UIBarButtonItem *temporaryBarButtonItem = [[UIBarButtonItem alloc] init]; 
 temporaryBarButtonItem.title = @"返回"; 
 self.navigationItem.backBarButtonItem = temporaryBarButtonItem; 
 [temporaryBarButtonItem release];   

UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" 
       style:UIBarButtonItemStyleBordered 
       target:self 
       action:@selector(backToPrevious)]; 
   
  self.navigationItem.leftBarButtonItem = backButton; 
  [backButton release]; 
 
- (void)backToPrevious 
{ 
  [self.navigationController popViewControllerAnimated:YES]; 
} 

UIButton *leftButton = [[UIButtonalloc] initWithFrame:CGRectMake(0, 0, 60, 40)]; 
  [leftButton setTitle:@"返回"forState:UIControlStateNormal]; 
  [leftButton setImage:[UIImageimageNamed:@"UINavigationBar.png"] forState:UIControlStateNormal]; 
  [leftButton setImage:[UIImageimageNamed:@"UINavigationBar.png"] forState:UIControlStateHighlighted]; 
  [leftButton addTarget:selfaction:@selector(leftAction:) forControlEvents:UIControlEventTouchUpInside]; 
  UIBarButtonItem *leftItem = [[UIBarButtonItemalloc] initWithCustomView:leftButton]; 
  [leftButton release]; 
  self.navigationItem.leftBarButtonItem = leftItem; 
  [leftItem release];