iOS 怎么让项目在iphone上只允许竖屏，在ipad上只允许横屏

选中项目->TARGETS->General->勾上Deployment Info iPhone iPad 和下面的Device Orientation
里的四项，和Status Bar Style里的Requires full screen



在appDelegate.m文件的viewController.m里加上以下代码即可

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
  if([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
    return UIInterfaceOrientationPortrait;
  }
    return UIInterfaceOrientationLandscapeRight;
}//页面需要的横屏方向
//
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
  if([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
    return UIInterfaceOrientationMaskPortrait;
  }
    return UIInterfaceOrientationMaskLandscapeRight;
}//页面支持屏幕横屏的方向
 
// 改变页面屏幕方向的方法
- (void)forceToOrientation:(UIDeviceOrientation)orientation{
  NSNumber *orientationUnknown = [NSNumber numberWithInt:0];
  [[UIDevice currentDevice] setValue:orientationUnknown forKey:@"orientation"];
  NSNumber *orientationTarget = [NSNumber numberWithInt:orientation];
  [[UIDevice currentDevice] setValue:orientationTarget forKey:@"orientation"];
}