对UIAnimation的理解

Question

我正在尝试使用下面的代码来执行一些动画

-(void) performSlidingfromX:(int) xx fromY:(int) yy 
{
UIImageView *Image= [self getImage];

[UIView beginAnimations:nil context:NULL];  
[UIView setAnimationDuration: 1.0];
[UIView setAnimationBeginsFromCurrentState:true];
[UIView setAnimationCurve: UIViewAnimationCurveEaseOut];
[token setFrame:CGRectMake(xx, yy, 64, 64)];
[UIView commitAnimations];

}

我就像在for循环中一样调用

for (i = 0; i < totMoves; i++) {
    Moment *m = [moments objectAtIndex:i];
    int xx= [m X];
    int yy= [m Y];

    [self performSlidingfromX:xx fromY:yy];

}

我面临的问题是，它会动画到最终位置，例如，如果我为xx，yy输入以下时刻

0,0
50,0
50,50

它将图像从0,0对角线移动到50,50，我希望它先水平滑动，然后垂直滑动。

有什么帮助吗？

谢谢

Answer 1

使用新的块动画。它简单且稳定：

[UIView animateWithDuration:0.5 
                          delay:0 
                        options:UIViewAnimationOptionBeginFromCurrentState
                     animations:^{
                         [token setFrame:CGRectMake(xx, 0, 64, 64)];
                         //here you may add any othe actions, but notice, that ALL of them will do in SINGLE step. so, we setting ONLY xx coordinate to move it horizantly first.
                     } 
                     completion:^(BOOL finished){

                         //here any actions, thet must be done AFTER 1st animation is finished. If you whant to loop animations, call your function here.
                         [UIView animateWithDuration:0.5 
                                               delay:0 
                                             options:UIViewAnimationOptionBeginFromCurrentState 
                                          animations:^{[token setFrame:CGRectMake(xx, yy, 64, 64)];} // adding yy coordinate to move it verticaly} 
                                          completion:nil];
                     }];

Answer 2

问题是你在for循环中不断调用"performSlidingfromX:xx fromY:yy“。尝试以下代码：

     i=0;
     Moment *m = [moments objectAtIndex:i];
     int xx= [m X];
     int yy= [m Y];
     [self performSlidingfromX:xx fromY:yy];

-(void) performSlidingfromX:(int) xx fromY:(int) yy 
{
i++;
[UIView beginAnimations:nil context:NULL];  
[UIView setAnimationDuration: 1.0];
[UIView setAnimationBeginsFromCurrentState:true];
[UIView setAnimationCurve: UIViewAnimationCurveEaseOut];
[token setFrame:CGRectMake(xx, yy, 64, 64)];
[UIView commitAnimations];


[self performSelector:@selector(call:) withObject:[NSNumber numberWithInt:i] afterDelay:1.1];

}
-(void)call
{
 Moment *m = [moments objectAtIndex:i];
     int xx= [m X];
     int yy= [m Y];
     [self performSlidingfromX:xx fromY:yy];
 }

Answer 3

制作动画不是阻塞调用。您的代码不会停止并等待动画完成。在开始动画之后，循环的下一次迭代将立即运行。这将创建一个新动画，该动画会影响相同的属性，因此它将替换以前的动画。你得到的结果就好像你只运行了循环的最后一次迭代。

不幸的是，没有简单的代码块来完成您想要做的事情。您需要检测动画何时结束，然后开始下一个动画。您需要在比局部变量范围更广的范围内跟踪您的状态(主要是您所在的状态)。