Question

在我的应用中，我希望用户能够拍照或使用照片库中的照片。当用户点击按钮时，我弹出警报视图，用户可以选择拍摄新照片或照片库中的照片。这是我用过的代码：

    - (void)PictureAlert:(id)sender {

    UIAlertView *AlertDialog;

    // Setting up AlertDialog.
    AlertDialog = [[UIAlertView alloc] initWithTitle:nil 
                                             message:nil 
                                            delegate:self 
                                   cancelButtonTitle:@"Cancel" 
                                   otherButtonTitles:@"Choose From Library", @"Take New Picture", nil];

    [AlertDialog show]; }

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {

    NSString *ButtonTitle = [alertView buttonTitleAtIndex:buttonIndex];

    if ([ButtonTitle isEqualToString:@"Choose From Library"]) {

        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

            // Pick photo.
            UIImagePickerController *picker = [[UIImagePickerController alloc] init];
            picker.delegate = self;
            picker.allowsEditing = YES;
            picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;

            [self presentModalViewController:picker animated:YES];


        } else if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

            // Setting up AlertDialog.
            UIAlertView *AlertDialog;

            AlertDialog = [[UIAlertView alloc] initWithTitle:@"Error accessing photo library" 
                                                     message:@"Device does not support a photo library"  
                                                    delegate:self 
                                           cancelButtonTitle:@"Dismiss" 
                                           otherButtonTitles:nil];

            [AlertDialog show];

        }


    } else if ([ButtonTitle isEqualToString:@"Take New Picture"]) {

        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

            // Take new photo.
            UIImagePickerController *picker = [[UIImagePickerController alloc] init];
            picker.delegate = self;
            picker.allowsEditing = YES;
            picker.wantsFullScreenLayout = YES;
            picker.sourceType = UIImagePickerControllerSourceTypeCamera;

            [self presentModalViewController:picker animated:YES];


        } else if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

            // Setting up AlertDialog.
            UIAlertView *AlertDialog;

            AlertDialog = [[UIAlertView alloc] initWithTitle:@"Error accessing camera" 
                                                     message:@"Device does not support a camera"  
                                                    delegate:self 
                                           cancelButtonTitle:@"Dismiss" 
                                           otherButtonTitles:nil];

            [AlertDialog show];

        }

    }

}

问题在于，如果用户想要拍摄新照片，则会弹出相机界面，然后如果您旋转设备，界面将如下所示： enter image description here

然后当用户将其旋转回来时，突然看起来像这样： enter image description here

一个小问题是相机需要很长时间才能装入。

任何想法都将被赞赏：）

Answer 1

您可能需要考虑的一些事项：

将wantsFullScreenLayout属性设置为YES将导致视图忽略状态栏。但由于您使用的是默认摄像头控件，状态栏会自动隐藏。这是图像底部20像素灰色区域的最可能原因。
默认的相机控件仅设计为纵向模式。由于您的第一张图片看起来像是以某种方式旋转了屏幕，因此您应该查看代码（可能是shouldAutoRotate）并查看为什么要像这样旋转视图。这应该可以解决您在风景画中遇到的变焦问题。
如果您创建UIImagePickerController，将其显示，然后没有引用它以便稍后释放，则会发生内存泄漏。我建议在界面中设置UIImagePickerController，并在viewDidLoad方法中进行设置。尝试：

<强>·H

@interface yourView:UIViewController <UIImagePickerControllerDelegate> {
  UIImagePickerController * picker;
}

<强>的.m

- (void)dealloc; {
  [picker release];
  [super dealloc];
}

- (void)viewDidLoad; {
  [super viewDidLoad];
  picker = [[UIImagePickerController alloc] init];
  picker.delegate = self;
  picker.allowsEditing = YES;
  picker.sourceType = UIImagePickerControllerSourceTypeCamera;
}

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex; {
  NSString *ButtonTitle = [alertView buttonTitleAtIndex:buttonIndex];

  if([ButtonTitle isEqualToString:@"Choose From Library"]){
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){
      picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
      [self presentModalViewController:picker animated:YES];
    }
    else{
      // Setting up AlertDialog.
      UIAlertView *AlertDialog;
      AlertDialog = [[UIAlertView alloc] initWithTitle:@"Error accessing camera" 
                                               message:@"Device does not support a camera"  
                                              delegate:self 
                                     cancelButtonTitle:@"Dismiss" 
                                     otherButtonTitles:nil];
      [AlertDialog show];
      [AlertDialog release];
    }
  }
  else if([ButtonTitle isEqualToString:@"Take New Picture"]){
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
      picker.sourceType = UIImagePickerControllerSourceTypeCamera;
      [self presentModalViewController:picker animated:YES];
    }
    else{
      // Setting up AlertDialog.
      UIAlertView *AlertDialog;
      AlertDialog = [[UIAlertView alloc] initWithTitle:@"Error accessing camera" 
                                               message:@"Device does not support a camera"  
                                              delegate:self 
                                     cancelButtonTitle:@"Dismiss" 
                                     otherButtonTitles:nil];
      [AlertDialog show];
      [AlertDialog release];
    }
  }
}

这应该清理内存泄漏，并改善加载时间。希望有帮助！

Answer 2

如果您使用的是具有当前操作系统的老一代iPhone，例如您正在使用iphone 3G并且将其ios更新为ios5，那么有些时候会发生这种情况，那么您安装的某些应用程序可能会有不同的行为，您可以将应用程序检查到另一个解决问题的装置。

Answer 3

确保使用mainWindow.rootViewController和[vc addChildViewController：]设置视图控制器层次结构。这会将方向信息传播到您需要的位置。

Answer 4

看起来我的项目发生了这种情况，因为您还没有在根视图控制器中编写shouldAutoRotateToInterface：方法。调用UIImagePickerController时，旋转消息一直向下传播到根视图控制器的shouldAutoRotateToInterface委托。您的方法应如下所示：

- (BOOL)shouldAutorotateToInterfaceOrientation(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

当我将项目升级到iOS 5时，我从iOS 3项目借用了我的根视图控制器。 iOS 3没有在视图控制器类中自动编写此方法试试看并告诉我。

当我使用UIImagePickerController时，为什么我的相机界面会很奇怪？

4 个答案: