ref： http://www.cnblogs.com/niit-soft-518/p/5611298.html
实际的项目需求。root是TabBarController，里面有4个navigationController，现在要锁死所有页面的屏幕方向
try 1:继承navigation：然并卵
try 2: 继承tabbarcontroller：然并卵
try 3: 继承navigation，tabbar：然并卵
result：iOS9设置无效，iOS8以下，只需设置tabbar，只设置navigation没用
最后：iOS9以下的锁死实现：
#import "RootTabbarViewController.h"
@interface RootTabbarViewController ()
@end
@implementation RootTabbarViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
//是否可以旋转
- (BOOL)shouldAutorotate
{
NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults];
//读取保存的数据
NSUInteger *isLock =[defaults integerForKey:@"ScreenLockSetting"];
if(isLock==YES){
return NO;
}else return YES;
//return isLock;
}
//优先竖屏
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
return UIInterfaceOrientationPortrait;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}