如何为 UILabel 复制?

How do copy for UILabel?(如何为 UILabel 复制?)

问题描述

我有 IBOutlet UILabel *label;

我想这样做

UILabel *label = [titleLabel copy];
label.text = @"Clone";
titleLabel.text = @"Original";
NSLog(@"label : %@, title : %@",label.text,titleLabel.text);

这个抛出异常

* 由于未捕获的异常NSInvalidArgumentException"而终止应用程序，原因:-[UILabel copyWithZone:]: unrecognized selector sent to instance 0x6a4a450"* 首先抛出调用栈:(0x126f052 0x1823d0a 0x1270ced 0x11d5f00 0x11d5ce2 0x1271bd9 0x2ed6 0x1270e1a 0x2851 0x28264e 0x1e2a73 0x1e2ce2 0x1e2ea8 0x1e9d9a 0x24af 0x1ba9d6 0x1bb8a6 0x1ca743 0x1cb1f8 0x1beaa9 0x215cfa9 0x12431c5 0x11a8022 0x11a690a 0x11a5db4 0x11a5ccb 0x1bb2a7 0x1bca9b 0x21c2 0x2135)

* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UILabel copyWithZone:]: unrecognized selector sent to instance 0x6a4a450' * First throw call stack: (0x126f052 0x1823d0a 0x1270ced 0x11d5f00 0x11d5ce2 0x1271bd9 0x2ed6 0x1270e1a 0x2851 0x28264e 0x1e2a73 0x1e2ce2 0x1e2ea8 0x1e9d9a 0x24af 0x1ba9d6 0x1bb8a6 0x1ca743 0x1cb1f8 0x1beaa9 0x215cfa9 0x12431c5 0x11a8022 0x11a690a 0x11a5db4 0x11a5ccb 0x1bb2a7 0x1bca9b 0x21c2 0x2135)

推荐答案

没有公共的 Apple API 可以深度复制 UILabel.最好的办法是创建一个辅助方法来复制您关心的所有部分.

There is no public Apple API to deep copy a UILabel. Your best bet is to make a helper method which copies all the parts you care about.

- (UILabel *)deepLabelCopy:(UILabel *)label {
    UILabel *duplicateLabel = [[UILabel alloc] initWithFrame:label.frame];
    duplicateLabel.text = label.text;
    duplicateLabel.textColor = label.textColor;
    // etc... anything else which is important to your ULabel

    return [duplicateLabel autorelease];
}

如果您想在整个代码库中使用它，您可以将其更改为静态方法并将其放入某种实用程序类中.如果您将类命名为 LabelUtils，您可以执行类似...

If you want to use it all over your code base you can change it to a static method and put it in some sort of utility class. If you named the class LabelUtils you could do something like...

+ (UILabel *)deepLabelCopy(UILabel *)label {
    // ...
}

并且将使用 UILabel *dupLabel = [LabelUtils deepLabelCopy:origLabel];

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