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Detect home button press in android

This has been driving me nuts for a while now.

Is there any way of reliably detecting if the home button has been pressed in an android application?

Failing that, is there a robust way of telling what caused an activity to go into onPause? i.e Can we detect if it was caused by a new activity launching or by pressing back/home.

One suggestion I have seen is to override onPause() and call isFinishing() but this will return false when pressing the home button just as it would if a new activity is starting so this fails to distinguish between the two.

Any help much appreciated.

** Update** : Thanks to @android-hungry for this link: https://nishandroid.blogspot.com/

Overiding the following method:

@Override
public void onAttachedToWindow() {
    super.onAttachedToWindow();
    this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);           
}

Then the following event WILL get fired for home button presses:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {     

    if(keyCode == KeyEvent.KEYCODE_HOME)
    {
       //The Code Want to Perform. 
    }
});

I'm not sure if there are any side effects with this line:

this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);   

So it would seem that contrary to popular belief, you can in fact listen out for the home key. Worryingly, you can return false and have the home key do nothing.

Update: As expected, there are some side affects with this - it seems that embedded videos and google maps are not visible with this mode enabled.

Update: Supposedly this hack no longer works as of Android 4.0 onwards

My problem wasn't to disguise between back and home -key but I wanted to finish application on both cases. Which I did using Activity.onUserLeaveHint().
The only problem is onUserLeaveHint() will also fire when I start an activity from said activity, I only want to know if back or home has been pressed. Thanks for suggestion though
That's true, but unfortunately, as far as I know, it's the only place to receive any information on Home -key usage. Making it more of a problem to harvest out false -positives, out of many can be recognized easily, but still making easy sounding task rather complicated.
@DeanWild: did u read this: nisha113a5.blogspot.com
TYPE_KEYGUARD constant was removed from WindowManager.LayoutParams in Android 5.0

M
Md. Asaduzzaman Noor

Following code works for me :)

HomeWatcher mHomeWatcher = new HomeWatcher(this);
mHomeWatcher.setOnHomePressedListener(new OnHomePressedListener() {
    @Override
    public void onHomePressed() {
        // do something here...
    }
    @Override
    public void onHomeLongPressed() {
    }
});
mHomeWatcher.startWatch();
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;

public class HomeWatcher {

    static final String TAG = "hg";
    private Context mContext;
    private IntentFilter mFilter;
    private OnHomePressedListener mListener;
    private InnerReceiver mReceiver;

    public HomeWatcher(Context context) {
        mContext = context;
        mFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
    }

    public void setOnHomePressedListener(OnHomePressedListener listener) {
        mListener = listener;
        mReceiver = new InnerReceiver();
    }

    public void startWatch() {
        if (mReceiver != null) {
            mContext.registerReceiver(mReceiver, mFilter);
        }
    }

    public void stopWatch() {
        if (mReceiver != null) {
            mContext.unregisterReceiver(mReceiver);
        }
    }

    class InnerReceiver extends BroadcastReceiver {
        final String SYSTEM_DIALOG_REASON_KEY = "reason";
        final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions";
        final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
        final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";

        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
                String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
                if (reason != null) {
                    Log.e(TAG, "action:" + action + ",reason:" + reason);
                    if (mListener != null) {
                        if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
                            mListener.onHomePressed();
                        } else if (reason.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
                            mListener.onHomeLongPressed();
                        }
                    }
                }
            }
        }
    }
}
public interface OnHomePressedListener {
    void onHomePressed();
    void onHomeLongPressed();
}

Your onHomeLongPressed actually seems to correspond to the opening of the "Recents" system activity. On my phone, that's triggered by pressing the recents button next to the home button, so your code's assumption about it being a home long press isn't always correct.
why it don't work for me, i did exact same except registered the broadcast through manifest.
Registered in application class, Working so far.. +1, I wonder whats the catch? I mean, what original case would we be missing.. :^)
sometimes intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY); return null. I would like to know what it's happening ??
The long press reason is now called final String SYSTEM_DIALOG_REASON_LONG_PRESS = "assist"
A
AL̲̳I

This is an old question but it might help someone.

@Override
protected void onUserLeaveHint()
{
    Log.d("onUserLeaveHint","Home button pressed");
    super.onUserLeaveHint();
}

According to the documentation, the onUserLeaveHint() method is called when the user clicks the home button OR when something interrupts your application (like an incoming phone call).

