iphone - 设置 UITextField 的值

Question

我有一个 UITextField 会显示一些像“rocky”这样的值。如果我从文本字段中删除此文本，那么我希望字段文本立即更改回原始文本。

Answer 1

你需要一点改变，看看我的回答：

- (BOOL)textField:(UITextField *)theTextField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
if([newString isEqualToString:@""]){
    textField.text=@"rocky";
    return NO;
}

return YES;

}

您可以注意到差异。只需为您的空字符串案例返回 NO。

Answer 2

最初添加NSString *strName作为类 object.in viewDidLoad 添加这个

  strName = @"Rocky";

现在

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
   if([[string stringByReplacingOccurrencesOfString:@" "
                                                    withString:@""] isEqualToString:@""]){
     textField.text=strName;
    }
    else
    {
      strName = text; //change name here for keeping record
    }
    return YES; 
}

Answer 3

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
    if(newString.length==0) {
        txtProjectName.text=@"rocky";
        textField.userInteractionEnabled=NO;
        return NO;
    }
    return YES;
}

Answer 4

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if(textField.length==0) {
        txtProjectName.text=@"rocky";
        return NO;
    }
    return YES;
}

尝试这个。