UIButton * backButton = [UIButton buttonWithType:UIButtonTypeCustom];
backButton.frame = CGRectMake(0, 0, 60, 44);
[backButton setImage:[UIImage imageNamed:@"back_btn_bg.png"] forState:UIControlStateNormal];
[backButton setTitle:@"Back"forState:UIControlStateNormal];
[backButton setTitleEdgeInsets:UIEdgeInsetsMake(-1, -55, 0, 0)];
[backButton.titleLabel setFont:[UIFont boldSystemFontOfSize:14.0]];
[backButton setTitleColor:[UIColor colorWithRed:233.0/255.0 green:220.0/255.0 blue:207.0/255.0 alpha:1.0]
forState:UIControlStateNormal];
UIBarButtonItem *backNavigationItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
// 调整 leftBarButtonItem 在 iOS7 下面的位置
if(([[[UIDevice currentDevice] systemVersion] floatValue]>=7.0?20:0)){
UIBarButtonItem *negativeSpacer = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace
target:nilaction:nil];
negativeSpacer.width = -10;
self.navigationItem.leftBarButtonItems = @[negativeSpacer, backNavigationItem];
}else
self.navigationItem.leftBarButtonItem = backNavigationItem;
