故障设置的最大长度文本字段

问题描述：

我无法设置的最大长度为文本字段的内容。我把过程实施我的头文件中UITextFieldDelegate。然后，我定义（然后叫）这个方法：

I'm having trouble setting a maximum length for the content of a text field. The process I took was implementing the UITextFieldDelegate in my header file. I then defined (and then called) this method:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return (newLength > 5) ? NO : YES;
}

这是我用了这里的建议在网站上的方法。我也试过这样：

This was a method that I got by suggestion here on the site. I've also tried this:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSUInteger newLength = [zipCode.text length] + [string length] - range.length;
return (newLength > 5) ? NO : YES;
}

拉链code是的，我连接到文本字段的插座。每次我已经改变了code，我确信重新连接插座。我有一种感觉那就是我失去了一个非常简单的事情。道歉，如果这是一个有点令人费解，我有很多东西需要学习！谢谢你。

"zipCode" is the the outlet that I connected to the text field. Each time I've changed the code I've made sure to reconnect the outlet. I have a feeling it's a very simple thing that I'm missing. Apologies if this is a little convoluted, I have a lot to learn! Thanks.

答

试试这个：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    return (zipCode.text.length + string.length <= 5);
}

然后，在 viewDidLoad中方法：

- (void)viewDidLoad {
    zipCode.delegate = self;
    //.....
    [super viewDidLoad];
}

故障设置的最大长度文本字段

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