UIBarButtonItem *bbtn = [[UIBarButtonItem
alloc] initWithTitle:@"返回"
style:UIBarButtonItemStyleBordered
target:nil
action:nil];
UIImage *backBarBtn = [[UIImage
imageNamed:@"return.png"]
resizableImageWithCapInsets:UIEdgeInsetsMake(0.0, 13.0, 0.0, 5.0)];
[bbtn setBackButtonBackgroundImage:backBarBtn
forState:UIControlStateNormal
barMetrics:UIBarMetricsDefault];
self.navigationItem.backBarButtonItem = bbtn;