Question

我会尝试创建一个伪动画，当一个视图出现时。这是我的代码：

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];

    _image1.hidden = NO;
    sleep(1);
    _label1.hidden = YES;
    sleep(1);
    _image2.hidden = NO;
    sleep(1);
    _label2.hidden = YES;
    sleep(1);
}

但是在每次sleep（）之前视图都没有更新。我必须添加什么，在显示或隐藏图像或标签后视图会更新？

Answer 1

试试这个：

[_image1 performSelector:@selector(setHidden:) withObject:[NSNumber numberWithBool:true] afterDelay:1];
[_label1 performSelector:@selector(setHidden:) withObject:[NSNumber numberWithBool:false] afterDelay:2];
[_image2 performSelector:@selector(setHidden:) withObject:[NSNumber numberWithBool:true] afterDelay:3];
[_label2 performSelector:@selector(setHidden:) withObject:[NSNumber numberWithBool:false] afterDelay:4];

Answer 2

您无法使用sleep，因为它会停止您当前的主题并阻止您的应用更新显示。

我建议使用......

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.5]; // you can also set this to 0.0
[UIView setAnimationDelay:1.0]; // the delay

// your changes which should be animated, example:
_image1.alpha = 0.0;

[UIView commitAnimations];

简单且可扩展。

如何在viewDidAppear中更新视图

2 个答案: