Android Viewを他のアプリの上に表示する

LayerService クラス

public class LayerService extends Service {
 
    private WindowManager windowManager;
    private View view;
 
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // Inflater 作成
        LayoutInflater layoutInflater = LayoutInflater.from(this);
 
        windowManager = (WindowManager) getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
 
        // Viewの作成
        WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                WindowManager.LayoutParams.WRAP_CONTENT, // 横幅
                WindowManager.LayoutParams.WRAP_CONTENT, // 高さ
                WindowManager.LayoutParams.TYPE_SYSTEM_ALERT, // 表示レイヤー　優先度
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                        | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL, // viewの動作(touch等)
                PixelFormat.TRANSLUCENT // viewを透明にする
        );
        view = layoutInflater.inflate(R.layout.overlay, null);
        windowManager.addView(view, params); // WindowManagerにViewを追加
 
        return super.onStartCommand(intent, flags, startId);
    }
 
    @Override
    public void onCreate() {
        super.onCreate();
    }
 
    @Override
    public void onDestroy() {
        super.onDestroy();
        windowManager.removeView(view); // サービス破棄時Viewを削除する
    }
 
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}
 

レイアウトファイル　overlay.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">  <!--horizontal-->

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:foreground="@color/colorPrimaryDark"
        android:text=" Overlay Test " />
</LinearLayout>
 

MainActivity

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void buttonStart_onClick(View view) {
        startService(new Intent(MainActivity.this, LayerService.class));
    }

    public void buttonStop_onClick(View view) {
        stopService(new Intent(MainActivity.this, LayerService.class));
    }
}
 

レイアウトファイル　activity_main.xml

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void buttonStart_onClick(View view) {
        startService(new Intent(MainActivity.this, LayerService.class));
    }

    public void buttonStop_onClick(View view) {
        stopService(new Intent(MainActivity.this, LayerService.class));
    }
}
 

マニフェストファイル　AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="test.shell.overlaytest04">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service android:name=".LayerService" />

    </application>

</manifest>