mFloatingWindowView =  layoutInflater.inflate(R.layout.floating_window, null, false);


mFloatingWindowLayoutParams = new WindowManager.LayoutParams();

  // 设置window type
        mUserConversationWindowParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ERROR;

mUserConversationWindowParams.format = PixelFormat.TRANSLUCENT;// 设置图片格式，效果为背景透明

 // 设置Window flag
 mUserConversationWindowParams.flags =
//可使用FLAG_DISMISS_KEYGUARD选项直接解除非加锁的锁屏状态。此选项只用于最顶层的全屏幕窗口。
 WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
 
 | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL //必须 设置窗口不拦截窗口范围之外事件
 
 |WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH // 必须 设置在有FLAG_NOT_TOUCH_MODAL属性时，窗口之外事件发生时自己也获取事件

 | WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;

mWindowManager.addView(mFloatingWindowView, mFloatingWindowLayoutParams);

import android.content.Context;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.widget.LinearLayout;

/**
 * Created by KB-Shirlman on 4/26/2016.
 */
public class FloatingWindowView extends LinearLayout {
    public FloatingWindowView(Context context) {
        super(context);
    }

    public FloatingWindowView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public FloatingWindowView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
                || event.getKeyCode() == KeyEvent.KEYCODE_SETTINGS) {

if(event.getAction()==KeyEvent.ACTION_DOWN){   //按键  按下和移开会有两个不同的事件所以需要区分

closecao();   //点击返回 要执行的方法

}

} return super.dispatchKeyEvent(event); }  }