CODEWITHSUNDEEP
androidandroid-animationandroid-transitions
ZakTaccardi
ZakTaccardi

Reputation: 12467

How can you do a circular expanding hide on a view? (the opposite of a circular reveal)

I want to hide a View, starting at a x,y coordinate and expand this hide animation outward. Is this possible?

Essentially, this is the opposite of a circular reveal. I'm fine with this being a minSdk 21.

enter image description here

extra details

I have ActivityB (with a transluscent background) on top of ActivityA. AcitivityA has already been created, but it's not yet visible to the user. When you click the done button in the bottom right corner, I want to reveal ActivityA by hiding ActivityB (using the expanding circular hide animation, which starts where the user pressed the done button.)

Upvotes: 1

Views: 2306

Answers (1)

Rami Jemli
Rami Jemli

Reputation: 2641

You're thinking about this the opposite way. You say you want to hide Activity B but at the same time you're showing Activity A.
It's like looking at a half empty glass. It's half full and half empty. Both are true.

Try this :
Show Activity B. When you click done, show Activity A (with a transparent background) and start the reveal animation.

However, if you insist on the hiding part, here's how to do it.

View myView = findView(R.id.awesome_card);

// get the center for the clipping circle
int cx = (myView.getLeft() + myView.getRight()) / 2;
int cy = (myView.getTop() + myView.getBottom()) / 2;

// get the final radius for the clipping circle
int dx = Math.max(cx, myView.getWidth() - cx);
int dy = Math.max(cy, myView.getHeight() - cy);
float finalRadius = (float) Math.hypot(dx, dy);

SupportAnimator animator =
        ViewAnimationUtils.createCircularReveal(myView, cx, cy, finalRadius, 0);
animator.setInterpolator(new AccelerateDecelerateInterpolator());
animator.setDuration(1500);
animator.start();

Instead of starting from 0, start from finalRadius.
I recommend using a transparent background for all activities to avoid OVERDRAW for performance purposes.
For other users who are trying to achieve the Circular Reveal on Pre-Lollipop devices, this is the right library(CircularReveal) to do it. On pre-lollipop, it uses its own implementation. On lollipop and above, it uses the native implementation.

Upvotes: 3

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