iOS义导航栏字体、颜色

UILabel *titleText = [[UILabel alloc] initWithFrame: CGRectMake(kWidth/2 -60, 0, 120, 50)];
titleText.backgroundColor = [UIColor clearColor];
titleText.textAlignment = NSTextAlignmentCenter;
titleText.textColor=[UIColor whiteColor];
[titleText setFont:[UIFont systemFontOfSize:17.0]];
[titleText setText:@"我的"];
self.navigationItem.titleView = titleText;