Android使用WindowManager制作一个可拖动的控件

package com.rong.activity;import com.rong.test.R;import android.content.Context;import android.graphics.Color;import android.graphics.PixelFormat;import android.util.AttributeSet;import android.view.Gravity;import android.view.MotionEvent;import android.view.View;import android.view.WindowManager;import android.widget.Button;import android.widget.RelativeLayout;public class DragView extends RelativeLayout { private WindowManager windowManager;// 用于可拖动的浮动窗口 private WindowManager.LayoutParams windowParams;// 浮动窗口的参数 private Button myButton; public DragView(Context context, AttributeSet attrs) { super(context, attrs); init(); } private void init() { View.inflate(getContext(), R.layout.layout_my, this); myButton = new Button(getContext()); myButton.setText("我的"); myButton.setBackgroundColor(Color.RED); } @Override public boolean onTouchEvent(MotionEvent event) { // 获取当前点的xy位置 int currentX = (int) event.getX(); int currentY = (int) event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN:  if (windowManager == null) {  setWindowParams(currentX, currentY);  windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);  windowManager.addView(myButton, windowParams);  }  break; case MotionEvent.ACTION_MOVE:  windowParams.x = currentX;  windowParams.y = currentY;  windowManager.updateViewLayout(myButton, windowParams);  break; case MotionEvent.ACTION_UP:  // windowManager.removeView(myButton);  break; } return true; } private void setWindowParams(int x, int y) { // 建立item的缩略图 windowParams = new WindowManager.LayoutParams(); windowParams.gravity = Gravity.TOP | Gravity.LEFT;// 这个必须加 // 得到preview左上角相对于屏幕的坐标 windowParams.x = x; windowParams.y = y; // 设置宽和高 windowParams.width = 200; windowParams.height = 200; windowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE  | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON  | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN; windowParams.format = PixelFormat.TRANSLUCENT; windowParams.windowAnimations = 0; }}

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:id="@+id/main_touchlayout"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:background="#ffffff"  android:orientation="vertical" >  <com.rong.activity.DragView    android:id="@+id/main_touchview"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:layout_centerInParent="true"    android:background="#ff0000" /></RelativeLayout>