How to change back button from text to image in UINavigationBar

UIBarButtonItem *backButton = [[UIBarButtonItem alloc]  
                               initWithImage:@"rGoBack" 
                     开发者_如何转开发          style:UIBarButtonItemStylePlain  
                               target:nil action:nil];  
self.navigationItem.backBarButtonItem = backButton;  
[backButton release];

I use this source. but It doesn't work. I don't know why not. please..

From the first glance:

initWithImage:@"rGoBack" 

here UIImage parameter required and NSString is passed instead. Try writing something like:

initWithImage:[UIImage imageNamed:@"rGoBack.png"]; // or whatever image name you have