iOS UIView动画效果 学习笔记

CGRect frame = _confirmV.frame;
    [UIView beginAnimations:nil context:nil];//动画定义开始
    [UIView setAnimationDuration:0.5];//动画的时长
    [UIView setAnimationDelay:0];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(removeConfirmView)];//动画完成时执行的SEL，必须设置delegate

    frame.origin.y += HEIGHT(self.view);//这三句就是要执行的动画语句
    targetView.frame = frame;
    targetView.alpha -= 0.1;

    [UIView commitAnimations];//动画定义结尾