呼吸效果的拦截器
public class BreatheInterpolator implements TimeInterpolator {
@Override
public float getInterpolation(float input) {
float x = 6 * input;
float k = 1.0f / 3;
int t = 6;
int n = 1;//控制函数周期，这里取此函数的第一个周期
float PI = 3.1416f;
float output = 0;
if (x >= ((n - 1) * t) && x < ((n - (1 - k)) * t)) {
output = (float) (0.5 * Math.sin((PI / (k * t)) * ((x - k * t / 2) - (n - 1) * t)) + 0.5);
} else if (x >= (n - (1 - k)) * t && x < n * t) {
output = (float) Math.pow((0.5 * Math.sin((PI / ((1 - k) * t)) * ((x - (3 - k) * t / 2) - (n - 1) * t)) + 0.5), 2);
}
return output;
}
}
private void startAlphaBreathAnimation() {
ObjectAnimator alphaAnimator = ObjectAnimator.ofFloat(tvShowBreathing, "alpha", 0f, 1f);
alphaAnimator.setDuration(4000);
alphaAnimator.setInterpolator(new BreatheInterpolator());//使用自定义的插值器
alphaAnimator.setRepeatCount(ValueAnimator.INFINITE);
alphaAnimator.start();
}
