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完成选择媒体信息与信息返回空值照片。

iphoneuiimagecamerauiimagepickercontroller
30

我正在努力捕获使用4.0返回的图像

- (void)imagePickerController:(UIImagePickerController *)picker 
    didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    [[picker parentViewController] dismissModalViewControllerAnimated:YES]; 

    // MediaType can be kUTTypeImage or kUTTypeMovie. If it's a movie then you
    // can get the URL to the actual file itself. This example only looks for images.
    //   
    NSString* mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    // NSString* videoUrl = [info objectForKey:UIImagePickerControllerMediaURL];

    // Try getting the edited image first. If it doesn't exist then you get the
    // original image.
    //
    if (CFStringCompare((CFStringRef) mediaType,  kUTTypeImage, 0) == kCFCompareEqualTo) {               
        UIImage* picture = [info objectForKey:UIImagePickerControllerEditedImage];
        if (!picture)
            picture = [info objectForKey:UIImagePickerControllerOriginalImage];             

        // **picture is always nil
            // info dictionary count = 1


    }

}

发生的情况是info字典总是返回单个条目：

{ UIImagePickerControllerMediaType = "public.image";

这很好，但从未有过图像。
我正在使用论坛中的一个很好的示例来做到这一点，我相信调用是正确的，但从未有过图像。
提前致谢！
有人愿意接手吗？这个项目将会获得巨大的声望提升！！！ - Rob Bonner
8个回答
53

我知道这是很久之前的事情，但我为此苦苦挣扎了几个小时，并发现了这个站点和iphonedevsdk.com上有许多类似的问题，但从未找到一个可行的答案。

总结一下，如果图片是从相机胶卷/照片库中选择的，则可以正常工作，但如果是使用相机拍摄的新照片，则永远不起作用。好吧，这就是如何使它同时适用于两者：

在您尝试对信息字典进行任何操作之前，您必须先解除并释放UIImagePickerController。要非常清楚：

这样做是不起作用的：

- (void)imagePickerController:(UIImagePickerController *)picker 
                      didFinishPickingMediaWithInfo:(NSDictionary *)info {

          // No good with the edited image (if you allowed editing)
  myUIImageView.image = [info objectForKey:UIImagePickerControllerEditedImage];
          // AND no good with the original image
  myUIImageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];
          // AND no doing some other kind of assignment
  UIImage *myImage = [info objectForKey:UIImagePickerControllerEditedImage];

  [picker dismissModalViewControllerAnimated:YES];
  [picker release];
}

在所有这些情况下，图像将为nil。

然而，通过先释放UIImagePickerController的魔力...

这个方法是可行的:

- (void)imagePickerController:(UIImagePickerController *)picker 
                      didFinishPickingMediaWithInfo:(NSDictionary *)info {

  [picker dismissModalViewControllerAnimated:YES];
  [picker release];

          // Edited image works great (if you allowed editing)
  myUIImageView.image = [info objectForKey:UIImagePickerControllerEditedImage];
          // AND the original image works great
  myUIImageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];
          // AND do whatever you want with it, (NSDictionary *)info is fine now
  UIImage *myImage = [info objectForKey:UIImagePickerControllerEditedImage];
}

非常简单，但就是这样。

13
你是认真的吗？！这就是我的问题所在吗！天哪。*晕倒*。 - Stephen Furlani
我还没有尝试过，但是有几个选项可能是可行的。第一个是复制信息字典 - NSDictionary *infoDictionary = [NSDictionary dictionaryWithDictionary:info] - 然后将选择器设置为nil - picker = nil。不确定这是否有效。另一个几乎肯定会起作用的选项是在Xcode中为图像选择代码创建一个单独的文件，并将该文件设置为不使用ARC，保留此处的解决方案。 - Matthew Frederick
谢谢，我已经解决了，但是方法有些不同。我在设置UIImage后关闭了相机。我不知道这可能是iOS上的一个错误。 - John Paul Manoza
哇，我遇到了类似的问题，这个解决方法很好用。现在我很好奇为什么它有效？ - Chan Jing Hong
17

