Double fragment instance when it comes from background-CodePudding

I've got the problem with creating multiple fragment instances in OnCreate. When i close the app using Home button and I will return to the app, the fragment instance is created one more time. How can I prevent this?

fragment = FragmentMain.newInstance(intent.extras?.getSerializable(DATA_MAIN)).also {
        supportFragmentManager.beginTransaction()
                .add(frameLayout.id, it, FragmentMain::class.java.simpleName)
                .addToBackStack(FragmentMain::class.java.simpleName)
                .commit()
               }

CodePudding user response：

This is expected behavior, as Android recreates the fragments after process death that are added to the fragment manager.

You're just also adding a 2nd new fragment on top of the one created by Android, which, you probably don't want to do.

fragment = when {
    savedInstanceState == null -> FragmentMain.newInstance(intent.extras?.getSerializable(DATA_MAIN)).also {
        supportFragmentManager.beginTransaction()
                .add(frameLayout.id, it, FragmentMain::class.java.simpleName)
                .addToBackStack(FragmentMain::class.java.simpleName)
                .commit()
               }
    else -> supportFragmentManager.findFragmentByTag(FragmentMain::class.java.simpleName)
}