ios如何让启动页（闪屏页）强制竖屏，而进入App后允许横屏和竖屏

1、修改App-info.plist(在XCode中General中设置 一样的效果)

UISupportedInterfaceOrientations

    UIInterfaceOrientationPortrait

2、AppDelegate中：

- (UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window {
  return UIInterfaceOrientationMaskAllButUpsideDown;
}

参考：https://www.coder4.com/archives/5406