检查UITextField的输入是否仅为数字 [英] Check that a input to UITextField is numeric only

问题描述

如何验证 UITextField 的字符串输入？

How do I validate the string input to a UITextField? I want to check that the string is numeric, including decimal points.

推荐答案

我在Mac应用程式中使用这个程式码，或类似应该与iPhone一起工作。它是基于RegexKitLite正则表达式，并且当其无效时将文本变为红色。

I use this code in my Mac app, the same or similar should work with the iPhone. It's based on the RegexKitLite regular expressions and turns the text red when its invalid.

static bool TextIsValidValue( NSString* newText, double &value )
{
    bool result = false;

    if ( [newText isMatchedByRegex:@"^(?:|0|[1-9]\\d*)(?:\\.\\d*)?$"] ) {
        result = true;
        value = [newText doubleValue];
    }
    return result;
}

- (IBAction) doTextChanged:(id)sender;
{
    double value;
    if ( TextIsValidValue( [i_pause stringValue], value ) ) {
        [i_pause setTextColor:[NSColor blackColor]];
        // do something with the value
    } else {
        [i_pause setTextColor:[NSColor redColor]];
    }
}

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