如何在 Android GridView 中实现拖放功能。任何人都可以请提供相同的最佳链接吗？
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4 回答
6
于 2012-12-31T12:31:52.240 回答
3
这是我在 android 拖放 android 2.2 中见过的最好的例子。您使用的是哪个版本？
于 2012-10-02T12:50:16.250 回答
1
使用 WindowManager 尝试另一种方法：
package com.example.cooldraganddrop;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.PixelFormat;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.ImageView;
public class CoolDragAndDropGridView extends SpanVariableGridView implements `View.OnTouchListener {`
private static final int ITEM_HOVER_DELAY = 450;
private int mDragPointX;
private int mDragPointY;
private int mDragOffsetX;
private int mDragOffsetY;
private int mDragPosition = AdapterView.INVALID_POSITION;
private int mDropPosition = AdapterView.INVALID_POSITION;
private int mCurrentPosition = AdapterView.INVALID_POSITION;
private Runnable mDelayedOnDragRunnable = null;
ScrollingStrategy mScrollingStrategy = null;
WindowManager mWindowManager = null;
WindowManager.LayoutParams mWindowParams = null;
private ImageView mDragImageView = null;
private boolean mDragAndDropStarted = false;
private DragAndDropListener mDragAndDropListener = null;
private OnTrackTouchEventsListener mOnTrackTouchEventsListener = null;
public static interface OnTrackTouchEventsListener {
void trackTouchEvents(final MotionEvent motionEvent);
};
public static interface DragAndDropListener {
void onDragItem(int from);
void onDraggingItem(int from, int to);
void onDropItem(int from, int to);
boolean isDragAndDropEnabled(int position);
}
public CoolDragAndDropGridView(Context context) {
super(context);
initialize();
}
public CoolDragAndDropGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initialize();
}
public CoolDragAndDropGridView(Context context, AttributeSet attrs) {
super(context, attrs);
initialize();
}
private void initialize() {
setOnTouchListener(this);
setChildrenDrawingOrderEnabled(true);
}
public void startDragAndDrop() {
mDragAndDropStarted = true;
}
public void setDragAndDropListener(DragAndDropListener dragAndDropListener) {
mDragAndDropListener = dragAndDropListener;
}
private void destroyDragImageView() {
if (mDragImageView != null) {
mWindowManager.removeView(mDragImageView);
BitmapDrawable bitmapDrawable = (BitmapDrawable) mDragImageView.getDrawable();
if (bitmapDrawable != null) {
final Bitmap bitmap = bitmapDrawable.getBitmap();
if (bitmap != null && !bitmap.isRecycled()) {
bitmap.recycle();
}
}
mDragImageView.setImageDrawable(null);
mDragImageView = null;
}
}
private ImageView createDragImageView(final View v, final int x, final int y) {
v.destroyDrawingCache();
v.setDrawingCacheEnabled(true);
Bitmap bm = Bitmap.createBitmap(v.getDrawingCache());
mDragPointX = x - v.getLeft();
mDragPointY = y - v.getTop();
mWindowParams = new WindowManager.LayoutParams();
mWindowParams.gravity = Gravity.TOP | Gravity.LEFT;
mWindowParams.x = x - mDragPointX + mDragOffsetX;
mWindowParams.y = y - mDragPointY + mDragOffsetY;
mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;
mWindowParams.format = PixelFormat.TRANSLUCENT;
mWindowParams.alpha = 0.7f;
mWindowParams.windowAnimations = 0;
ImageView iv = new ImageView(getContext());
iv.setBackgroundColor(Color.parseColor("#ff555555"));
iv.setImageBitmap(bm);
mWindowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);// "window"
mWindowManager.addView(iv, mWindowParams);
return iv;
}
private void startDrag(final int x, final int y) {
final View v = getChildAt(mDragPosition);
destroyDragImageView();
mDragImageView = createDragImageView(v, x, y);
v.setVisibility(View.INVISIBLE);
if (mDragAndDropListener != null) {
mDragAndDropListener.onDragItem(mDragPosition);
}
}
@Override
protected int getChildDrawingOrder(int childCount, int i) {
