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

您需要进行一些小改动，请参阅我的回答：

- (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。只需为空字符串返回NO。

Answer 2

 - (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 3

最初将 NSString * strName 添加为类object.in viewDidLoad添加此

  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 4

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

试试这个。