为CATextLayer字符串属性设置动画

Question

我正在尝试动画CATextLayer的字符串属性，这样我就可以使用AV Foundation为我的视频添加时间戳。有没有人知道如何动画，这样我就可以每秒改变字符串值？

Answer 1

NSString *labelText = @"foobar";
[textLayer setString:labelText];

它必须在主线程上运行，所以我使用以下代码：

 NSString *labelText = @"foobar";
[textLayer performSelector:@selector(setString:) withObject:labelText waitUntilDone:YES];

如果您经常更新，则应禁用文本更改之间的动画：

NSString *labelText = @"foobar";    
[CATransaction begin];
[CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions];
[textLayer performSelector:@selector(setString:) withObject:labelText waitUntilDone:YES];
[CATransaction commit];