贝塞尔曲线动画简单使用

想做一个控件按照曲线轨迹运动的动画所以就用到了贝塞尔曲线

不废话直接上代码

public class BezierEvaluator implements TypeEvaluator<PointF> {

 @Override
public PointF evaluate(float fraction, PointF startValue, PointF endValue) {
final float t = fraction;
float T = 1.0f - t;
PointF point = new PointF();

 // PointF point0 = (PointF)startValue;起始坐标可以通过调用时传入
PointF point0 = new PointF();
PointF point1 = new PointF();
PointF point2 = new PointF();
PointF point3 = new PointF();

point0.set(-100, 305);
point1.set(-350, 280);//点一控制曲线弧度
point2.set(-400, 230);//点二控制曲线弧度
point3.set(160, 203);

 // PointF point3 = (PointF)endValue;结束坐标可以通过调用时传入
 //贝塞尔公式
point.x = T * T * T * (point0.x) + 3 * T * T * t * (point1.x) + 3 * T * t * t * (point2.x) + t * t * t * (point3.x);

point.y = T * T * T * (point0.y) + 3 * T * T * t * (point1.y) + 3 * T * t * t * (point2.y) + t * t * t * (point3.y);
return point;
 }

//调用上面的class例如在mainactivity中，可以用下面的方法
private void Curve(final FrameLayout layout, int timer) {
    ValueAnimator valueAnimator;
    valueAnimator = ValueAnimator.ofObject(new BezierEvaluator(), new PointF(0, 0), new PointF(100, 100));//传入初始坐标与结束坐标根据需求调整
    valueAnimator.setDuration(timer);//动画持续时间
    valueAnimator.addUpdateListener(new AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            PointF pointF = (PointF) animation.getAnimatedValue();
            layout.setX(pointF.x);
            layout.setY(pointF.y);
        }
    });
    //动画监听
    valueAnimator.addListener(new AnimatorListener() {

        @Override
        public void onAnimationStart(Animator animation) {
        }

        @Override
        public void onAnimationRepeat(Animator animation) {
        }

        @Override
        public void onAnimationEnd(Animator animation) {            
        }

        @Override
        public void onAnimationCancel(Animator animation) {
        }
    });
    //开始动画
    valueAnimator.start();
}

通过 Curve(layout（想要运动的控件）, 1000（运动时间）); 我们就可以使用了