如何检查片段是否在Activity OnBackpressed中可见

Question

How to check fragment is visible in Activity OnBackpressed

I want to check when user click back button in Searchfragment I want to set OnBackpressed is running ,but if user click back button in OtherFragment I want to set OnBackpressed is not running.

and I try this in Activity is not work

 btn_back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SearchFragment searchFragment = new SearchFragment();
                if (searchFragment.isVisible()){
                    onBackPressed();
                }

            }
        });

thanks for your help!

Answer 1

First of all, when you declare something like this:

SearchFragment searchFragment = new SearchFragment();

And then call

searchFragment.isVisible()

This will obviously return false since you didnt even add it to the container. What you need to do is to retrieve the fragment instance that you already added and check it's state.

I have once tried to use the method isVisible() but it is not entirely accurate, at least not for my case. What I came up with is to check the top fragment in the container as follow:

Fragment fragment = getActivity().getSupportFragmentManager().findFragmentById(R.id.fragment_container);
if(fragment instance of SearchFragment) //means your visible fragment is the SearchFragment
    onBackPressed();