Android悬浮窗口

一、AndroidManifest添加权限：

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

二、新建一个悬浮窗口的布局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ImageView
        android:id="@+id/image_test"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:src="@drawable/ic_launcher_background"/>
</RelativeLayout>

三、悬浮窗口通过Service来实现

public class SuspensionService extends Service {

    private WindowManager mWindowManager;
    private WindowManager.LayoutParams mLayoutParams;
    private View mView;
    private ImageView mImageView;

    public SuspensionService() {
    }

    @SuppressLint("ClickableViewAccessibility")
    @Override
    public void onCreate() {
        super.onCreate();
        mView = LayoutInflater.from(this).inflate(R.layout.suspension_window_layout,null);
        //获取系统服务WINDOW_SERVICE
        mWindowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
        mLayoutParams=new WindowManager.LayoutParams();
        mLayoutParams.type= WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;
        //FLAG_NOT_FOCUSABLE设置浮动窗口不可聚焦
        mLayoutParams.flags= WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE|WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL;
        mLayoutParams.width=700;
        mLayoutParams.height=350;
        //将悬浮窗控件加入到屏幕
        mWindowManager.addView(mView,mLayoutParams);
        mImageView = mView.findViewById(R.id.image_test);
        //监听对悬浮窗的操作
        mImageView.setOnTouchListener(new View.OnTouchListener() {
            int lastX = 0;
            int lastY = 0;
            int paramX = 0;
            int paramY = 0;
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent) {
                switch (motionEvent.getAction()) {
                    case MotionEvent.ACTION_DOWN:
                        //MotionEvent.getX()：触摸点的View从触摸点到它最左侧的距离
                        //MotionEvent.getY()：触摸点的View从触摸点到它最上侧的距离
                        //MotionEvent.getRawX()：触摸点的View从触摸点到屏幕最左侧的距离
                        //MotionEvent.getRawY()：触摸点的View从触摸点到屏幕最上侧的距离
                        lastX = (int) motionEvent.getRawX();
                        lastY = (int) motionEvent.getRawY();
                        paramX = mLayoutParams.x;
                        paramY = mLayoutParams.y;
                        break;
                    case MotionEvent.ACTION_MOVE:
                        int dx = (int) motionEvent.getRawX() - lastX;
                        int dy = (int) motionEvent.getRawY() - lastY;
                        mLayoutParams.x = paramX + dx;
                        mLayoutParams.y = paramY + dy;
                        mWindowManager.updateViewLayout(mView,mLayoutParams);
                        break;
                }
                return true;
            }
        });
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }
}

四、在MainActivity中申请权限并启动Service

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //申请是否允许显示在其他应用的上层的权限，用户手动设置
        Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
        intent.setData(Uri.parse("package:" + getPackageName()));
        startActivityForResult(intent, 100);

        //通过点击按钮来启动服务
        Button button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //启动服务打开悬浮窗口
                startService(new Intent(MainActivity.this,SuspensionService.class));
            }
        });
    }
}