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name Punditsdkoslkdosdkoskdo

Override Power button just like Home button

Well, I am doing something in which I want to disable all hard buttons of the device.

Hard buttons like Power, Home, Volume up, Volume down, Search, Back.

I have successfully overridden almost all buttons here except Power.

So I just want you people to see and please share some ideas so that I get can away with it.

I am getting the long press Power keyevent in onDispatchKeyEvent(), in the same way I want to catch the short click of the same. Moreover when pressing power I also tried to stop Screen off by getting the Broadcast of SCREEN_OFF and I succeeded in receiving it but I was not able to handle it.

Thanks.

Then, I had created a ReceiverScreen which receives broadcast of Screen on/off

ReceiverScreen.java

public class ReceiverScreen extends BroadcastReceiver {

    public static boolean wasScreenOn = true;

    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
            // do whatever you need to do here
            wasScreenOn = false;
        } else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
            // and do whatever you need to do here
            wasScreenOn = true;
        }
    }
}

DisableHardButton.java

public class DisableHardButton extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);
    IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
    filter.addAction(Intent.ACTION_SCREEN_OFF);
    BroadcastReceiver mReceiver = new ReceiverScreen();
    registerReceiver(mReceiver, filter);
    }

@Override
    protected void onPause() {
        // when the screen is about to turn off
        if (ScreenReceiver.wasScreenOn) {
            // this is the case when onPause() is called by the system due to a screen state change
            System.out.println("SCREEN TURNED OFF");

    } else {
        // this is when onPause() is called when the screen state has not changed
    }
    super.onPause();
}

@Override
protected void onResume() {
    // only when screen turns on
    if (!ScreenReceiver.wasScreenOn) {
        // this is when onResume() is called due to a screen state change
        System.out.println("SCREEN TURNED ON");
    } else {
        // this is when onResume() is called when the screen state has not changed
    }
    super.onResume();
}
}

Phew. This is quite a contended question, with a great deal of commentary behind it.

Let me begin by rephrasing your question a bit. If I understand clearly, you'd like to disable all physical buttons on the device for the duration of your activity. This is inclusive of the power button, which you detect by handling the ACTION_SCREEN_OFF intent. Your current (successful) workaround for this scenario is to broadcast an ACTION_SCREEN_ON, kicking the screen back to life when it's turned off, provided the host implements this correctly.

You'd now like to go the extra mile, by rendering this action unnecessary, if (and only if) you are able to catch and handle ACTION_SCREEN_OFF before it gets sent to the system. Is this possible, and if so, how?

This bears some discussion. The short version, however, is simple: this is not possible, without custom modification to your firmware or the core of the Android operating system, for a limited number of devices.

The Android system, as far as is documented, defines this as a broadcast action. Following the publish-subscribe pattern of message propagation, this message will notify all concerned parties of this action. Because this message is sent by the system, because the message stack is managed by the system, and because the message is also received by the system, your code simply isn't injected in the right place to block the reception of this message.

Furthermore, for some devices, this will be a physical switch that has no programmatic interrupt whatsoever. At best, the Android system can hope to handle for the event when it happens, which is precisely why this broadcast message is something of a special case in the service stack. To the best of my knowledge and based upon the sparse documentation on this scenario, this is why it's not an out-of-the-box, supported feature, before we consider any of the possible vectors for abuse.

Your best recourse is actually a much simpler one, if you have the ability to modify the physical hardware for the device in question: restrict access to, mangle, or otherwise disable the physical power button. In many scenarios this is undesirable, but this works in situations where your Android device is being used, for example, as a point-of-sale or a public service machine. If this is unworkable, placing physical restrictions on access to the power button may be all that's required, handling for the remainder of cases (for example, spot attempts to toggle the screen) by sending ACTION_SCREEN_ON.

Just remember, this strategy isn't foolproof. Do this competently and document the procedure well, lest you become fodder for the next 2600 exposé.

Best of luck with your application.

