使用UITextField格式化货币 [英] Format currency with UITextField

问题描述

我有一个UITextField，用户将输入一笔金额。我想设置它以便显示用户货币。我可以执行以下操作：

I have a UITextField that the user will enter an amount of money. I want to set it so it will show the users currency. I could do the following:

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    NSNumberFormatter *currencyFormatter = [[[NSNumberFormatter alloc] init] autorelease];
    [currencyFormatter setLocale:[NSLocale currentLocale]];
    [currencyFormatter setMaximumFractionDigits:2];
    [currencyFormatter setMinimumFractionDigits:2];
    [currencyFormatter setAlwaysShowsDecimalSeparator:YES];
    [currencyFormatter setNumberStyle:NSNumberFormatterCurrencyStyle];

    NSNumber *someAmount = [NSNumber numberWithDouble:[textField.text doubleValue]];
    NSString *string = [currencyFormatter stringFromNumber:someAmount];

    textField.text = string;
}

有效。但是我希望它在启动时显示，并且当用户输入金额时。以上代码仅在用户完成该textField时才有效。如何在启动时和用户输入数字时显示该方法中的代码。



我试图将方法更改为shouldChangeTextInRange，但它给出了奇怪的效果。

That works. But I want it to show on startup, and while the user is typing the amount. The above code only works when the user is finished with that textField. How can I make the code in that method to show on startup and while the user is entering numbers.

I tried to change the method to shouldChangeTextInRange, but it gives a weird effect.

推荐答案

要在启动时更改某些内容，请在viewDidLoad中运行一些代码。



处理inChangeTextInRange是正确的，如 stackoverflow 所述。



有什么奇怪的效果？



提示1：NSNumberFormatter应该只创建ONCE（高成本对象）

提示2：转换为ARC（编辑 - >转换中的assisent）

To change something on startup you run some code in viewDidLoad.

The handling in shouldChangeTextInRange is correct like instackoverflow described.

What weird effect?

Tip 1: NSNumberFormatter should created only ONCE (high cost object)
Tip 2: convert to ARC (with the assisent in Edit->convert)

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