片段和backStack显示/隐藏

Question

First of all thankyou for looking at this. I have 4 Fragments. One is a Menu Fragment that displays the menu. I have 2 List Fragments that display a list of data and pictures. the 4th fragment is a details fragment. Everything starts out normal.

Setup:

I click a list button it shows up and the menu frag is hidden behind it.

I click on an entry in the list fragment it uses an interface to pass data and show the details fragment.

I click the back button once it takes me to the list fragment like it should.

I click the back button again and it shows the menu frag like it should.

Problem:

If i click on a list button again the list shows up but the menu fragment is still showing behind it.

I am assuming that it has something to do with the backstack and maybe i am not using it correctly. Any help is greatly appreciated. If someone could explain this issue that would be amazing. If you would like me to post any part of my conde just let me know but i feel like my issue is with the backstack and this is the part of my code that i mess with the backstack.

private Fragment visible;
private Fragment mVisibleCached;
@Override
public void onBackPressed() {
    super.onBackPressed();
    visible = mVisibleCached;

}

. .

public void showFragment(int fragIn) {
    final FragmentManager fm = getSupportFragmentManager();
    final FragmentTransaction ft = fm.beginTransaction();
    ft.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);
    if (visible != null) {
        ft.hide(visible);
        //ft.remove(visible);
        mVisibleCached = visible;
        ft.addToBackStack(null);

    }
    switch (fragIn) {
    case 0:
        menuFrag = ((MenuFragment) fm.findFragmentByTag(MenuFragment.TAG));
        if (menuFrag == null) {
            menuFrag = MenuFragment.newInstance();
            ft.add(R.id.fragment_container, menuFrag, MenuFragment.TAG);
        } else {
            // ft.show(menuFrag);
            //ft.add(R.id.fragment_container, menuFrag, MenuFragment.TAG);
            if (!menuFrag.isVisible()) {
                ft.show(menuFrag);
            }
        }

        ft.addToBackStack(null);
        visible = menuFrag;
        break;
    case 1:
        programsFrag = ((ListFrag) fm.findFragmentByTag(PROGRAMS_TAG));
        if (programsFrag == null) {
            programsFrag = ListFrag.newInstance(false);
            ft.add(R.id.fragment_container, programsFrag, PROGRAMS_TAG);
        } else {
            // ft.show(programsFrag);
            //ft.add(R.id.fragment_container, programsFrag, PROGRAMS_TAG);

            // ft.replace(R.id.fragment_container, programsFrag);
            if (!programsFrag.isVisible()) {
                ft.show(programsFrag);
            }
        }
        ft.addToBackStack(null);
        visible = programsFrag;
        break;
    case 2:
        hostsFrag = ((ListFrag) fm.findFragmentByTag(HOSTS_TAG));
        if (hostsFrag == null) {
            hostsFrag = ListFrag.newInstance(true);
            ft.add(R.id.fragment_container, hostsFrag, HOSTS_TAG);
        } else {
            // ft.show(hostsFrag);
            //ft.add(R.id.fragment_container, hostsFrag, HOSTS_TAG);

            // ft.replace(R.id.fragment_container, hostsFrag);
            if (!hostsFrag.isVisible()) {
                ft.show(hostsFrag);
            }
        }
        ft.addToBackStack(null);
        visible = hostsFrag;
        break;
    case 3:
        detailsFrag = ((DetailsFrag) fm.findFragmentByTag(DetailsFrag.TAG));
        if (detailsFrag == null) {
            detailsFrag = DetailsFrag.newInstance();
            ft.add(R.id.fragment_container, detailsFrag, DetailsFrag.TAG);
        } else {
            //ft.add(R.id.fragment_container, detailsFrag, DetailsFrag.TAG);
            if (!detailsFrag.isVisible()) {
                ft.show(detailsFrag);
            }
        }
        ft.addToBackStack(null);
        visible = detailsFrag;
        break;
    }
    ft.commit();
}

Answer 1

I solved the issue by following your method, it is not elegant but it works for me..

Instead of your 2 fragments I used an integer var and an arraylist of integer (the integer are ids of fragments)

int visible;

ArrayList<Integer> cachedVisible= new ArrayList<Integer>();

Then in the method showing the right fragment i did something like this

private void setVisibleFragment(int id) {
if(visible!=0){
        cachedVisible.add(visible);
    }else{
        cachedVisible.add(R.id.home);
    }


   switch (id) {
        case R.id.settings:
        visible=R.id.settings;
        break;
    case R.id.services:
        ft.hide(fm.findFragmentById(R.id.settings_frag));
        ft.hide(fm.findFragmentById(R.id.plugin_frag));
        ft.show(fm.findFragmentById(R.id.service_frag));
        ft.addToBackStack(null);
        ft.commitAllowingStateLoss();
        visible=R.id.services;
        break;
        ....
   }
}

And at the end in the FragmentActivity

public void onBackPressed() {
    if(cachedVisible.size()==0){
        finish();
    }else{
    visible = cachedVisible.get(cachedVisible.size()-1);
    cachedVisible.remove(cachedVisible.size()-1);
     }
    setVisibleFragment(visible);
    cachedVisible.remove(cachedVisible.size()-1);   
}

Hope it can help someone ;)