iOS 6中的退格功能和iOS 5 for UITextfield，具有'secure'属性 [英] Backspace functionality in iOS 6 & iOS 5 for UITextfield with 'secure' attribute

问题描述

我有一个 UITextfield 用于输入密码，启用了 SECURE 属性。

I have a UITextfield for entering password with SECURE attribute enabled.

当用户在输入一定数量的字符后点击 UITextfield 之外，然后再次点击回到 UITextfield 进行编辑时，发生以下行为：

When the user taps outside the UITextfield after inputting a certain number of characters, and then taps back again to the UITextfield for editing, the following behavior is taking place:

iOS 5.1
- 当我尝试从 UITextfield 中删除​​一个字符（使用键盘中的 backspace ），删除最后一个字符。

iOS 5.1 -When I try to delete a character(using backspace from keyboard) from the UITextfield, the last character is deleted.

iOS 6.0
- 当我尝试从 UITextfield 中删除​​某个字符时，所有键入的字符都会被删除。

iOS 6.0 -When I try to delete a character from the UITextfield, all typed characters are getting deleted.

我做错了什么，或者这是iOS 6中的错误？

Am I doing something wrong, or is this a bug in iOS 6?

推荐答案

这是iOS6下的预期行为，您不应该更改它。

This is the intended behaviour under iOS6 and you shouldn't probably change it.

如果出于任何原因你真的需要这个，你可以覆盖 UITextField 的委托方法 textField：shouldChangeCharactersInRange：replacementString：并恢复旧行为：

If for whatever reason you really need this, you can override UITextField's delegate method textField:shouldChangeCharactersInRange:replacementString: and restore the old behaviour:

#import "ViewController.h"

@interface ViewController () <UITextFieldDelegate>
@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.passwordField.delegate = self;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (range.location > 0 && range.length == 1 && string.length == 0)
    {
        // iOS is trying to delete the entire string
        textField.text = [textField.text substringToIndex:textField.text.length - 1];
        return NO;
    }
    return YES;
}

@end

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