NSNumberFormatter setFormat误差

Question

正在开发我的第一个iOS应用程序。我认为这段代码应该可以工作，但是我得到了以下错误。也许我漏掉了进口什么的？

No visible @interface for 'NSNumberFormatter' declares the selector'setFormat'

NSNumberFormatter* formatter = [[NSNumberFormatter alloc] init];
[formatter setFormat:@"#0.00"];

Answer 1

你不能叫setFormat: for NSNumberFormatter。

一些示例代码：

NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.numberStyle = NSNumberFormatterDecimalStyle;
NSString *string = [formatter stringFromNumber:[NSNumber numberWithInt:123456789]];
NSLog(@"Formatted number string:%@",string);

numberStyle枚举：

enum {  
    NSNumberFormatterNoStyle = kCFNumberFormatterNoStyle,
    NSNumberFormatterDecimalStyle = kCFNumberFormatterDecimalStyle,
    NSNumberFormatterCurrencyStyle = kCFNumberFormatterCurrencyStyle,
    NSNumberFormatterPercentStyle = kCFNumberFormatterPercentStyle,
    NSNumberFormatterScientificStyle = kCFNumberFormatterScientificStyle,
    NSNumberFormatterSpellOutStyle = kCFNumberFormatterSpellOutStyle
};

为每个numberStyle重新分配：

[1243:403] Formatted number string:123456789
[1243:403] Formatted number string:123,456,789
[1243:403] Formatted number string:￥123,456,789.00
[1243:403] Formatted number string:-539,222,988%
[1243:403] Formatted number string:1.23456789E8
[1243:403] Formatted number string:one hundred twenty-three million four hundred fifty-six thousand seven hundred eighty-nine

Answer 2

您不能像这里提供的那样设置格式。设置数字格式，如下所示

[formatter setNumberStyle:NSNumberFormatterSpellOutStyle];
//or other styles like NSNumberFormatterDecimalStyle,NSNumberFormatterPercentStyle

或者您可以创建一个自定义数字格式，如

[formatter setPositiveFormat:@"#0.00"];

这里提供了一个很好的教程。

http://useyourloaf.com/blog/2012/06/14/using-number-formatters.html