@Nullable
    public Transition getTransitionAt(int index) {
        if (index < 0 || index >= mTransitions.size()) {
            return null;
        }
        return mTransitions.get(index);
    }
@ Nullable public Transition getTransitionAt ( int index ) { if ( index < 0 || index >= mTransitions . size ( ) ) { return null ; } return mTransitions . get ( index ) ; }
Returns the child Transition at the specified position in the TransitionSet.

@param index The position of the Transition to retrieve.
@see #addTransition(Transition)
@see #getTransitionCount()