Iphone iOS 7中的UIImagePickerControllerSourceTypePhotoLibrary不工作

当我升级到iOS7时，当我从应用程序访问照片库时，我的应用程序显示一个空的视图控制器。它使用的是较旧的框架

 UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
    imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
    imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    imagePickerController.delegate = self;
    self.imagePicker = imagePickerController;
    //self.imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    [self presentViewController:self.imagePicker animated:YES completion:nil];

---

请直接使用此代码

UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
imagePickerController.delegate = self;
[self presentViewController:imagePickerController animated:YES completion:nil];

当此代码运行时，“应用程序”将访问您的照片消息，当您单击“确定”时，将显示所有图像

谢谢