Question

I push a fragment on the fragment stack using the following code:

FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_right,
     R.anim.slide_in_left, R.anim.slide_out_left);
fragmentTransaction.replace(getId(), newFragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();

This way, when the fragment stack is popped, e.g. by pressing the back button, a fragment pop animation is played. However, there are situations in which i would like to pop the fragment backstack without showing this animation, e.g. because I just returned from another activity and want to display the previous fragment at once, without animation.

An example navigation could look like this:

• The user is on the start screen with the root fragment
• He selects an item on the root fragment which then displays a new fragment to show details of that item. It does so using a fragment transaction that sets animations both for the push and the pop case (so when the user presses the back button, the transition is animated)
• From this fragment he starts an activity which (for whatever reason) deletes the item that was just shown
• When this activity finishes, I would like to return to the root fragment without showing the “pop animation” of the “detail fragment”

Is there a way to pop the fragment backstack without playing the specified pop animation?

Answer 1

So Warpzit was on the right track, he just didn’t address your specific issue too well. I came across the exact same issue and here is how I solved it.

First I created a static boolean variable (for simplicity’s sake, lets put it in the FragmentUtils class)…

public class FragmentUtils {
    public static boolean sDisableFragmentAnimations = false;
}

Then, in EVERY fragment you have, you need to override the onCreateAnimation method…

@Override
public Animation onCreateAnimation(int transit, boolean enter, int nextAnim) {
    if (FragmentUtils.sDisableFragmentAnimations) {
        Animation a = new Animation() {};
        a.setDuration(0);
        return a;
    }
    return super.onCreateAnimation(transit, enter, nextAnim);
}

Then, when you need to clear the backstack from your activity simply do the following…

public void clearBackStack() {
    FragmentUtils.sDisableFragmentAnimations = true;
    getSupportFragmentManager().popBackStackImmediate(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
    FragmentUtils.sDisableFragmentAnimations = false;
}

And voila, a call to clearBackStack() will drop you back into the root fragment without any transition animations.

Hopefully the big G will add a less stupid way of doing this in the future.