自定義可拖拽的GridView

轉轉請注明出處 http://blog.csdn.net/u011510784/article/details/51524900

自定義可拖拽的GridView，如圖：

自定義可以拖拽的Gridview，繼承 Gridview：

public class DraggableGridView extends GridView {

		public DraggableGridView(Context context) {
			super(context);
			this.mContext = context;
	}

		public DraggableGridView(Context context, AttributeSet attrs) {
			super(context, attrs);
			this.mContext = context;
	}

}
           

重寫 onInterceptTouchEvent(MotionEvent ev) 方法

@Override
	public boolean onInterceptTouchEvent(MotionEvent ev) {
		// 攔截按下動作
		if (ev.getAction() == MotionEvent.ACTION_DOWN) {
			return setOnItemLongClickListener(ev);
		}
		return super.onInterceptTouchEvent(ev);
	}
           

處理長按時間：

public boolean setOnItemLongClickListener(final MotionEvent ev) {
		this.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
			@Override
			public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
					int arg2, long arg3) {
				        。。。
					return false;
				};
		});
		return super.onInterceptTouchEvent(ev);
	}
           

這裡主要操作是記錄長按的位置，并将長按的那個ItemView懸浮顯示，主要代碼：

int offset=5;
		ViewGroup itemView = (ViewGroup) getChildAt(dragPosition- getFirstVisiblePosition());
		itemView.destroyDrawingCache();
		itemView.setDrawingCacheEnabled(true);
		itemView.setDrawingCacheBackgroundColor(0xff6DB7ED);
		Bitmap bm = Bitmap.createBitmap(itemView.getDrawingCache(true));
		Bitmap bitmap = Bitmap.createBitmap(bm, 0, 0,
				bm.getWidth() - offset, bm.getHeight() - offset);
		startDrag(bitmap, x, y);
           

private void startDrag(Bitmap bm, int x, int y) {
		stopDrag();
		windowParams = new WindowManager.LayoutParams();
		windowParams.gravity = Gravity.TOP | Gravity.LEFT;
		windowParams.x = dragItemView.getLeft();
		windowParams.y = dragItemView.getTop()
				+ (int) (45 * Configure.screenDensity);
		windowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
		windowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
		windowParams.alpha = 0.8f;

		ImageView iv = new ImageView(getContext());
		iv.setImageBitmap(bm);
		windowManager = (WindowManager) getContext().getSystemService(
				Context.WINDOW_SERVICE);
		// 把影像ImagView添加到目前視圖中
		windowManager.addView(iv, windowParams);

		dragImageView = iv;
	}
           

然後監聽滑動事件，并相應的顯示移動的動畫效果，然後在手指擡起時結束整個過程，重新整理布局：

@Override
	public boolean onTouchEvent(MotionEvent ev) {
		if (dragImageView != null
				&& dragPosition != AdapterView.INVALID_POSITION) {
			// 控制父控件攔截事件
			getParent().requestDisallowInterceptTouchEvent(true);
			int x = (int) ev.getX();
			int y = (int) ev.getY();
			switch (ev.getAction()) {
			case MotionEvent.ACTION_MOVE:
				if (!isCountXY) {
					// 移動到哪個位置
					xtox = x - mLastX;
					ytoy = y - mLastY;
					isCountXY = true;
				}
				onDrag(x, y);
				if (!isMoving)
					onMove(x, y);
				break;
			case MotionEvent.ACTION_UP:
				stopDrag();
				onDrop(x, y);
				break;
			}
		}
		return super.onTouchEvent(ev);
	}
           

onDrag()方法用來根據手指的滑動來動态滑動我們在上面建立的那個ItemView：

private void onDrag(int x, int y) {
		// 計算位置，通過windowManager不停地更新View
		if (dragImageView != null) {
			windowParams.alpha = 0.8f;
			windowParams.x = (x - mLastX - xtox) + dragItemView.getLeft();
			windowParams.y = (y - mLastY - ytoy) + dragItemView.getTop() + 200
					+ (int) (45 * Configure.screenDensity);
			windowManager.updateViewLayout(dragImageView, windowParams);
		}
	}
           

onMove()方法用來根據手指滑動來動态滑動Gridview中的item，并且通過OnDragChangedListener接口通知Adapter進行相應的資料重新整理。

更具體的代碼實作請看源碼：

源碼下載下傳