iOS 调整导航按钮左右间距 苹果怎么调导航键

[self.navigationItem.leftBarButtonItem setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
[UIFont boldSystemFontOfSize:15],NSFontAttributeName, nil] forState:UIControlStateNormal];//设置左边按钮字体的大小
self.navigationController.navigationBar.tintColor = [UIColor grayColor];
    //设置按钮文字的的颜色
[self.navigationController.navigationBar setTitleTextAttributes:
@{NSFontAttributeName:[UIFont systemFontOfSize:19],
NSForegroundColorAttributeName:[UIColor redColor]}];//设置导航栏字体的大小和颜色
self.hidesBottomBarWhenPushed=YES;//设置在push的时候隐藏tabbar
[self.navigationController pushViewController:view1 animated:YES];
self.hidesBottomBarWhenPushed=NO;//设置在返回时候显示按钮