This works for me.. :)


Not Correct !!! That is worked at home button pressed but it is also worked when Swiching Activity with Intent!!
This will execute before onStop() always, even if other activity comes on the top or user forcefully leave the activity or clicking home button...
@NikunjParadva You can use onBackPressed() method in other activities to solve this issue.
J
Jave

It is impossible to detect and/or intercept the HOME button from within an Android app. This is built into the system to prevent malicious apps that cannot be exited.


check the accepted answer, it is possible. Not tested on many devices yet though.
Yeah... crashed app on mine.
what about launchers/home replacement apps? I'm building one and I want to go to the first screen when the users clicks home
For Launchers use this: @Override protected void onNewIntent(Intent intent) { super.onNewIntent(intent); /*Do what you want*/ }
@lisovaccaro launcher and or home replacements are still not supported by google (src diane hackborn) and therefore you can't prevent the user to click the homebutton. You can still, add your view as a system alert dialog, which will overlay everything. But the home button clicks will go through it.
B
Blackhex

I needed to start/stop background music in my application when first activity opens and closes or when any activity is paused by home button and then resumed from task manager. Pure playback stopping/resuming in Activity.onPause() and Activity.onResume() interrupted the music for a while, so I had to write the following code:

@Override
public void onResume() {
  super.onResume();

  // start playback here (if not playing already)
}

@Override
public void onPause() {
  super.onPause();

  ActivityManager manager = (ActivityManager) this.getSystemService(Activity.ACTIVITY_SERVICE);
  List<ActivityManager.RunningTaskInfo> tasks = manager.getRunningTasks(Integer.MAX_VALUE);
  boolean is_finishing = this.isFinishing();
  boolean is_last = false;
  boolean is_topmost = false;
  for (ActivityManager.RunningTaskInfo task : tasks) {
    if (task.topActivity.getPackageName().startsWith("cz.matelier.skolasmyku")) {
      is_last = task.numRunning == 1;
      is_topmost = task.topActivity.equals(this.getComponentName());
      break;
    }
  }

  if ((is_finishing && is_last) || (!is_finishing && is_topmost && !mIsStarting)) {
    mIsStarting = false;
    // stop playback here
  }
}

which interrupts the playback only when application (all its activities) is closed or when home button is pressed. Unfortunatelly I didn't manage to change order of calls of onPause() method of the starting activity and onResume() of the started actvity when Activity.startActivity() is called (or detect in onPause() that activity is launching another activity other way) so this case have to be handled specially:

private boolean mIsStarting;

@Override
public void startActivity(Intent intent) {
  mIsStarting = true;
  super.startActivity(intent);
}

Another drawback is that this requires GET_TASKS permission added to AndroidManifest.xml:

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

Modifying this code that it only reacts on home button press is straighforward.


N
Napolean

Override onUserLeaveHint() in the activity. There will never be any callback to the activity when a new activity comes over it or user presses back press.


it is also called also when going from one activity to another within the app
B
Basheer Kohli

onUserLeaveHint();

override this activity class method.This will detect the home key click . This method is called right before the activity's onPause() callback.But it will not be called when an activity is interrupted like a in-call activity comes into foreground, apart from that interruptions it will call when user click home key.

@Override
protected void onUserLeaveHint() {
    super.onUserLeaveHint();
    Log.d(TAG, "home key clicked");
}

R
Renaud C.

Since API 14 you can use the function onTrimMemory() and check for the flag TRIM_MEMORY_UI_HIDDEN. This will tell you that your Application is going to the background.

So in your custom Application class you can write something like:

override fun onTrimMemory(level: Int) {
    if (level == TRIM_MEMORY_UI_HIDDEN) {
        // Application going to background, do something
    }
}

For an in-depth study of this, I invite you to read this article: http://www.developerphil.com/no-you-can-not-override-the-home-button-but-you-dont-have-to/


Good article - useful alternative that probably does what most people need
Nice solution. Do you know how to reset the flag when the application returns from the background? For instance if I create a boolean isInBackground, I would want to reset it to once we return from the background.
l
lalosoft

Try to create a counter for each screen. If the user touch HOME, then the counter will be zero.

public void onStart() {
  super.onStart();
  counter++;
}

public void onStop() {
  super.onStop();
  counter--;    
  if (counter == 0) {
      // Do..
  }
}

If you mean global application counter it will be zero in a moment when one activity is being moved to back stack and another is being moved to top or when top ativity is finished and back stack activity is being moved to top which is the usual place when you want to react on home button press. If you mean activity-wide counter it will be zero any time the activity is not visible (not necessarily caused by home button press). The only solution would be to postpone your reaction using timer to skip this transition but the necessary delay may not be predictable or desirable.
V
Vito

You might consider a solution by Andreas Shrade in his post on How-To Create a Working Kiosk Mode in Android. It's a bit hacky, but given the reasons that interception of the home button is prevented it has to be ;)


J
Josh

Since you only wish for the root activity to be reshown when the app is launched, maybe you can get this behavior by changing launch modes, etc. in the manifest?

