Manage onBackPressed in single activity android app

Question

I have a single activity app and I want to manage app exit by pressing twice back button. Now I don't know how and where to manage onBack. Would you please help on this?

you can override onbackpressed() method of activity. refer below link https://stackoverflow.com/questions/18337536/android-overriding-onbackpressed — Shree, May 18 '21 at 18:01

score 0 · Answer 1 · answered May 18 '21 at 18:06

0

Can do something like this

override fun onBackPressed() {

    if (i == 0){
        i++
        return
    }
    else {
        i = 0
        super.onBackPressed()
    }
}

answered May 18 '21 at 18:06

Sarah Khan

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11

score 0 · Answer 2 · answered May 18 '21 at 18:16

Add this to your Activity

 private var doublePressToExit = false
override fun onBackPressed() {
    if (doublePressToExit) {
        super.onBackPressed()
        return
    }
    this.doublePressToExit = true
    Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show()

    Handler().postDelayed(Runnable { doublePressToExit = false }, 2000)  // to reset doublePressToExit to false after 2 sec
}

Keshav · Answer 3 · 2022-10-28T10:07:13.563

Implement this code in onBackpressed() function of parent activity

  override fun onBackPressed() {
     this.supportFragmentManager
         .primaryNavigationFragment
        ?.findNavController()?.popBackStack()
}

primaryNavigationFragment provide the instance of the fragment currently displayed on the screen, and from there, we can pop back Stack

this.supportFragmentManager.popBackStack()

can also work but in that case it destroys the reference of nav direction actions so opening another fragment after closing one would result in a crash with error

Navigation component - cannot be found from the current destination

Manage onBackPressed in single activity android app

3 Answers3