Android: how to popBackStack Fragment if the application is background?

Question

I have an fragment monitoring some applications add/remove status, and when this happens, I need to replace to another frament, and remove the first one from the back stack (because I dont want to go back to it again).

But I fail to do so, when the application is background, the popBackStack always throws the exception:

06-06 14:44:39.264: E/AndroidRuntime(9428): Process: com.mmx.smarthome, PID: 9428
06-06 14:44:39.264: E/AndroidRuntime(9428): java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
06-06 14:44:39.264: E/AndroidRuntime(9428):     at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1354)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1372)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at android.support.v4.app.FragmentManagerImpl.popBackStack(FragmentManager.java:499)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at com.mmx.aircon.band.BandSportsFragment.gotoBandControlFragment(BandSportsFragment.java:160)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at com.mmx.aircon.band.BandSportsFragment.handleMessage(BandSportsFragment.java:220)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at com.mmx.aircon.common.NoLeakHandler$WeakRefHandler.handleMessage(NoLeakHandler.java:137)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at android.os.Handler.dispatchMessage(Handler.java:102)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at android.os.Looper.loop(Looper.java:136)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at android.app.ActivityThread.main(ActivityThread.java:5047)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at java.lang.reflect.Method.invokeNative(Native Method)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at java.lang.reflect.Method.invoke(Method.java:515)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
06-06 14:44:39.264: E/AndroidRuntime(9428):     at dalvik.system.NativeStart.main(Native Method)

the code is below:

private void gotoBandControlFragment() {
    Fragment bandControlFragment = new BandControlFragment(getActivity());
    FragmentManager fragmentManager = getFragmentManager();
    fragmentManager.popBackStack(null,
            FragmentManager.POP_BACK_STACK_INCLUSIVE);
    FragmentTransaction ft = fragmentManager.beginTransaction();

    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
    ft.replace(R.id.view_fragment, bandControlFragment, null);
    ft.commitAllowingStateLoss();
}

I override the onSaveInstanceState but not help

@Override
public void onSaveInstanceState(Bundle outState) {
}

How to popback it?

Does anybody have solution ? – Hiren Patel Jan 03 '20 at 06:47 — Hiren Patel, Jan 03 '20 at 06:47

score 0 · Answer 1 · answered May 16 '17 at 16:06

If the app is in background you could raise a boolean flag to remember that the method should be called when the app comes back to foreground. Use the Android activity lifecycle callbacks:

private boolean mIsVisible = false;

@Override
protected void onResume() {
    super.onResume();

    mIsVisible = true;

    if (mShouldGoToBandControlFragment) {
        gotoBandControlFragment();
    }
}

@Override
protected void onPause() {
    mIsVisible = false;
    super.onPause();
}

private void gotoBandControlFragment() {
    if (mIsVisible) {
        mShouldGoToBandControlFragment = false;
        Fragment bandControlFragment = new BandControlFragment(getActivity());
        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.popBackStack(null,
                FragmentManager.POP_BACK_STACK_INCLUSIVE);
        FragmentTransaction ft = fragmentManager.beginTransaction();

        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        ft.replace(R.id.view_fragment, bandControlFragment, null);
        ft.commitAllowingStateLoss();
    } else {
        mShouldGoToBandControlFragment = true;
    }
}

Android: how to popBackStack Fragment if the application is background?

1 Answers1