dropTargets.size();
for (int i = count - 1; i >= 0; i--) {
final DropTarget target = dropTargets.get(i);
target.getHitRect(r);
target.getLocationOnScreen(dropCoordinates);
r.offset(dropCoordinates[0] - target.getLeft(), dropCoordinates[1] - target.getTop());
if (r.contains(x, y)) {
dropCoordinates[0] = x - dropCoordinates[0];
dropCoordinates[1] = y - dropCoordinates[1];
return target;
}
}
return null;
}
private void recordScreenSize() {
((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getMetrics(mDisplayMetrics);
}
private static int clamp(int val, int min, int max) {
if (val < min) {
return min;
}
else if (val >= max) {
return max - 1;
}
else {
return val;
}
}
public void setDragListener(DragListener listener) {
mListener = listener;
}
public void addDropTarget(DropTarget target) {
mDropTargets.add(target);
}
public void removeDropTarget(DropTarget target) {
mDropTargets.remove(target);
}
}