Develop Reference

Nested fragment and back stack

I have a fragment in which there is a nested fragment which I add in this way:
if (home == null) {
home = new MyFragment();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
transaction.addToBackStack(MyFragment.class.getName());
transaction.add(R.id.child_fragment, home).commit();
}
When I enter another fragment and go back the child fragment from above is not there. I checked and the instance is different from null.
UPDATE: I changed the code as suggested by Ashwin S Ashok but it's still not working.

Try using these methods:
// Use this if you don't want to retain the fragment.
protected void replaceFragmentStack(int container, Fragment fragment) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(container, fragment);
fragmentTransaction.commit();
}
// Use this if you want to add the fragments in a stack.
protected void addFragmentStack(int container, Fragment fragment, String tag) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
fragmentTransaction.add(container, fragment, tag);
fragmentTransaction.addToBackStack(tag);
fragmentTransaction.commit();
}

I would suggest you to use getChildFragmentManager() when making transactions inside a fragment. And its a bug i guess.
You can check out this thread it will help you alot Android 4.2: back stack behaviour with nested fragments
Also you need to go through The Curious Techizen's blog
Here is the link for the github project sample for same mechanism
I hope this will help you.

Open a fragment, not in the current list of tabs, in a fragment

I want to open a fragment, which does not lie in the list of tabs, from a fragment in an onClick() function.
I have been struggling with this for a while now. Can someone give some pointers?
All the solutions that I have seen transition from one fragment to another(both being part of the tab list).
Thanks.

Create a instance of the fragment and use fragment Manager
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
LinkListFragment llf = new LinkListFragment();
ft.replace(R.id.container, llf);
ft.commit();

List view reload when back pressed in fragment

I have Fragment XYZFragment where i display the list view.On the Listview item click i replace the Fragment like this.
Fragment fragment=new XYZFragment();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction ft= fragmentManager.beginTransaction();
ft.addToBackStack(null);
ft.replace(R.id.content_frame, fragment).commit();
But my problem is when i click back button the fragment reload the listview.It is never happen when i used to use Activity.
So my question is how to save the instance of previous fragment so that it will prevent the reloading of Data.

without seeing your code we can't help you out but from your question i can figure out the problem, this solution may help you out.
create stack such that
private static Stack<Fragment> myFragStack;
myFragStack = new Stack<Fragment>();
//To Load the fragment
public void loadFragment(Fragment fragment){
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
myFragStack.lastElement().onPause();
ft.hide(myFragStack.lastElement());
myFragStack.push(fragment);
}
//onBackPressed
public void onBackPressed() {
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
if (myFragStack.size() > 1) {
ft.remove(myFragStack.pop());
myFragStack.lastElement().onResume();
ft.show(myFragStack.lastElement());
ft.commit();
}
}
It's a sample code.. you can change it as per your requirement.
ft.replace() will completely remove the view & will lose the context so you can't maintain your list state, but using stacks maintaining fragments with hide-show will solve your problem.

FragmentManager replace vs Add

In my application there is a FrameLayout on which I am adding various fragments
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragment_content, fragment, fargmentTag);
ft.commit();
Now it seems when I use the ft.replace(R.id.fragment_content, fragment, fargmentTag); and then in other places call
getSupportFragmentManager().findFragmentByTag(fargmentTag);
I always get null.
However if I use add instead of replace this problem is fixed but another problem appears that each fragment is added ontop of the other fragment and i can see the other fragments below.
I would prefer to use replace, but I need the saved fragment state. Also to be noted I am not using addToBackStack.

Try this and it would work.
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragment_content, fragment, fragmentTag);
ft.commitAllowingStateLoss();

You just basically answered your own question. Use addToBackStack().

FragmentManager: fm = getSupportFragmentManager(); fm.executePendingxxxx，try it.

How to show second fragment from first fragment with in a single activity

I am developing a simple android app only for tablets and using android 4.0. My application have the main screen like as follow:
Oncreate() of Main Activity I am adding Fragment A in the main.xml using following code:
FragmentTransaction ft = getFragmentManager().beginTransaction();
Fragment imageFragment = new ImageFragment();
ft.replace(R.id.fragment_container, imageFragment);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.addToBackStack(null);
ft.commit();
This fragment A just have only a Image view which is clickable. Now I want that when user click on Image view then another fragment (Fragment B) should call and it replace the image view. The Fragment B have a VideoView which play the video.
So My second screen should be like as follow:
My problem is I am not gettting "How to call second fragment from the first one with in main screen activity?"
I can use different activities but I do not want to do so and just want to run this using fragments.
Please guide me.

This is the simplest way:
1) Inside YourActivitycreate a method:
public void goToSecondFragment(){}
FragmentTransaction ft = getFragmentManager().beginTransaction();
Fragment secondFragment = new SecondFragment();
ft.replace(R.id.fragment_container, secondFragment);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.addToBackStack(null);
ft.commit();
}
2) In your first fragment, when you want to replace it, call:
YourActivity activity = (YourActivity) getActivity();
activity.goToSecondFragment();

You can do the same using below:
Adding a fragment with maintaining a back stack
FragmentManager supportFragmentManager = getSupportFragmentManager();
supportFragmentManager.addOnBackStackChangedListener(new OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
}
});
FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
fragmentTransaction.addToBackStack("fragmentTag");
fragmentTransaction.replace(R.id.slate, fragment, "fragmentTag");
fragmentTransaction.commit();
And Replacing a fragment
FragmentManager supportFragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
fragmentTransaction.replace(R.id.slate, fragment, "fragmentTag");
fragmentTransaction.commit();
Should work for you.