如何创建一个多级UIImageView动画？ [英] How to create a multistage UIImageView animation?

问题描述

我试图做一个多级动画，以便UIImageView（1）淡入，（2）移动，（3）滑出屏幕。

I'm trying to do a multistage animation, so that a UIImageView (1) fades in, (2) moves, (3) slide off the screen.

只有第1阶段似乎工作。我做错了什么？代码如下：

Only stage 1 seems to work. What am I doing wrong? Here's the code:

// 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];
}

推荐答案

将自己设置为动画委托：

You need to add a call to set yourself as the animation delegate:

[UIView setAnimationDelegate:self];

在最后一个动画中将自己设置为委托（设置为nil）块。

It would be a good idea to unset yourself as the delegate (set to nil) in the last animation block.

这篇关于如何创建一个多级UIImageView动画？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！