Android - Different transitions with multiple shared elements

Question

I'm working with Android Lollipop Transitions, and I've sumbled upon the following problem:

1. I have CardView with an ImageView and, on top of it, a TextView.
2. When I click on the card, a new Activity is launched, and it contains both the ImageView and the TextView in different positions.
3. If I don't include the TextView in the Transition as a shared element, it suddenly dissapears [goes behind] the ImageView, which doesn't look, well, great.
4. If I include it, it doesn't scale the text nicely and suddenly changes to the final size (I am aware of this solution already, but the problem is I want to keep also the default ImageView Transition, which is a combination of a ChangeBounds Transition, a ChangeImageTransform, ... among others).

So, anybody knows how to have different transitions being thrown for different shared views when launching the new Activity?

Cheers

Answer 1

The way you pointed to it in your answer can be applied for this purpose but it's actually for accepting only suitable View types by a special transition (such as only ImageViews for ChangeImageTransform).

You can use addTarget(Class targetType) instead:

final Transition transition = new TransitionSet()
    .addTransition(new ChangeTransform()).addTarget(TextView.class) // Only for TextViews
    .addTransition(new ChangeImageTransform()).addTarget(ImageView.class) // Only for ImageViews
    .addTransition(new ChangeBounds()); // For both

setSharedElementEnterTransition(transition);

This way is more simple and more logical. Also, it can be used for some other filterings (by transitionName and etc). See addTarget() overloaded types.

Answer 2

OK,

This is achievable extending the Transition class. Since I wanted to animate differently an ImageView and a TextView, I just wrote a TextTransform child class ofTransform, analogous to the ChangeImageTransform one which is part of the Android API 21+. The key was overriding this method (shown the case for ChangeImageTransform which looks for ImageView objects):

@Override
private void captureValues(TransitionValues transitionValues) {
    View view = transitionValues.view;
    if (!(view instanceof ImageView) || view.getVisibility() != View.VISIBLE) {
        return;
    }
    (...)
}

Then you apply all transforms to the new scene, and relevant transform will be attached to their corresponding views:

<transitionSet xmlns:android="http://schemas.android.com/apk/res/android">
    <fade android:fadingMode="fade_out" />
    <changeBounds />
    <changeImageTransform />
    <com.mypackage.transforms.TextTransform />
    <fade android:fadingMode="fade_in" />
</transitionSet>

And then you set this Transition on the OnCreate method of the new Activity using setSharedElementEnterTransition(inflatedTransitionSet);