Android screen overlay example. Draws a button over other apps.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Overlay example"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.design.widget.CoordinatorLayout>

MainActivity.java

package io.sjf.overlay;

import android.annotation.TargetApi;
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "Overlay";

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

    private static int REQUEST_CODE = 1;
    private boolean checkDrawOverlayPermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            /** check if we already  have permission to draw over other apps */
            if (!Settings.canDrawOverlays(this)) {
                Log.d(TAG, "canDrawOverlays NOK");
                /** if not construct intent to request permission */
                Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
                        Uri.parse("package:" + getPackageName()));
                /** request permission via start activity for result */
                startActivityForResult(intent, REQUEST_CODE);
                return false;
            } else {
                Log.d(TAG, "canDrawOverlays OK");
            }
        }
        return true;
    }

    @Override
    @TargetApi(Build.VERSION_CODES.M)
    protected void onActivityResult(int requestCode, int resultCode,  Intent data) {
        /** check if received result code
          is equal our requested code for draw permission  */
        if (requestCode == REQUEST_CODE) {
            if (Settings.canDrawOverlays(this)) {
                startOverlayService();
            }
        }
    }

    private void startOverlayService() {
        Intent intent = new Intent(this, OverlayService.class);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            startForegroundService(intent);
        } else {
            startService(intent);
        }
    }
}

manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="io.sjf.overlay">
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
    <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"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service
            android:name=".OverlayService"
            android:exported="false"/>
    </application>
</manifest>

OverlayService.java

package io.sjf.overlay;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.PixelFormat;
import android.os.Build;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.support.v4.app.NotificationCompat;
import android.util.Log;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.view.WindowManager;
import android.widget.Button;

public class OverlayService extends Service implements OnTouchListener, OnClickListener {
    private static String TAG = "OverlayService";
    private WindowManager wm;
    private Button button;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        super.onCreate();
        if (Build.VERSION.SDK_INT >= 26) {
            String CHANNEL_ID = "channel1";
            NotificationChannel channel = new NotificationChannel(CHANNEL_ID,
                    "Overlay notification",
                    NotificationManager.IMPORTANCE_LOW);

            ((NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE))
                    .createNotificationChannel(channel);

            Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
                    .setContentTitle("adsf")
                    .setContentText("asdf1")
                    .setSmallIcon(R.drawable.ic_launcher_foreground)
                    .build();

            startForeground(1, notification);
        }

        wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

        button = new Button(this);
        button.setBackgroundResource(R.drawable.ic_button1);
        button.setText("Button");
        button.setAlpha(1);
        button.setBackgroundColor(Color.BLUE);
        button.setOnClickListener(this);

        int type = Build.VERSION.SDK_INT >= Build.VERSION_CODES.O
                ? WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY
                : WindowManager.LayoutParams.TYPE_PHONE;

        WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.WRAP_CONTENT,
                type,
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
                PixelFormat.TRANSLUCENT);
        params.gravity = Gravity.START | Gravity.TOP;
        params.x = 0;
        params.y = 0;
        wm.addView(button, params);

        return START_NOT_STICKY;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        Log.d(TAG, " ++++ On touch");
        return false;
    }

    @Override
    public void onClick(View v) {
        Log.d(TAG, " ++++ On click");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (button != null) {
            wm.removeView(button);
            button = null;
        }
    }
    
    @Override
    @Nullable
    public IBinder onBind(Intent intent) {
        return null;
    }

}

Can it move able?

@prokash447 you can control the positioning with the params.x/y passed to wm.addView here (Line 70)

when i open the setting app(system setting) the overlay does not work. why? have any solution?

Hello,

I see a blank activity that blocks touch events to home screen/ apps underneath. Are we missing any other configurations?