For instance, have you tried applying the android:clearTaskOnLaunch="true" attribute to your launch activity, perhaps in tandem with android:launchMode="singleInstance"?

Tasks and Back Stack is a great resource for fine-tuning this sort of behavior.


This would seem like the most elegant solution but I have found it to be quite unreliable. After a few open/close/pause cycles the app will start to just resume rather than restart completely
M
Moshe Rabaev

I had this problem, and since overriding the onKeyDown() method didn't accomplish anything because of the underlying android system didn't call this method, I solved this with overriding onBackPressed(), and I had a boolean value set there to false, because I pressed back, let me show you what I mean in code:

import android.util.Log;
public class HomeButtonActivity extends Activity {
    boolean homePressed = false;
    // override onCreate() here.

    @Override
    public void onBackPressed() {
        homePressed = false; // simply set homePressed to false
    }

    @Overide
    public void onResume() {
        super.onResume();
        homePressed = true; // default: other wise onBackPressed will set it to false
    }

    @Override
    public void onPause() {
        super.onPause();
        if(homePressed) { Log.i("homePressed", "yay"); }
    }

So the reason why this worked is because the only way to navigate outside this activity is by pressing back or home so if back was pressed then i know the cause wasn't home, but otherwise the cause was home, therefore i set the default boolean value for homePressed to be true. However this will only work with a single activity instance in your application because otherwise you have more possibilities to cause the onPause() method to be called.


in fact when you go to another activity, the onpause method is called
That's why i explicitly stated that this will only work if your application only incorporates a single activity!
And what if multiple unrelated activites are running at the same time, and the user is simply switching between them? Modern Android devices support multi-tasking. With this code, it looks like switching back to your app would set homePressed to true, and then switching to another app would think Home was pressed when it really wasn't.
A
Alexander Cavalheiro Becker

Recently I was trying to detect the home press button, because I needed it to do the same as the method "onBackPressed()". In order to do this, I had to override the method "onSupportNavigateUp()" like this:

override fun onSupportNavigateUp(): Boolean {
    onBackPressed()
    return true
}

It worked perfectly. =)


S
Stephan John

https://i.stack.imgur.com/9VWqU.png


a
ademar111190

An option for your application would be to write a replacement Home Screen using the android.intent.category.HOME Intent. I believe this type of Intent you can see the home button.

More details:

http://developer.android.com/guide/topics/intents/intents-filters.html#imatch


interesting idea but a little long winded and not as elegant as I would have hoped for
A
Andi Jay

It's a bad idea to change the behavior of the home key. This is why Google doesn't allow you to override the home key. I wouldn't mess with the home key generally speaking. You need to give the user a way to get out of your app if it goes off into the weeds for whatever reason.

I'd image any work around will have unwanted side effects.


You are absolutely spot on but some clients won't take no for an answer and don't understand why they shouldn't break the guidelines.
The problem is that even if you don't want to chage home button behaviour, you occasionally have to react differently on the situation that application is moved to back due to home button press differently than on the situation that you current activity is paused for wathever reason. The same problem is with the fact that Application.onDestroy() cannot be used for poduction builds. Such examples is pausing a game when user hides the appication, stopping background music, etc.
A
Aditya

Jack's answer is perfectly working for click event while longClick is considering is as menu button click.

By the way, if anyone is wondering how to do via kotlin,

class HomeButtonReceiver(private var context: Context,private var listener: OnHomeButtonClickListener) {
    private val mFilter: IntentFilter = IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)
    private var mReceiver: InnerReceiver = InnerReceiver()

    fun startWatch() {
        context.registerReceiver(mReceiver, mFilter)
    }

    fun stopWatch() {
        context.unregisterReceiver(mReceiver)
    }

    inner class InnerReceiver: BroadcastReceiver() {
        private val systemDialogReasonKey = "reason"
        private val systemDialogReasonHomeKey = "homekey"
        override fun onReceive(context: Context?, intent: Intent?) {
            val action = intent?.action
            if (action == Intent.ACTION_CLOSE_SYSTEM_DIALOGS) {
                val reason = intent.getStringExtra(systemDialogReasonKey)
                if (reason != null && reason == systemDialogReasonHomeKey) {
                    listener.onHomeButtonClick()
                }
            }
        }
    } 
}

T
Tomasz Kot

This works for me. You can override onUserLeaveHint method https://www.tutorialspoint.com/detect-home-button-press-in-android

@Override
    protected void onUserLeaveHint() {
        //
        super.onUserLeaveHint();
    }

This does work only when you have only one activity in your app. If you have multiple activity, this does not work bc when you switch to another activity, this method also triggered. Not good.
this also does not work if you trigger gallery intents and the like
this was also suggested as an answer to this question in 2017