IOS 7 以上系统导航栏：
[[UINavigationBar appearance] setTintColor:[UIColor whiteColor]]; // 返回按钮颜色
[UINavigationBar appearance].barTintColor = YK_BUTTON_COLOR; //背景颜色
[[UINavigationBar appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor],NSForegroundColorAttributeName,[UIFont boldSystemFontOfSize:17],NSFontAttributeName, nil]]; //标题title属性
IOS6以上自定义导航栏：
/*自定义标题*/
UILabel *vTitleLable = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 200, 21)];
vTitleLable.font = [UIFont boldSystemFontOfSize:17];
vTitleLable.textColor = [UIColor whiteColor];
vTitleLable.textAlignment = NSTextAlignmentCenter;
vTitleLable.backgroundColor = [UIColor clearColor];
vTitleLable.text = _titleStr;
[self.navigationItem setTitleView:vTitleLable]; /*自定义返回按钮*/
UIBarButtonItem *vLeftButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(backButtonClicked:)];
self.navigationItem.leftBarButtonItem = vLeftButtonItem;
[vLeftButtonItem release];