Android使用WindowManager构造悬浮view

一般在android显示一个View都是通过Activity的setContentView设置的，但是还有一种方法，可以直接使用WindowManager在整个应用的最上层绘制我们需要显示的view，总体的效果类似于AlertDialog的弹出效果。

使用WindowManager构造这样的一个悬浮View也比较简单，直接通过windowmanager.addView()方法即可。

package com.gearmotion.app.windowmanagermotion;

import android.content.Context;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.Button;

public class MainActivity extends AppCompatActivity implements View.OnClickListener, View.OnTouchListener {

Button mShowBtn;
Button mHideBtn;
WindowManager mWm;
LayoutInflater mLayoutInflater;
View mWindowView;

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 mShowBtn = (Button) this.findViewById(R.id.showbtn);
 mHideBtn = (Button) this.findViewById(R.id.hidebtn);
 mShowBtn.setOnClickListener(this);
 mHideBtn.setOnClickListener(this);
 init();
}

private void init() {
 mWm = (WindowManager) this.getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
 mLayoutInflater = LayoutInflater.from(this);
}

@Override
public void onClick(View v) {
 if (mShowBtn.hashCode() == v.hashCode()) { //显示WindowManager
  show();
 }
 if (mHideBtn.hashCode() == v.hashCode()) { //隐藏windowmanager
  hide();
 }
}

private void show() {
 mWindowView = mLayoutInflater.inflate(R.layout.item_layout, null);
 View popView = mWindowView.findViewById(R.id.root);
 //设置popView的触摸事件，以便点击空白区域的时候使悬浮view消失
 popView.setOnTouchListener(this);
 WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
 //窗口类型同系统弹出框
 lp.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
 //响应输入法
 //lp.flags = WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM;
 //透明层
 lp.format = PixelFormat.TRANSPARENT;
 lp.width = WindowManager.LayoutParams.MATCH_PARENT;
 lp.height = WindowManager.LayoutParams.MATCH_PARENT;
 lp.gravity = Gravity.CENTER_VERTICAL;
 mWm.addView(mWindowView, lp);
}

private void hide() {
 if (mWindowView != null && mWindowView.getParent() != null) {
  mWm.removeView(mWindowView);
 }
}

@Override
public boolean onTouch(View v, MotionEvent event) {
 int x = (int) event.getX();
 int y = (int) event.getY();
 //获取主view的可视区域
 Rect globalRect = new Rect();
 //获取悬浮view的可视区域
 Rect tmpRect = new Rect();
 v.getGlobalVisibleRect(globalRect);
 View child = ((ViewGroup) v).getChildAt(0);
 child.getHitRect(tmpRect);
 if (!tmpRect.contains(x, y) && globalRect.contains(x, y)) {
  hide();
 }
 return true;
}
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">

<Button
 android:id="@+id/showbtn"
 android:layout_width="match_parent"
 android:layout_height="50dp"
 android:gravity="center"
 android:text="show" />

<Button
 android:id="@+id/hidebtn"
 android:layout_width="match_parent"
 android:layout_height="50dp"
 android:gravity="center"
 android:text="hide" />
</LinearLayout>

item_layout.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="@+id/root"
android:orientation="vertical">

<TextView
 android:layout_width="match_parent"
 android:layout_height="50dp"
 android:text="I am WindowManager layout view"
 android:textSize="20sp"
 android:gravity="center"
 android:layout_gravity="center"
 android:background="#FFF8DC"
 android:textColor="#7AC5CD"/>
</LinearLayout>

实现效果如下：