android – Detect power button long press-ThrowExceptions

Exception or error:

I’ve been reading some posts here on Stackoverflow, and I didn’t find a good solution, I’m wondering if it’s possible to detect when the user long press the power button when trying to power off the device, I’d like to know if you can detect that event, and let or not show that dialog where appears (Restart, Shut Down, etc…)

I’ve tried this:

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
        Toast.makeText(MainActivity.this, event.getKeyCode(), Toast.LENGTH_SHORT).show();
    return true;
}

but it doesn’t show up, also it should work as a service, I mean that the app can or not be opened to show that toast.

EDIT

This is how I put the onCloseSystemDialog

//home or recent button
public void onCloseSystemDialogs(String reason) {
    if ("globalactions".equals(reason)) {
        Toast.makeText(PowerButtonService.this, "yaps", Toast.LENGTH_SHORT).show();
        Intent i= new Intent(getBaseContext(), Demo.class);
        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        getApplication().startActivity(i);
    //} else if ("homekey".equals(reason)) {
        //home key pressed
    //} else if ("recentapss".equals(reason)) {
        // recent apps button clicked
    }
}

It works fine, but only when the device is unlocked, when the device is locked isn’t showing anything.

Also I’m trying to figure out how to remove the dialog when the user click powerbutton I tried this :

getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);

But if I want to show it again, how can I do it?

How to solve:

Sharing my method to do what you would like to achieve.

Basically, what it does is

  1. Asking for system permission to draw overlay (This is not a normal or vulnerable permission). This is not a user permission, so You should really know, what you are doing, by asking for it.

    public class MainActivity extends AppCompatActivity {
    
        public final static int REQUEST_CODE = 10101;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            if (checkDrawOverlayPermission()) {
                startService(new Intent(this, PowerButtonService.class));
            }
        }
    
        public boolean checkDrawOverlayPermission() {
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
                return true;
            }
            if (!Settings.canDrawOverlays(this)) {
                /** 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 {
                return true;
            }
        }
    
        @Override
        @TargetApi(Build.VERSION_CODES.M)
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            if (requestCode == REQUEST_CODE) {
                if (Settings.canDrawOverlays(this)) {
                    startService(new Intent(this, PowerButtonService.class));
                }
            }
        }
    }
    
  2. Starting a service and adds a special view to WindowManager

  3. Waiting for an action inside View‘s onCloseSystemDialogs method.

    public class PowerButtonService extends Service {
    
        public PowerButtonService() {
    
        }
    
        @Override
        public void onCreate() {
            super.onCreate();
            LinearLayout mLinear = new LinearLayout(getApplicationContext()) {
    
                //home or recent button
                public void onCloseSystemDialogs(String reason) {
                    if ("globalactions".equals(reason)) {
                        Log.i("Key", "Long press on power button");
                    } else if ("homekey".equals(reason)) {
                        //home key pressed
                    } else if ("recentapps".equals(reason)) {
                        // recent apps button clicked
                    }
                }
    
                @Override
                public boolean dispatchKeyEvent(KeyEvent event) {
                    if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
                        || event.getKeyCode() == KeyEvent.KEYCODE_VOLUME_UP
                        || event.getKeyCode() == KeyEvent.KEYCODE_VOLUME_DOWN
                        || event.getKeyCode() == KeyEvent.KEYCODE_CAMERA
                        || event.getKeyCode() == KeyEvent.KEYCODE_POWER) {
                        Log.i("Key", "keycode " + event.getKeyCode());
                    }
                    return super.dispatchKeyEvent(event);
                }
            };
    
            mLinear.setFocusable(true);
    
            View mView = LayoutInflater.from(this).inflate(R.layout.service_layout, mLinear);
            WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
    
            //params
           final WindowManager.LayoutParams params;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
    
        params = new WindowManager.LayoutParams(
                100,
                100,
                WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,
                WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                        | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
                        | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.TRANSLUCENT);
    } else {
        params = new WindowManager.LayoutParams(
                100,
                100,
                WindowManager.LayoutParams.TYPE_PHONE,
                WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                        | WindowManager.LayoutParams.FLAG_FULLSCREEN
                        | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
                        | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
                PixelFormat.TRANSLUCENT);
    }
            params.gravity = Gravity.LEFT | Gravity.CENTER_VERTICAL;
            wm.addView(mView, params);
        }
    
        @Override
        public IBinder onBind(Intent intent) {
            return null;
        }
    }
    

Manifest:

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

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        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=".PowerButtonService"
            android:enabled="true"
            android:exported="true">
        </service>

    </application>

</manifest>

service_layout:

<?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="match_parent"
    android:orientation="vertical">

</LinearLayout>

###

I see many answers trying to hookin to the powerbutton. However, wouldn’t it be more easy to listen for the shutdown event? I’m not sure if this fits your need, but it seems like it.

