Question

我疯狂地不理解UIViewTransitionfromView的奇怪行为：第一个视图首先显示没有动画。这是代码：

UIImageView *backstar=[[UIImageView alloc]initWithFrame:CGRectMake(50, 50, 205, 205)];
    backstar.image=[UIImage imageNamed:@"backstar.png"];

UIImageView *star=[[UIImageView alloc]initWithFrame:CGRectMake(50, 50, 205, 205)];
star.image=[UIImage imageNamed:@"star.png"];

UIView *containerView=[[UIView alloc]initWithFrame:CGRectMake(50, 50, 205, 205)];
containerView.backgroundColor=[UIColor blackColor];
[self.view addSubview:containerView];
[containerView addSubview:backstar]; // if I don't do this nothing happens, container view stays f*** deep black
[containerView addSubview:star];

//if i remove the animation line, star is displayed of course, on top of backstar

[UIView transitionFromView:star toView:backstar  duration:2.0 options:UIViewAnimationOptionShowHideTransitionViews | UIViewAnimationOptionTransitionFlipFromLeft completion:^(BOOL finished){} ];

到底哪里是我的错？应该可以不删除imageViews，而是显示/隐藏它们，如Apple doc中所述！

非常感谢

Answer 1

从你的帖子中你不清楚你有这个代码。如果你在viewDiLoad或viewWillAppear中拥有它，我发现它不起作用。您需要获取第一个视图并且可见（在viewDidLoad或viewWillAppear中），然后添加第二个视图并在另一个方法中进行转换（可以使用按钮或performSelector调用：withObject：afterDelay :)。此外，如果您想从星号转到后星号，则应首先将星号添加到视图中，然后仅在您想要进行过渡时添加后星号。这对我有用：

@implementation TransitionTestViewController
@synthesize star,backstar;

-(void)viewDidLoad {
    self.backstar=[[UIImageView alloc]initWithFrame:CGRectMake(50, 50, 205, 205)];
    backstar.image=[UIImage imageNamed:@"backstar.png"];
    self.star=[[UIImageView alloc]initWithFrame:CGRectMake(50, 50, 205, 205)];
    star.image=[UIImage imageNamed:@"star.png"];
    [self.view addSubview:star];
    //[self performSelector:@selector(flipViews:) withObject:nil afterDelay:.01];
}

-(IBAction)flipViews:(UIButton *) sender {
    [self.view addSubview:backstar];
    [UIView transitionFromView:self.star toView:self.backstar  duration:2.0 options: UIViewAnimationOptionShowHideTransitionViews |UIViewAnimationOptionTransitionFlipFromLeft completion:^(BOOL finished){}];
}

UIViewTransitionfromView：永远不会工作，只显示第二个图像

1 个答案: