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detect home button press in android


detect home button press in android  using -'android,android-homebutton'

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: http://nisha113a5.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
    

asked Sep 15, 2015 by GreO53
0 votes
27 views



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13 Answers

0 votes

Have you gone through this?: detect [home] button press

I am not the author , but came across it recently

hope it helps you !

****EDIT**** This no longer works as of 4.0. The last comment on this post: groups.google.com/forum/#!topic/android-developers/trRI99-HszQ

answered Sep 15, 2015 by JuanQuallsfv
0 votes

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.

answered Sep 15, 2015 by GinLedet
0 votes

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 InnerRecevier mRecevier;

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

    public void setOnHomePressedListener(OnHomePressedListener listener) {
        mListener = listener;
        mRecevier = new InnerRecevier();
    }

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

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

    class InnerRecevier 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 {
    public void onHomePressed();

    public void onHomeLongPressed();
}
answered Sep 15, 2015 by XYHRoryxjwto
0 votes

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 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:


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

answered Sep 15, 2015 by LorriBassyhb
0 votes

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..
  }
}
answered Sep 15, 2015 by MonGlaspie
0 votes

This is an old one but it might help someone.

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

This works for me.. :)

answered Sep 15, 2015 by ShoClemmons
0 votes

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.

answered Sep 15, 2015 by ClaudioStand
0 votes

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

answered Sep 15, 2015 by Ron04M
0 votes

The average app can get along fine without needing to know the difference between a Home press and a pause event. In other words, onPause() is usually sufficient.

Why do you want to do this? Giving us more information about your intentions could lead to a better overall strategy for you.

answered Sep 15, 2015 by XQNHannelor
0 votes

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.

answered Sep 15, 2015 by DarioTisdall
0 votes

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.

answered Sep 15, 2015 by EmersonCaran
0 votes

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 ;)

answered Sep 15, 2015 by GlennaBittne
0 votes

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.

answered Sep 15, 2015 by Oni42Y

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