Android long press system back button listener

Question

I want to add a listener for when the android system back button is long pressed i.e. a long press version of Activity.onBackPressed

This only needs to work when my app is visible.

Chrome shows the history menu when back is long pressed so it must be possible but can't find a hook for it. Thanks

check this answer https://stackoverflow.com/a/4930950/8596924 — Tobibur Rahman, Jul 06 '19 at 10:13

score 5 · Accepted Answer · answered Jul 06 '19 at 10:17

5

You can try overriding the onKeyLongPress method inside your Activity.

@Override
public boolean onKeyLongPress(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        System.out.println("Back button long pressed");
        return true;
    }
    return super.onKeyLongPress(keyCode, event);
}

answered Jul 06 '19 at 10:17

oemel09

744
7
15

Back buttons don't create key events. – Gabe Sechan Jul 06 '19 at 10:33
1

I tested it on a sample app and it did work perfectly fine though. – oemel09 Jul 06 '19 at 11:08
Before Android 10, onKeyLongPress can catch back event in pressing the back button. But after Android 10, onKeyLongPress can not catch back gesture from edge to edge – Fantasy Fang Jan 27 '21 at 02:47

score 1 · Answer 2 · answered Nov 27 '20 at 02:56

You can look at how firefox implement the Long Back Press.

https://github.com/mozilla-mobile/fenix/blob/master/app/src/main/java/org/mozilla/fenix/HomeActivity.kt

they implement it using both onKeyDown/onKeyUp and onKeyLongPress.

the reason both are used is because

Android N and Huawei devices have broken onKeyLongPress events for the back button, so we instead implement the long press behavior ourselves

For short presses, we cancel the callback in onKeyUp

For long presses, the normal keyPress is marked as cancelled, hence won't be handled elsewhere (but Android still provides the haptic feedback), and the long press action is run

Below is their implementation.

// See onKeyDown for why this is necessary
private var backLongPressJob: Job? = null

private fun shouldUseCustomBackLongPress(): Boolean {
    val isAndroidN =
        Build.VERSION.SDK_INT == Build.VERSION_CODES.N || Build.VERSION.SDK_INT == Build.VERSION_CODES.N_MR1
    // Huawei devices seem to have problems with onKeyLongPress
    // See https://github.com/mozilla-mobile/fenix/issues/13498
    val isHuawei = Build.MANUFACTURER.equals("huawei", ignoreCase = true)
    return isAndroidN || isHuawei
}

private fun handleBackLongPress(): Boolean {
    supportFragmentManager.primaryNavigationFragment?.childFragmentManager?.fragments?.forEach {
        if (it is OnBackLongPressedListener && it.onBackLongPressed()) {
            return true
        }
    }
    return false
}

final override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
    // Inspired by https://searchfox.org/mozilla-esr68/source/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java#584-613
    // Android N and Huawei devices have broken onKeyLongPress events for the back button, so we
    // instead implement the long press behavior ourselves
    // - For short presses, we cancel the callback in onKeyUp
    // - For long presses, the normal keypress is marked as cancelled, hence won't be handled elsewhere
    //   (but Android still provides the haptic feedback), and the long press action is run
    if (shouldUseCustomBackLongPress() && keyCode == KeyEvent.KEYCODE_BACK) {
        backLongPressJob = lifecycleScope.launch {
            delay(ViewConfiguration.getLongPressTimeout().toLong())
            handleBackLongPress()
        }
    }
    return super.onKeyDown(keyCode, event)
}

final override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
    if (shouldUseCustomBackLongPress() && keyCode == KeyEvent.KEYCODE_BACK) {
        backLongPressJob?.cancel()
    }
    return super.onKeyUp(keyCode, event)
}

final override fun onKeyLongPress(keyCode: Int, event: KeyEvent?): Boolean {
    // onKeyLongPress is broken in Android N so we don't handle back button long presses here
    // for N. The version check ensures we don't handle back button long presses twice.
    if (!shouldUseCustomBackLongPress() && keyCode == KeyEvent.KEYCODE_BACK) {
        return handleBackLongPress()
    }
    return super.onKeyLongPress(keyCode, event)
}

score 0 · Answer 3 · answered Aug 02 '19 at 14:03

I hope below idea works!!!

Add below code in your activity

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        //This event will be triggered after 1 second. 
        //In case if you move out of KEYCODE_BACK, onKeyUp event will be triggered and this event will be cancelled 
        handler.postDelayed(mLongPressed, 1000); 
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
    handler.removeCallbacks(mLongPressed);
    return super.onKeyUp(keyCode, event);
}

handler code:

final Handler handler = new Handler();
Runnable mLongPressed = new Runnable() {
    public void run() {
        Log.i("Activity", "Long press detected").
       //Add your code
    }
};

Android long press system back button listener

3 Answers3

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