使用 NSNumberFormatter(英语:NSNumberFormatter)设置十进制数的格式

Question

您好，我需要格式化用户在应用程序中输入的十进制数。

100.  = 100
90.00  = 90
90.1  = 90.1
90.22 = 90.22
90.227 = 90.23

我应该如何使用 NSNumberFormatter来实现这一点。

我使用此自定义如果其他条件实现了相同的目标

if ([cell.textField.text rangeOfString:@"."].location != NSNotFound)
    {
        NSString *strAfterDecimal = [cell.textField.text componentsSeparatedByString:@"."].lastObject;
        NSInteger count = [strAfterDecimal length];
        if(count == 0)
        {
            customField.value = [cell.textField.text
                                 stringByReplacingOccurrencesOfString:@"." withString:@""];
        }
        else if(count == 1 || count == 2)
        {
            if([strAfterDecimal integerValue] > 0)
            {
                customField.value = cell.textField.text;
            }
            else
            {
                customField.value = [cell.textField.text componentsSeparatedByString:@"."].firstObject;
            }
        }
        else if(count > 2)
        {
            if([strAfterDecimal integerValue] > 0)
            {
                customField.value = [NSString stringWithFormat:@"%0.2f",[cell.textField.text floatValue]];
            }
            else
            {
                customField.value = [cell.textField.text componentsSeparatedByString:@"."].firstObject;
            }
        }
    }

我需要调整代码的大小。根据客户的说法，如果苹果提供的默认功能可以执行操作，我无法输入额外的代码

Answer 1

这非常简单

NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.maximumFractionDigits = 2;
NSNumber *number = [formatter numberFromString:cell.textField.text];
NSString *numberString =  [formatter stringFromNumber:number];
if (numberString == nil) numberString = @"0";
NSLog(@"%@", numberString);

Swift 版本有点复杂，因为您必须安全地解开选项。

let formatter = NumberFormatter()
formatter.maximumFractionDigits = 2
let numberString : String
if let text = cell.textField.text,
    let number = formatter.number(from: text),
    let string = formatter.string(from: number) {
    numberString =  string
} else {
    numberString = "0"
}
print(numberString)