在UITextField中用逗号分隔的数字不起作用 [英] Numbers separated by commas in UITextField not working

问题描述

我试图在每3个字符后添加一个小数。 （倒数计数如下：1,325,541而不是1325451。）

I'm trying to add a decimal after every 3 characters. (Counting backwards like this: 1,325,541 instead of 1325451.)

这是我尝试过的：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSNumberFormatter *numberFormat = [[NSNumberFormatter alloc] init];
    [numberFormat setGroupingSeparator:@","];
    [numberFormat setGroupingSize:3];
    [numberFormat setNumberStyle:NSNumberFormatterDecimalStyle];

    NSNumber *amount = [numberFormat numberFromString:textField.text];
    textField.text = [numberFormat stringFromNumber:amount];
    return YES;
}

每3个字符后不插入逗号。我该怎么办才能修复它？

It doesn't insert a comma after every 3 characters. What can I do to fix it?

推荐答案

嗯，这最终会比你想象的更微妙，但是这个是我提出的：

Well, this ends up being a little more nuanced than you might expect, but this is what I came up with:

在@ bgfriend0的评论中提到， textField：shouldChangeCharactersInRange：replacementString 在申请之前被调用对文本字段的编辑（由于其他原因，这很有用）。这意味着，如果您当前的字符串是 123 并且用户输入 4 ，则该方法将被传递给以下作为参数：

As @bgfriend0's comment mentions, textField:shouldChangeCharactersInRange:replacementString gets called before applying an edit to a text field (this is useful for other reasons). Meaning, that if your current string was 123 and a user goes to type in 4, the method would be passed the following as parameters:

• textField： textField，但请注意这一点 textField.text 是 123


• 范围： NSRange {2,0}


• 字符串： 4

• textField: the textField, but note at this point textField.text is 123
• range: NSRange{2, 0}
• string: 4

并且有一种方法可以让这个函数在该方法中起作用，但是有更好的方法（我认为）。

And there is a way to make this function work from within that method, but there's a better way (I think).

实例化textField后，添加目标以收听编辑事件：

After you instantiate your textField, add a target to listen for editing events:

[textField addTarget:self 
              action:@selector(formatNumberIfNeeded:)    
    forControlEvents:UIControlEventEditingChanged];

只要在 UITextField 。我们将执行的 SEL 将如下所示：

This will get called anytime an editing change happens in a UITextField. The SEL that we'll be performing will look like this:

- (void)formatNumberIfNeeded:(UITextField *)textField{
    // you'll need to strip the commas for the formatter to work properly
    NSString * currentTextWithoutCommas = [textField.text stringByReplacingOccurrencesOfString:@"," withString:@""];

    NSNumberFormatter * numberFormatter = [[NSNumberFormatter alloc] init];
    numberFormatter.numberStyle = NSNumberFormatterDecimalStyle;

    NSNumber * numberFromString = [numberFormatter numberFromString:currentTextWithoutCommas];
    NSString * formattedNumberString = [numberFormatter stringFromNumber:numberFromString];

    textField.text = formattedNumberString;
}

现在，如果您需要进行本地化，事情会变得更加棘手，但是如果需要的话。

Now, things get slightly more tricky if you need to localize, but cross that bridge if needed.

至于 textField：shouldChangeCharactersInRange：replacementString ，这是进行字符验证的更好的地方。因此，检查字母的基本验证可能如下所示：

As for textField:shouldChangeCharactersInRange:replacementString, that's a much better place to do character validation. So, a basic validation to check for letters could look like:

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{

    NSRange illegalCharacterEntered = [string rangeOfCharacterFromSet:[NSCharacterSet letterCharacterSet]];
    if ( illegalCharacterEntered.location != NSNotFound ) {
        return NO;
    }

    return YES;
}

因此，使用这两位代码，您将能够更新textfield字符串包含逗号每隔3个字符，并且用户将无法输入任何字母表中的任何字母（但他们仍然可以输入其他'非法'字符，因此请根据需要扩展该验证。）

So with those two bits of code, you'll be able to update the textfield string to include a comma every 3rd character, and users wont be able to enter any letters of the alphabet (but they can still input other 'illegal' characters, so extend that validation as needed).

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