由于“内存压力”导致的iOS UIImagePNGRepresentation崩溃

Question

我在我的视图控制器中有UIImagePicker和UICollectionView。由于“内存压力”，我正在拍照并在第4张照片（这也是收集视图中的新行）应用程序崩溃。 UIImagePicker代表：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{ 
    // Do picture get here 
    NSError *error; 
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage]; 
    NSData *imageData = UIImagePNGRepresentation(image); 
    NSNumber *imageNumber = [NSNumber numberWithInteger:[databaseManagementService selectTaskPictures].count]; 
    NSString *imageName = [[imageNameDefault stringByAppendingString:[NSString stringWithFormat:objectFormat, imageNumber]] stringByAppendingString:extensionPNG]; 

    // Do picture save to documents directory here 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 
    NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:imageName]; 
    [imageData writeToFile:savedImagePath atomically:NO]; 

    // Do UIImagePicker dismiss here 
    [picker dismissViewControllerAnimated:YES completion:nil]; 

    // Do picture details save to database here 
    TaskManagerTaskPicture *taskPicture = [[TaskManagerTaskPicture alloc] init]; 

    taskPicture.filename = imageName; 
    taskPicture.id = imageNumber; 
    taskPicture.title = imageName; 

    taskPicture.pictureID = self.taskObject.id; 
    taskPicture.taskID = self.taskObject.id; 
    taskPicture.locationID = self.taskObject.location.id; 

    [databaseManagementService insertTaskPictureObject:taskPicture andError:&error]; 

    // Do task picture update here 
    // Do task object SELECT here 
    self.taskObject = [databaseManagementService selectTaskWithID:self.taskObject.id]; 

    // Do task picture objects retreive from task object here 
    self.taskPictureObjects = [self.taskObject.taskPicture allObjects]; 

    // Do collection data reload here 
    [self.taskPicturesCollectionView reloadData]; 
} 

到现在为止我已经开张，并意识到，麻烦由线浇熄：

NSData *imageData = UIImagePNGRepresentation(image); 

没有人有任何想法如何解决这个问题？

Answer 1

你能更好地解释你的应用程序的流程吗？

但是尝试执行此代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{ 
    // Do picture get here 

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{ 
     NSError *error; 
     UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage]; 
     NSData *imageData = UIImagePNGRepresentation(image); 

     NSNumber *imageNumber = [NSNumber numberWithInteger:[databaseManagementService selectTaskPictures].count]; 
     NSString *imageName = [[imageNameDefault stringByAppendingString:[NSString stringWithFormat:objectFormat, imageNumber]] stringByAppendingString:extensionPNG]; 

     // Do picture save to documents directory here 
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
     NSString *documentsDirectory = [paths objectAtIndex:0]; 
     NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:imageName]; 
     [imageData writeToFile:savedImagePath atomically:YES]; 
     dispatch_async(dispatch_get_main_queue(), ^{ 
      // Do UIImagePicker dismiss here 
      [picker dismissViewControllerAnimated:YES completion:nil]; 

      // Do picture details save to database here 
      TaskManagerTaskPicture *taskPicture = [[TaskManagerTaskPicture alloc] init]; 

      taskPicture.filename = imageName; 
      taskPicture.id = imageNumber; 
      taskPicture.title = imageName; 

      taskPicture.pictureID = self.taskObject.id; 
      taskPicture.taskID = self.taskObject.id; 
      taskPicture.locationID = self.taskObject.location.id; 

      [databaseManagementService insertTaskPictureObject:taskPicture andError:&error]; 

      // Do task picture update here 
      // Do task object SELECT here 
      self.taskObject = [databaseManagementService selectTaskWithID:self.taskObject.id]; 

      // Do task picture objects retreive from task object here 
      self.taskPictureObjects = [self.taskObject.taskPicture allObjects]; 

      // Do collection data reload here 
      [self.taskPicturesCollectionView reloadData]; 
     }); 
    }); 

}