尽管Matthew Frederick的答案最受欢迎并长期以来一直是适当的回应，但自iOS 5.0起，苹果公司提供了dismissViewControllerAnimated:completion:来替换现在已经弃用（自iOS 6.0起）的dismissViewControllerAnimated:。

在完成块中执行图像信息字典检索将对所有人都更有意义。

以他上面的示例为例，现在看起来会是这样的：

- (void)    imagePickerController:(UIImagePickerController *)picker 
    didFinishPickingMediaWithInfo:(NSDictionary *)info 
{
    [picker dismissViewControllerAnimated:YES completion:^{
          // Edited image works great (if you allowed editing)
        myUIImageView.image = [info objectForKey:UIImagePickerControllerEditedImage];
          // AND the original image works great
        myUIImageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];
          // AND do whatever you want with it, (NSDictionary *)info is fine now
        UIImage *myImage = [info objectForKey:UIImagePickerControllerEditedImage];
    }];
}
1
你确定是 [picker dismissModalViewControllerAnimated:YES completion: 而不是 [picker dismissViewControllerAnimated:YES completion:^(void) 吗？ - James Dunay
2
这对我来说仍然产生了一个nil结果，在iPad模拟器（iOS 6.1）中运行iPhone应用程序。 - Desty
实际上，这似乎是自iOS 5以来iPad模拟器中存在已久的错误 - 即使在真实设备上似乎可以工作。奇怪。因此，唯一的解决方案是使用资产库... - Desty
4

我尝试了上述所有方法，但在iPad 6.0/6.1模拟器上没有成功，然而我发现信息中包含“UIImagePickerControllerReferenceURL”键，这是我的代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
  [picker dismissViewControllerAnimated:YES completion:NULL];

  UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage];
  if(NULL == image){
      [MyImageLoader loadImageFromAssertByUrl:[info objectForKey:@"UIImagePickerControllerReferenceURL"]
                                   completion:^(UIImage* img){
                                        //img not null here
                                   }];
  }else{
      //image not null here
  }
}

loadImageFromAssertByUrl的代码如下:

+(void) loadImageFromAssertByUrl:(NSURL *)url completion:(void (^)(UIImage*)) completion{
  ALAssetsLibrary *assetLibrary=[[ALAssetsLibrary alloc] init];
  [assetLibrary assetForURL:url resultBlock:^(ALAsset *asset) {
      ALAssetRepresentation *rep = [asset defaultRepresentation];
      Byte *buffer = (Byte*)malloc(rep.size);
      NSUInteger buffered = [rep getBytes:buffer fromOffset:0.0 length:rep.size error:nil];
      NSData *data = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];
      UIImage* img = [UIImage imageWithData:data];
      completion(img);
  } failureBlock:^(NSError *err) {
      NSLog(@"Error: %@",[err localizedDescription]);
  }];
}
谢谢！我简直不敢相信我们需要这样做来解决iPad模拟器中至少一年前就报告的错误，但至少可以绕过它... - Desty
2

有些版本的XCode和Mountain Lion存在已知的bug。请检查控制台是否出现以下信息：

2013-01-17 21:36:34.946 3sure-ios[5341:1803] Named service 'com.apple.PersistentURLTranslator.Gatekeeper' not found. assetsd is down or misconfigured. Things will not work the way you expect them to.

如果出现上述信息，则可能无法正常工作。请在实际的iOS设备上检查您的应用程序。

尽管如此，重新启动模拟器和XCode似乎可以解决该问题。

我没有看到这个错误，但在模拟器上图像为空，在设备上却可以运行。 - Justin Meiners
0

使用

[[UIImagePickerController alloc] init];

而不是 

[[UIImagePickerController alloc] initWithNibName:(NSString *) bundle:(NSBundle *)];
0
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{

