使用WindowManager创建可拖动的悬浮按钮_JAVA_编程开发_程序员俱乐部

class="java" name="code">
private WindowManager wm;
	private View view;//浮动按钮
	/**
	 * 添加悬浮View
	 */
	protected void createFloatView() {
		int w=200;//大小
		wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
		view = getLayoutInflater().inflate(R.layout.scanball, null);
		final WindowManager.LayoutParams params = new WindowManager.LayoutParams();
		params.type=LayoutParams.TYPE_BASE_APPLICATION;//所有程序窗口的“基地”窗口，其他应用程序窗口都显示在它上面。    
		params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL|LayoutParams.FLAG_NOT_FOCUSABLE;
		params.format = PixelFormat.TRANSLUCENT;// 不设置这个弹出框的透明遮罩显示为黑色
		params.width = w;
		params.height = w;
		params.gravity = Gravity.TOP|Gravity.LEFT;
		int screenWidth = getResources().getDisplayMetrics().widthPixels;
		int screenHeight = getResources().getDisplayMetrics().heightPixels;
		params.x = screenWidth-w;
		params.y = screenHeight-w-160;
		view.setBackgroundColor(Color.TRANSPARENT);
		view.setVisibility(View.VISIBLE);
		view.setOnTouchListener(new OnTouchListener() {
			// 触屏监听
			float lastX, lastY;
			int oldOffsetX,oldOffsetY;
			int tag = 0;//悬浮球 所需成员变量
			@Override
			public boolean onTouch(View v, MotionEvent event) {
					final int action = event.getAction();
					float x = event.getX();
					float y = event.getY();
					if(tag == 0){
					   oldOffsetX= params.x; // 偏移量
					   oldOffsetY = params.y; // 偏移量
					}
					if (action == MotionEvent.ACTION_DOWN) {
						lastX = x;
						lastY = y;
					}
					else if (action == MotionEvent.ACTION_MOVE) {
						params.x += (int) (x - lastX)/3; //减小偏移量,防止过度抖动
						params.y += (int) (y - lastY)/3; //减小偏移量,防止过度抖动
						tag = 1;
						wm.updateViewLayout(view, params);
					}
					else if (action ==  MotionEvent.ACTION_UP){
						int newOffsetX = params.x;
						int newOffsetY = params.y;		
						//只要按钮一动位置不是很大,就认为是点击事件
						if(Math.abs(oldOffsetX-newOffsetX)<=20&&Math.abs(oldOffsetY-newOffsetY)<=20){
							//dosomething
							scan();
						}else{
							tag = 0;
						}
					}
					return true;
			}
		});
		
		wm.addView(view, params);
	}
	
	/**
	 * 点击浮动按钮触发事件，需要override该方法
	 */
	protected void scan(){
		
	}
	
	/**
	 * 将悬浮View从WindowManager中移除
	 */
	protected void removeFloatView() {
		if (wm != null&&view!=null) {
			wm.removeView(view);
			view = null;
			wm = null;
		}
	}