Xcode -仅数字

Question

这是我的整张床单，我有点迷路了。我的动作btnResult运行得很好，并且得到了我想要的结果。但是，如果用户只输入数字，我需要执行该操作，否则会收到一条错误消息。

你能把这张纸写完吗?这样我就明白你的意思了。

    - (IBAction)btnResult:(id)sender
    {
        float sum = (_tf1.floatValue * (_tf3.floatValue + 1) - (_tf2.floatValue * _tf3.floatValue));

        float divideOne = sum/3;
        float divideTwo = sum/3*2;


        float value1 = divideOne;
        int intValue1 = (int)value1;
        float fractional1 = fmodf(value1, (float)intValue1);

        if(fractional1 > .5f)
            intValue1++;


        float value2 = divideTwo;
        int intValue2= (int)value2;
        float fractional2 = fmodf(value2, (float)intValue2);

        if(fractional2 > .5f)
            intValue2++;


        _lblResult.floatValue = intValue1;
        _lblResult2.floatValue = intValue2;

        _lblAbove.hidden = NO;
        _lblBelow.hidden = NO;

        _lblResult.hidden = NO;
        _lblResult2.hidden = NO;
    }

Answer 1

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

See this answer for the working example

Answer 2

您需要将UITextField的Delegate设置为self，并实现以下委托方法：

-(BOOL)isNumeric:(NSString*)inputString
{
    NSCharacterSet *cs=[[NSCharacterSet characterSetWithCharactersInString:@"0123456789"] invertedSet];
    NSString *filtered;
    filtered = [[inputString componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
    return [inputString isEqualToString:filtered];
}


-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    // Check for non-numeric characters
    return [self isNumeric:textField.text];
}

享受:)