如何限制UITextField中的小数点数？ [英] How can I limit the number of decimal points in a UITextField?

问题描述

我有一个UITextField，点击后会在左下角显示一个带小数点的数字键盘。我试图限制该字段，以便用户只能放置1个十进制标记

I have a UITextField that when clicked brings up a number pad with a decimal point in the bottom left. I am trying to limit the field so that a user can only place 1 decimal mark

例如

2.5 OK

2 ..5不行

e.g.
2.5 OK
2..5 NOT OK

推荐答案

实现这样的shouldChangeCharactersInRange方法：

Implement the shouldChangeCharactersInRange method like this:

// Only allow one decimal point
// Example assumes ARC - Implement proper memory management if not using.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
{
    NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
    NSArray  *arrayOfString = [newString componentsSeparatedByString:@"."];

    if ([arrayOfString count] > 2 ) 
        return NO;

    return YES;
}

这会创建一个由小数点分割的字符串数组，所以如果有的话一个以上的小数点，我们将在数组中至少有3个元素。

This creates an array of strings split by the decimal point, so if there is more than one decimal point we will have at least 3 elements in the array.

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