UIView 弹簧API

UIView 的反弹动画API

//usingSpringWithDamping的范围为0.0f到1.0f，数值越小「弹簧」的振动效果越明显。
//initialSpringVelocity则表示初始的速度，数值越大一开始移动越快。

[UIView animateWithDuration:2 delay:0 usingSpringWithDamping:0.8 initialSpringVelocity:3 options:UIViewAnimationOptionCurveEaseIn animations:^{
        CGFloat y = [UIScreen mainScreen].bounds.size.height - frame.size.height;
        self.sheetView.frame = CGRectMake(frame.origin.x, y, frame.size.width, frame.size.height);
    } completion:^(BOOL finished) {
        
    }];