实现委托方法，但仍然收到警告？

Question

I'm getting a peculiar warning, specifically this one:

warning: class does not implement the 'UIWebViewDelegate' protocol

... when I have these methods in my application:

-(void)webViewDidStartLoad {
    ...
}

-(void)webViewDidFinishLoad {
    ...
}

... and even after setting the UIWebView's delegate to self , I still get this warning, and the methods are never called ( NSLog provides no results.)

Can anyone pinpoint what is happening here? Thanks in advance!

Answer 1

I don't think your delegate methods are correct. Shouldn't they be:

- (void)webViewDidStartLoad:(UIWebView *)webView
{
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
}

Answer 2

As '@No on in particular' says, your methods aren't declared correctly. That is why the methods aren't called at all.

The warning has a different reason. It is because your interface definition doesn't declare that it implements the UIWebViewDelegate protocol.

@interface MyClass : NSObject <UIWebViewDelegate> {
...
}
...
@end

Whether or not the interface declares the protocol or not is actually of no consequence at runtime, it is just a hint to the compiler that allows it to issue warnings like the one you are seeing, or warnings if you don't implement the methods.