navigationBar 背景色

 if ([[[UIDevice currentDevice]systemVersion]floatValue] >= 7.0) {
        [[UINavigationBar appearance] setBarTintColor:[UIColor colorWithHexString:@"0b6aff"]];
    }
    else
    {
        self.navigationBar.tintColor = [UIColor colorWithHexString:@"0b6aff"];
    }