Objective-C：仅限数字文本字段？ [英] Objective-C: Numbers only text field?

问题描述

可能重复：

Iphone UITextField只有整数

我想放置一个文本字段只接受数字（0-9，甚至不需要小数），但即使使用数字键盘输入选项，我仍然会得到一个带有各种符号的键盘。是否有更好的控制，是否有更好的控制我正在做什么，或者我只需要手动验证输入？

I want to place a text field that only accepts numbers (0-9, doesn't even need decimals), but even using the "Number Pad" entry option I still get a keyboard with various symbols on it. Is there a better control for this, is there a better control for what I'm doing, or do I just have to validate input manually?

推荐答案

以下代码将允许您仅输入数字以及限制可以使用的字符数。

The following code will allow you to only input numbers as well as limit the amount of characters that can be used.

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
{
    /*  limit to only numeric characters  */
    NSCharacterSet *myCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];
    for (int i = 0; i < [string length]; i++) {
        unichar c = [string characterAtIndex:i];
        if ([myCharSet characterIsMember:c]) {
            return YES;
        }
    }

    /*  limit the users input to only 9 characters  */
    NSUInteger newLength = [customTextField.text length] + [string length] - range.length;
    return (newLength > 9) ? NO : YES;
}

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