if (mCurrentPosition == -1)
return i;
else if (i == childCount - 1)
return mCurrentPosition;
else if (i >= mCurrentPosition)
return i + 1;
return i;
}
private void onDrop() {
destroyDragImageView();
removeCallbacks(mDelayedOnDragRunnable);
View v = getChildAt(mDropPosition);
v.setVisibility(View.VISIBLE);
v.clearAnimation();
if (mDragAndDropListener != null && mDropPosition != AdapterView.INVALID_POSITION) {
mDragAndDropListener.onDropItem(mDragPosition, mDropPosition);
}
mDragPosition = mDropPosition = mCurrentPosition = AdapterView.INVALID_POSITION;
mDragAndDropStarted = false;
}
public void setScrollingStrategy(ScrollingStrategy scrollingStrategy) {
mScrollingStrategy = scrollingStrategy;
}
private void onDrag(final int x, final int y) {
if (mScrollingStrategy != null && mScrollingStrategy.performScrolling(x, y, this)) {
removeCallbacks(mDelayedOnDragRunnable);
return;
}
final int tempDropPosition = pointToPosition(mCurrentPosition, x, y);
if (mDragAndDropListener != null && mDropPosition != tempDropPosition && tempDropPosition != AdapterView.INVALID_POSITION) {
removeCallbacks(mDelayedOnDragRunnable);
if (mDragAndDropListener.isDragAndDropEnabled(tempDropPosition)) {
mDropPosition = tempDropPosition;
mDelayedOnDragRunnable = new Runnable() {
@Override
public void run() {
mDragAndDropListener.onDraggingItem(mCurrentPosition, tempDropPosition);
performDragAndDropSwapping(mCurrentPosition, tempDropPosition);
final int nextDropPosition = pointToPosition(tempDropPosition, x, y);
if (nextDropPosition == AdapterView.INVALID_POSITION) {
mCurrentPosition = mDropPosition = tempDropPosition;
}
}
};
postDelayed(mDelayedOnDragRunnable, ITEM_HOVER_DELAY);
} else {
mDropPosition = mDragPosition;
}
}
if (mDragImageView != null) {
mWindowParams.x = x - mDragPointX + mDragOffsetX;
mWindowParams.y = y - mDragPointY + mDragOffsetY;
mWindowManager.updateViewLayout(mDragImageView, mWindowParams);
}
}
public void setOnTrackTouchEventListener(OnTrackTouchEventsListener onTrackTouchEventsListener) {
mOnTrackTouchEventsListener = onTrackTouchEventsListener;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
if (mOnTrackTouchEventsListener != null) {
mOnTrackTouchEventsListener.trackTouchEvents(event);
}
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
if (mDragAndDropListener != null && mDragAndDropStarted) {
mDragAndDropStarted = false;
getParent().requestDisallowInterceptTouchEvent(true);
return launchDragAndDrop(event);
}
break;
default:
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mDragAndDropStarted = false;
getParent().requestDisallowInterceptTouchEvent(false);
break;
}
return super.onInterceptTouchEvent(event);
}
private boolean launchDragAndDrop(final MotionEvent event) {
final int x = (int) event.getX();
final int y = (int) event.getY();
mCurrentPosition = mDragPosition = mDropPosition = pointToPosition(mDragPosition, x, y);
if (mDragPosition != AdapterView.INVALID_POSITION && mDragAndDropListener.isDragAndDropEnabled(mDragPosition)) {
mDragOffsetX = (int) (event.getRawX() - x);
mDragOffsetY = (int) (event.getRawY() - y);
startDrag(x, y);
return true;
}
return false;
}
@Override
public boolean onTouch(View view, MotionEvent event) {
if (mDragPosition != AdapterView.INVALID_POSITION && mDragImageView != null) {
final int x = (int) event.getX();
final int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE:
mDragOffsetX = (int) (event.getRawX() - x);
mDragOffsetY = (int) (event.getRawY() - y);
onDrag(x, y);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
onDrop();
resetLongClickTransition();
getParent().requestDisallowInterceptTouchEvent(false);
return false;
default:
}
return true;
}
return false;
}
}
使用这种拖放方法的示例在这里
于 2013-12-10T06:34:21.367 回答