iphone - 核心动画警告 : "uncommitted CATransaction"

Question

我仅在设备上收到以下警告:

CoreAnimation: warning, deleted thread with uncommitted CATransaction; created by:
0   QuartzCore                          0x3763c65d <redacted> + 220
1   QuartzCore                          0x3763c541 <redacted> + 224
2   QuartzCore                          0x3763fe2f <redacted> + 30
3   QuartzCore                          0x3763b9bf <redacted> + 318
4   QuartzCore                          0x3763b87b <redacted> + 50
5   QuartzCore                          0x3763b80b <redacted> + 538
6   MyApp                              0x000df597 -[CommonClass orangeGradient:] + 382
7   MyApp                              0x000f70e1 -[HomeViewController updateStatusBar] + 1700
8   MyApp                              0x000f61bd -[HomeViewController statusRecieved] + 224
9   MyApp                              0x000cd323 -[CommonClass statusReceivedFromServer] + 142
10  MyApp                              0x000d833d -[CommonClass accountStatus] + 7416
11  Foundation                          0x35a3767d <redacted> + 972
12  libsystem_c.dylib                   0x35c9a311 <redacted> + 308
13  libsystem_c.dylib                   0x35c9a1d8 thread_start + 8

我在栈顶的方法如下:

- (void)orangeGradient: (UILabel *)fillLabel {
@synchronized([CommonClass class]) {
CAGradientLayer * gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = fillLabel.bounds;
gradientLayer.colors = [NSArray arrayWithObjects:(id)[UIColorFromRGB(0xfbb250) CGColor],(id)[UIColorFromRGB(0xf47c2a) CGColor], nil];
[fillLabel.layer addSublayer:gradientLayer];
}
}

知道为什么会出现这种情况，我该如何解决？

Answer 1

看起来 orangeGradient: 是从后台线程调用的。 Core Animation 将所有更改分组到 CATransactions 中。通常这是从运行循环自动完成的。在后台线程上(通常)没有运行循环，因此您必须自己创建事务:

- (void)orangeGradient: (UILabel *)fillLabel {
    @synchronized([CommonClass class]) {
        [CATransaction begin];
        CAGradientLayer * gradientLayer = [CAGradientLayer layer];
        gradientLayer.frame = fillLabel.bounds;
        gradientLayer.colors = [NSArray arrayWithObjects:(id)[UIColorFromRGB(0xfbb250) CGColor],(id)[UIColorFromRGB(0xf47c2a) CGColor], nil];
        [fillLabel.layer addSublayer:gradientLayer];
        [CATransaction commit];
    }
}

还有一个问题:UIKit 不是线程安全的。您不能在后台线程的 UILabel 上调用 bounds。