  • 52
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      • 1
    • Me too agreed that its not possible without any modification at firmware. @MrGomez Firstly let me tell you earlier what i get to know is you cant override the HOME button but still I had done something with it(link pasted above), so the same thing i want with Power button. Expecting some nuisance idea. I dint expect still answer but a +1 to you.
      • 1
    • @hotveryspicy Agreed. The interesting thing about the Android home button is it's not guaranteed to be physical and, indeed, it doesn't carry the same power state coupling. So, at the OS level, it can be disabled by using tricky workarounds (ie, orphan theming, TYPE_KEYGUARD, or in some cases, simply pretending the system has a physical key when it doesn't). When you have something that alters the power state in hardware, however, it becomes more difficult, bordering on solutions that are even more convoluted (if that makes sense). Thank you for your support, in any event. :)
    • Extra credit to improve this answer: does someone have a good list of devices that run Android and use physical device switches for their screen and power states? Given the open-source nature of Android, it's clear why this is a design decision, but I can find no good, current list of examples to cite here.

On the contrary to all the answers .. Check this out:


@Override
public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_POWER) {
                Log.i("", "Dispath event power");
                Intent closeDialog = new Intent(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
                sendBroadcast(closeDialog);
                return true;
        }

        return super.dispatchKeyEvent(event);
}

What it does:

Whenever the user presses the power button. We cancel the Dialog before its even seen!! :) . This works for me.. (Tested on note2)

  • 9
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Here is what I have done:

(1) Create a receiver class:

public class ScreenReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        switch (action) {
            case Intent.ACTION_SCREEN_OFF:
                BaseActivity.unlockScreen();
                break;

            case Intent.ACTION_SCREEN_ON:
                // and do whatever you need to do here
                BaseActivity.clearScreen();
        }
    }
}

(2) The two methods that are called above looked like this:

public static void unlockScreen () {
    if (current == null) return;

    Log.i( Constants.TAG, "Turning on screen ... " );

    Window window = current.getWindow();
    window.addFlags( WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD );
    window.addFlags( WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED );
    window.addFlags( WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON   );
}

public static void clearScreen () {
    if (current == null) return;

    Log.i( Constants.TAG, "Clearing screen flag when on ... " );

    Window window = current.getWindow();
    window.clearFlags( WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD );
    window.clearFlags( WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED );
    window.clearFlags( WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON   );
}

private static BaseActivity current;

@Override
protected void onResume () {
    current = this;
}

(3) In the main activity class onCreate() method register the receiver:

    IntentFilter filter = new IntentFilter( Intent.ACTION_SCREEN_ON );
    filter.addAction( Intent.ACTION_SCREEN_OFF );
    registerReceiver(new ScreenReceiver(), filter);
  • 5
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You can get to know about the Power Button press, but I dont think you will get to override it and you will be able to dismiss the dialog for power off and show something else.

Here is what I have tried,

package com.easylogs.app;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;

public class CloseSystemDialogsIntentReceiver extends BroadcastReceiver {
    public void onReceive(final Context context, final Intent intent) {
        Log.i("HERE", "------------------------------------HERE");
        Toast.makeText(context, "OFFFFFFFFFFFFFFFF",Toast.LENGTH_LONG).show();
    }
}

and declaration in Manifest as,

    <receiver android:name="CloseSystemDialogsIntentReceiver">
    <intent-filter>
            <action android:name="android.intent.action.CLOSE_SYSTEM_DIALOGS" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </receiver>
  • 2
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      • 2
    • I am able to get Power long click event in onDispatchKey(), but i want to catch short key press and have to override somehow may kinda illusion.
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
    if (event.getKeyCode() == KeyEvent.KEYCODE_POWER) {

        return true;
    }

    return super.dispatchKeyEvent(event);
}

have you tried the above code where we can handle power key event. Also have a look at this LINK which has handled power button pressed event.

  • 2
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I know its too late ,but may be helpful for other developers in future. Tested over Android N . Reference from https://stackoverflow.com/a/15828592/1065357

 @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if(!hasFocus) {
           Intent closeDialog = new Intent(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
            sendBroadcast(closeDialog);
        }
    }
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