Question

我正在尝试显示不断滚动的“电影积分”。 VC代码如下所示。问题是动画开始前有大约12秒的延迟。动画开始后，呼叫之间不会重复延迟。在模拟器和iPhone5上可以看到相同的行为。

更感兴趣的是：当VC弹出时，应用程序会因cpu使用而疯狂（100％+）...我的笔记本电脑将达到200°。

显然这是没有开火的初始动画。如果完成块被注释掉，则不会发生任何动画。所以12秒延迟实际上是动画的第一次运行没有做任何事情，然后第二次调用实际上会在屏幕上发生一些事情。

有人可以解释我的错误或指向适当的文档。

- (void)loopCredits
{
   CGRect startFrame = _creditsView.frame;
   CGRect endFrame = CGRectMake(0, -568, 320, 568);

   [UIView animateWithDuration:10.0
                         delay:0.0
                       options:UIViewAnimationOptionCurveLinear
                    animations:^{
                       self.creditsView.frame = endFrame;
                    }
                    completion:^(BOOL finished) {
                       self.creditsView.frame = startFrame;
                       [self performSelector:@selector(loopCredits) withObject:nil afterDelay:0.0];
                    }
    ];

}

-(void)viewWillAppear:(BOOL)animated
{
   [super viewWillAppear:animated];

   self.navigationController.navigationBarHidden = NO;
}

-(void)viewDidAppear:(BOOL)animated
{
   [super viewDidAppear:animated];
//   [self loopCredits];
}

- (void)viewDidLoad
{
   [super viewDidLoad];

   [self createInfoString];
   self.creditsView.attributedText = self.text;

   [self loopCredits];
}

- (void)createInfoString
{
   NSString* path       = [[NSBundle mainBundle] pathForResource:@"InfoPageText" ofType:@"plist"];
   NSURL*    pathURL    = [[NSURL alloc] initFileURLWithPath:path];

   NSArray* temp        = [NSArray arrayWithContentsOfURL:pathURL];
   NSUInteger strLength = [[temp objectAtIndex:0] length];

   self.text            = [[NSMutableAttributedString alloc] initWithString:[temp objectAtIndex:0]];

   UIFont* font       = [UIFont fontWithName:@"Chalkduster" size:18.0f];
   UIColor* textColor = [UIColor colorWithRed:250.0/255.0 green:255.0/255.0 blue:255.0/255.0 alpha:1];

   [_text addAttribute:NSFontAttributeName value:font range:NSMakeRange(0, strLength)];
   [_text addAttribute:NSForegroundColorAttributeName value:textColor range:NSMakeRange(0, strLength)];
}

uiview动画延迟开始

0 个答案: