iphone - 我怎样才能摆脱这个警告？

Question

我在 (theTextField.delegate = self;) 行收到一条警告，上面写着“Assigning to 'id from incompatible type Alert Prompt”

- (id)initWithTitle:(NSString *)title message:(NSString *)message delegate:(id)delegate cancelButtonTitle:(NSString *)cancelButtonTitle okButtonTitle:(NSString *)okayButtonTitle
{

    if (self == [super initWithTitle:title message:message delegate:delegate cancelButtonTitle:cancelButtonTitle otherButtonTitles:okayButtonTitle, nil])
    {
        UITextField *theTextField = [[UITextField alloc] initWithFrame:CGRectMake(12.0, 45.0, 260.0, 25.0)]; 
        [theTextField setBackgroundColor:[UIColor whiteColor]]; 
        [self addSubview:theTextField];
        self.textField = theTextField;
        [theTextField release];
        CGAffineTransform translate = CGAffineTransformMakeTranslation(0.0, -25.0); 
        [self setTransform:translate];

        theTextField.backgroundColor = [UIColor clearColor];
        theTextField.borderStyle = UITextBorderStyleRoundedRect;
        theTextField.delegate = self;
    }
    return self;
}

Answer 1

关于此属性在 the docs

@property(nonatomic, assign) id<UITextFieldDelegate> delegate

这意味着，您的类必须符合UITextFieldDelegate 协议(protocol)。
声明可能看起来像这样

@interface MyController : NSObject <UITextFieldDelegate> {