Implement onBackPressed() in Fragment

Question

So in my fragment I have a toolbar back button but I also have the phone's back button. When I tap on the toolbar one I need to just call the activity's onBackPressed and when I tap on phone's back button some specific functionality needs to happen. How do I override onBackPressed() method in the activity to handle both cases and use it in fragment as well?

You can achieve this by checking for the system hardware back button like described here: https://stackoverflow.com/questions/8094715/how-to-catch-event-with-hardware-back-button-on-android — Mark P., Dec 10 '19 at 15:47
Does this answer your question? [How to implement onBackPressed() in Fragments?](https://stackoverflow.com/questions/5448653/how-to-implement-onbackpressed-in-fragments) — Quinn, Dec 10 '19 at 16:07

score 0 · Answer 1 · answered Dec 10 '19 at 16:29

Do you have a way to track the fragments? Assuming you have the fragment tag set while loading it.

        int _contentContainerId;
        String sFragmentTag

        // Get the fragment manager
        FragmentManager fm = getSupportFragmentManager();

        // Change the container based on the parameters
        _contentContainerId = (nViewId == 0) ? R.id.container_application : nViewId;

        // Check if a fragment already exists. 
        Fragment currentFragment = fm.findFragmentById(_contentContainerId);

        // if it does not exist, then add the fragment, else replace it
        if (currentFragment == null) {
            fragTrans.add(_contentContainerId, fragmentObject, sFragmentTag);
        } else {
            fragTrans.replace(_contentContainerId, fragmentObject, sFragmentTag);
        }

In your Activity which is the container for the fragments

@Override
public void onBackPressed() {
    String currentFrag = getCurrentFragment(this, Constants.FRAG_CONTAINER_ID);

    if (currentFrag.equalsIgnoreCase()) {
        //your backpress logic for the fragment
    } else if (...) {

    } else {
        //normal backpress
        super.onBackPressed();
    }
}
}

public String getCurrentFragment(Context ctx, int containerId) {
    Fragment currentFrag;
    currentFrag = ((FragmentActivity) ctx).getSupportFragmentManager().findFragmentById(containerId);
    if (currentFrag != null) {
        String currentFragTag = currentFrag.getTag();
        if (StringUtils.isNotBlank(currentFragTag))
            return currentFragTag;
        else
            return "";
    } else {
        return "";
    }
}

Implement onBackPressed() in Fragment

1 Answers1