設置一個UITextField的值

Question

我有一個UITextField會顯示一些像「rocky」的值。如果我從文本字段中刪除該文本，那麼我希望字段文本立即變回原始文本。

Answer 1

- (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 2

Intially添加的NSString *則strName作爲類object.in viewDidLoad中添加此

strName = @"Rocky"; 

現在

- (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 
{ 
    if(textField.length==0) { 
     txtProjectName.text=@"rocky"; 
     return NO; 
    } 
    return YES; 
} 

試試這個。

Answer 4

你需要一個小的變化看我的回答：

- (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; 

}

你可以注意到difference.Just返回NO爲你空字符串的情況。