NativeScript/nativescript-core/ui/transition/fade-transition.android.ts

import { Transition, AndroidTransitionType } from ".";

export class FadeTransition extends Transition {
	public createAndroidAnimator(
		transitionType: string
	): android.animation.AnimatorSet {
		const animatorSet = new android.animation.AnimatorSet();
		const alphaValues = Array.create("float", 2);
		switch (transitionType) {
			case AndroidTransitionType.enter:
			case AndroidTransitionType.popEnter:
				alphaValues[0] = 0;
				alphaValues[1] = 1;
				break;
			case AndroidTransitionType.exit:
			case AndroidTransitionType.popExit:
				alphaValues[0] = 1;
				alphaValues[1] = 0;
				break;
		}

		const animator = <android.animation.Animator>(
			android.animation.ObjectAnimator.ofFloat(null, "alpha", alphaValues)
		);
		const duration = this.getDuration();
		if (duration !== undefined) {
			animator.setDuration(duration);
		}

		animator.setInterpolator(this.getCurve());
		animatorSet.play(animator);

		return animatorSet;
	}
}