在 android 中检测主页按钮按下

Question

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? ie 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

Answer 1

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();
}

Answer 2

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.. :)

Answer 3

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.

Answer 4

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.

Answer 5

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.

Answer 6

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");
}

Answer 7

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/

Answer 8

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..
  }
}

Answer 9

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 ;)

Answer 10

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.

Answer 11

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. =)

Answer 12

Android Home Key handled by the framework layer you can't able to handle this in the application layer level. Because the home button action is already defined in the below level. But If you are developing your custom ROM, then It might be possible. Google restricted the HOME BUTTON override functions because of security reasons.

Answer 13

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.

Answer 14

override onUserLeaveHint method can catch the home press event, but you need also consider user click events. following codes works for me.

private boolean isUserClickToLeave = false;
private Handler mHandler = new Handler();

 Runnable resetUserClickFlagRunnable = new Runnable() {
    @Override
    public void run() {
        isUserClickToLeave = false;
    }
};

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    if (ev.getAction() == MotionEvent.ACTION_CANCEL || ev.getAction() == MotionEvent.ACTION_UP) {
        isUserClickToLeave = true;
        mHandler.removeCallbacks(resetUserClickFlagRunnable);
        mHandler.postDelayed(resetUserClickFlagRunnable, 1000);
    }
    return super.dispatchTouchEvent(ev);
}

@Override
protected void onUserLeaveHint() {
    super.onUserLeaveHint();
    if (!isUserClickToLeave ) {
        //user press home button case.
       onHomePressed();
    }
    isUserClickToLeave = false;
}

private onHomePressed() {
    //do something here.
}

Answer 15

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()
                }
            }
        }
    } 
}

Answer 16

SOLVED: This works for BACK, HOME and TASK OVERVIEW

@Override
public void onBackPressed() {
}

@Override
public void onPause() {
    if (isApplicationSentToBackground(MainActivity.this)){
        // Do what you want to do on detecting Home Key being Pressed
        Toast.makeText(this, "You pressed the task button!", Toast.LENGTH_LONG).show();
    }
    super.onPause();
    ActivityManager activityManager = (ActivityManager) getApplicationContext()
            .getSystemService(Context.ACTIVITY_SERVICE);

    activityManager.moveTaskToFront(getTaskId(), 0);
}

@SuppressWarnings("deprecation")
public boolean isApplicationSentToBackground(final Context context) {
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(1);
    if (!tasks.isEmpty()) {
        ComponentName topActivity = tasks.get(0).topActivity;
        if (!topActivity.getPackageName().equals(context.getPackageName())) {
            return true;
        }
    }
    return false;
}

And add to manifest: android.permission.REORDER_TASKS

Answer 17

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

Answer 18

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.

Answer 19

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();
    }