ToggleDrawable 
ToggleDrawable helps to create animated drawable transitions using a minimalistic and clean API. The implementation relies on bezier curves instead of SVG graphics, and is compatible below API 19.
How?
The library provides a few implementations like SearchArrowDrawable, SearchCrossDrawable or DrawerArrowDrawable:
ToggleDrawable drawable = new SearchArrowDrawable(context);
mImageView.setImageDrawable(drawable);
drawable.setProgress(...); // animate
You can easily create your own transitions by passing several Bezier curves to ToggleDrawable:
ToggleDrawable drawable = new ToggleDrawable(context);
drawable.add(<start>, <end>);
drawable.add(<start>, <end>);
Or by simpy subclassing ToggleDrawable instead:
public class MyCustomToggleDrawable extends ToggleDrawable {
public MyCustomToggleDrawable(Context context) {
super(context, 0, R.style.CustomToggleDrawableStyle);
float radius = Math.round(getIntrinsicWidth()*0.5f);
// From circle to square
add(Bezier.quadrant(radius, 0), Bezier.line(radius, radius, radius, -radius));
add(Bezier.quadrant(radius, 90), Bezier.line(-radius, radius, radius, radius));
add(Bezier.quadrant(radius, 180), Bezier.line(-radius, radius, -radius, -radius));
add(Bezier.quadrant(radius, 270), Bezier.line(-radius, -radius, radius, -radius));
}
}
Look at the sample.
Install
This repositery can be found on JitPack:
https://jitpack.io/#renaudcerrato/ToggleDrawable
Add it in your root build.gradle at the end of repositories:
allprojects {
repositories {
...
maven { url "https://jitpack.io" }
}
}
Add the dependency:
dependencies {
compile 'com.github.renaudcerrato:ToggleDrawable:1.0.2'
}