    [picker dismissViewControllerAnimated:YES completion:NULL];
    //Image picker for nil value 
    UIImage* selectedImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    NSLog(@"my Info :: %@", info);

    if(NULL == selectedImage){
      UIImage * selectedImage =  [PhotoViewController loadImageFromAssertByUrl:[info objectForKey:@"UIImagePickerControllerReferenceURL"]
                                     completion:^(UIImage * selectedImage){
                                         //img not null here
                                         NSLog(@"img2 ::: %@", selectedImage);
                                         uploadImg.image = selectedImage;
                                         [self.view addSubview:PermissionView];
                                     }];
    }else{
        //image not null here
        NSLog(@"Up IMG00 :: %@", uploadImg.image);
        NSLog(@"Sel IMG00 :: %@", selectedImage);
        uploadImg.image = [selectedImage retain];
        NSLog(@"Up IMG22 :: %@", uploadImg.image);
        NSLog(@"Sel IMG22 :: %@", selectedImage);

    }
}


+(UIImage *) loadImageFromAssertByUrl:(NSURL *)url completion:(void (^)(UIImage*)) completion{


    __block UIImage* img;

    ALAssetsLibrary *assetLibrary=[[ALAssetsLibrary alloc] init];

    [assetLibrary assetForURL:url resultBlock:^(ALAsset *asset) {
        ALAssetRepresentation *rep = [asset defaultRepresentation];
        Byte *buffer = (Byte*)malloc(rep.size);
        NSUInteger buffered = [rep getBytes:buffer fromOffset:0.0 length:rep.size error:nil];
        NSData *data = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];
        img = [UIImage imageWithData:data];
        completion(img);
        NSLog(@"img ::: %@", img);
    } failureBlock:^(NSError *err) {
        NSLog(@"Error: %@",[err localizedDescription]);
    }];

    return img;
}
1
我在iPad Air和iOS 8上遇到了同样的问题，但是我通过这些代码解决了我的问题。谢谢。 - dobiho
0

我有相同的症状，但在我的情况下，它最终证明我在UIImagePickerController层次结构中有某个类别覆盖了"uuid"或"setUUID"？ 我想CoreData需要这些方法，否则它会变得非常非常混乱，而资源库是全部CoreData内容。

-1
需要按照以下步骤进行：
1）创建UIActionSheet
2）选择必要的资源类型-加载资源
3）didFinishPickingMediaWithInfo-从接收到的图像字典中设置图像
    - (IBAction)actionButtonUpload:(id)sender {

             UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self 

cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"Camera",@"Photo Library", nil];

         [actionSheet showInView:self.view];

    }

    #pragma mark -- UIActionSheet Delegate
    -(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{

        UIImagePickerController *picker = [[UIImagePickerController alloc] init];

        picker.delegate = self;
        picker.allowsEditing = YES;
        UIAlertView *alert;


        switch (buttonIndex) {
            case 0:
                if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

                    NSLog(@"No camera!");
                    picker.sourceType = UIImagePickerControllerSourceTypeCamera;
                    [self presentViewController:picker animated:YES completion:NULL];


                } else {

                    alert = [[UIAlertView alloc]initWithTitle:@"Alumnikonnect" message:@"Camera is not available, please select a different media" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];

                    [alert show];

                }
                break;
            case 1:

                if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

                    picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
                    [self presentViewController:picker animated:YES completion:NULL];


                } else {

                    alert = [[UIAlertView alloc]initWithTitle:@"Alumnikonnect" message:@"Photolibrary is not available, please select a different media" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];

                    [alert show];

                }

                break;

        }

    }


    #pragma mark - Image picker delegate

    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
    {
          self.imageEventPic.layer.cornerRadius =   self.imageEventPic.frame.size.height /2;
          self.imageEventPic.layer.masksToBounds = YES;
          self.imageEventPic.layer.borderWidth = 0;
          self.imageEventPic.layer.borderWidth = 1.0f;
          self.imageEventPic.layer.borderColor = [UIColor colorWithRed:0.212 green:0.255 blue:0.302 alpha:1.000].CGColor;


        self.labelUploadPic.hidden = YES;

        self.imageEventPic.image =  info[UIImagePickerControllerOriginalImage];

        [self dismissViewControllerAnimated:YES completion:NULL];

    }


    - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
    {
        [self dismissViewControllerAnimated:YES completion:NULL];

    }

    -(UIImage*)imageWithImage:(UIImage*)image
                 scaledToSize:(CGSize)newSize;
    {
        UIGraphicsBeginImageContext( newSize );

        [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

        UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

        return newImage;

    }
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