Simply register a Broadcastreceiver to the following action(s):

<receiver android:name=".ShutdownReceiver">
    <intent-filter>
        <action android:name="android.intent.action.ACTION_SHUTDOWN" />
        <action android:name="android.intent.action.QUICKBOOT_POWEROFF" />
    </intent-filter>
</receiver>

Don’t forget to add the following permission:

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

###

This simple solution works:

    @Override
public boolean dispatchKeyEvent(KeyEvent event) {
    int keyPressed = event.getKeyCode();
    if(keyPressed==KeyEvent.KEYCODE_POWER){
        Log.d("###","Power button long click");
        Toast.makeText(MainActivity.this, "Clicked: "+keyPressed, Toast.LENGTH_SHORT).show();
        return true;}
    else
        return super.dispatchKeyEvent(event);
}

If you want to stop system pop-up, use the onWindowFocusChangedmethod specified in one of the answers below.

The output will show the toast with “Clicked:26” as attached below.enter image description here

###

Go with this

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

And when you want to capture that event do this

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_POWER) {
        // this is method which detect press even of button
        event.startTracking(); // Needed to track long presses
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

@Override
public boolean onKeyLongPress(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_POWER) {
        // Here we can detect long press of power button
        return true;
    }
    return super.onKeyLongPress(keyCode, event);
}

It can be done with broadcast receiver. see this answer

###

For Long Press…. Please Try this…

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.WindowManager;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class demo extends Activity {


    private final List<Integer> blockedKeys = new ArrayList<>(Arrays.asList(KeyEvent.KEYCODE_VOLUME_DOWN, KeyEvent.KEYCODE_VOLUME_UP, KeyEvent.KEYCODE_POWER));


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
        setContentView(R.layout.demo);


    }

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if (!hasFocus) {
            // Close every kind of system dialog
            Intent closeDialog = new Intent(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
            sendBroadcast(closeDialog);
            Toast.makeText(demo.this, "Your LongPress Power Button", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onBackPressed() {
        // nothing to do here
        // … really
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (blockedKeys.contains(event.getKeyCode())) {


            return true;
        } else {

            return super.dispatchKeyEvent(event);
        }
    }
}

Long Press Button Of power show toast for test…

enter image description here

###

Try this :

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
    if (event.getKeyCode() == KeyEvent.KEYCODE_POWER) {
        Intent i = new Intent(this, ActivitySetupMenu.class);
        startActivity(i);
        return true;
    }

    return super.dispatchKeyEvent(event);
}

###

The method used above by R. Zagórski worked for me very well for a long time, but from some revision of Android 9 the onCloseSystemDialogs method stopped receiving “globalactions”.

As a workaround, my app is already using Accessibility. From inside the AccessibilityService you can add this code in onAccessibilityEvent

@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
    Log.i(TAG,"Accessibilityevent");
    if (event == null || event.getPackageName()==null||event.getClassName()==null)
        return;


    if (event.getClassName().toString().contains("globalactions")){
        //TRIGGER YOUR CODE HERE

    }
        ....

Note that were I put the comment “TRIGGER YOUR CODE HERE” I actually just call the same code that was previously in onCloseSystemDialogs.

Note that so far this is only tested to be working on a Pixel 2 running latest Android. I do not have any other phones running a recent enough version so can’t test if the solution is sufficiently generic across phones.

###

From Skizo-ozᴉʞS question, what I understand, you actually want to prevent the behavior of the power button and that can’t be done. just like the home button pressed some events in android can’t be prevented to avoid people having apps they can’t quit.

###

You can catch the power button event by overriding onKeyDown method

@Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_POWER) {
            Log.e("key","long");
            /*//disable the system dialog
            Intent closeDialog = new Intent(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
            sendBroadcast(closeDialog);*/
            Toast.makeText(getApplicationContext(),"Power",Toast.LENGTH_SHORT).show();
        }
        return super.onKeyDown(keyCode, event);
    }

As my knowledge we can’t do this outside activity (such as background service)

###

The accepted answer works flawlessly till Android Oreo but not in Android P.
To make it work in android P you’ll need to use Accessibility Service

Service Class

import android.accessibilityservice.AccessibilityService;
import android.util.Log;
import android.view.accessibility.AccessibilityEvent;

import com.bm.yucasa.Utils.LocationSetup;

import static com.bm.yucasa.controller.AppController.TAG;

public class PowerServiceTwo extends AccessibilityService {
    @Override
    public void onAccessibilityEvent(AccessibilityEvent event) {
        Log.i(TAG,"Accessibilityevent");
        if (event == null || event.getPackageName()==null||event.getClassName()==null)
            return;


        if (event.getClassName().toString().contains("globalactions")){
            LocationSetup locationSetup = 
LocationSetup.getInstance(PowerServiceTwo.this);
            if (locationSetup.isConnected) {
                locationSetup.startOnDemandLocationUpdates(false, "0");
            } else {

                //Toast.makeText(getApplicationContext(), "please check gps", Toast.LENGTH_SHORT).show();
            }

        }
    }

    @Override
    public void onInterrupt() {

    }
}

As you cannot use startService() method to start an Accessibility Service,

So here it is how you can enable it.

Intent openSettings = new Intent(Settings.ACTION_ACCESSIBILITY_SETTINGS);
openSettings.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(openSettings);

###

Try this :

 @Override
   public boolean onKeyLongPress( int keyCode, KeyEvent event ) {
     if( keyCode == KeyEvent.KEYCODE_POWER ) {
       //Handle what you want in long press.

       return true;
     }
     return super.onKeyLongPress( keyCode, event );
   }

Add this in Manifest :

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

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