我正在尝试进行多级动画,以便UIImageView(1)淡入,(2)移动,(3)滑离屏幕。
只有第1阶段似乎有效。我究竟做错了什么?这是代码:
// FIRST PART - FADE IN
-(void)firstAnim
{
// 'sprite' is a UIImageView
[sprite setAlpha:0.1f];
[UIView beginAnimations:@"anim1" context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.25];
[UIView setAnimationDidStopSelector:@selector(secondAnim)];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[sprite setAlpha:1.0f];
[UIView commitAnimations];
}
// SECOND PART - MOVE
-(void)secondAnim
{
[UIView beginAnimations:@"anim2" context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.5];
[UIView setAnimationDidStopSelector:@selector(thirdAnim)];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
sprite.frame = CGRectMake(170, 184, 20, 20);
[UIView commitAnimations];
}
// THIRD PART - SLIDE OFF SCREEN
-(void)thirdAnim
{
[UIView beginAnimations:@"anim3" context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.5];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
sprite.frame = CGRectMake(170, 420, 20, 20);
[UIView commitAnimations];
}
答案 0 :(得分:4)
您需要添加一个调用以将自己设置为动画委托:
[UIView setAnimationDelegate:self];
在最后一个动画块中将自己设置为委托(设置为nil)是个好主意。
答案 1 :(得分:4)
您问题的完整解决方案是:
1)设置动画委托
2)使用正确的选择器和方法签名
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:.5];
[UIView setAnimationDelegate:self]; //set delegate!
[UIView setAnimationDidStopSelector:
@selector(secondAnim:finished:context:)];
-(void)secondAnim:(NSString *)animationID
finished:(NSNumber *)finished
context:(void *)context {
//animation #2
}