保存后 UITableViewCell 和 Coredata 上的 UIImage 的方向发生了变化

Posted 2023-03-05

【中文标题】保存后 UITableViewCell 和 Coredata 上的 UIImage 的方向发生了变化

【英文标题】：Orientation of UIImage on UITableViewCell and Coredata changed after saved

【发布时间】：2012-05-01 06:39:03

【问题描述】：

我在表格的表格详细视图上有以下代码，它允许用户从库中拍照或加载图像到 UIImageView。然后这将使用核心数据保存。 保存后会回到UITable。奇怪的是，保存后UITable上的图片也从纵向变成了横向。我可以知道我的代码是否有问题。

非常感谢

DetailView.m

- (IBAction)editSaveButtonPressed:(id)sender

    // If we are adding a new picture (because we didnt pass one from the table) then create an entry
    if (!currentPicture)
        self.currentPicture = (Pictures *)[NSEntityDescription insertNewObjectForEntityForName:@"Pictures" inManagedObjectContext:self.managedObjectContext];


if (imageField.image)
    
        // Resize and save a smaller version for the table
        float resize = 74.0;
        float actualWidth = imageField.image.size.width;
        float actualHeight = imageField.image.size.height;
        float divBy, newWidth, newHeight;
        if (actualWidth > actualHeight) 
            divBy = (actualWidth / resize);
            newWidth = resize;
            newHeight = (actualHeight / divBy);
         else 
            divBy = (actualHeight / resize);
            newWidth = (actualWidth / divBy);
            newHeight = resize;
        
        CGRect rect = CGRectMake(0.0, 0.0, newWidth, newHeight);
        UIGraphicsBeginImageContext(rect.size);
        [imageField.image drawInRect:rect];
        UIImage *smallImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        // Save the small image version
        NSData *smallImageData = UIImagePNGRepresentation(imageField.image);
        [self.currentPicture setSmallPicture:smallImageData];
    

    //  Commit item to core data
    NSError *error;
    if (![self.managedObjectContext save:&error])
        NSLog(@"Failed to add new picture with error: %@", [error domain]);

    //  Automatically pop to previous view now we're done adding
    [self.navigationController popViewControllerAnimated:YES];


- (IBAction)imageFromAlbum:(id)sender
    takePhotoBtn.hidden=YES;
    choosePhotoBtn.hidden=YES;
    takephoto.hidden=NO;
    imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate = self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
    [self presentViewController:imagePicker animated:YES completion:nil];


//  Take an image with camera
- (IBAction)imageFromCamera:(id)sender
    takePhotoBtn.hidden=YES;
    choosePhotoBtn.hidden=YES;
    takephoto.hidden=NO;
    imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate = self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.cameraDevice = UIImagePickerControllerCameraDeviceRear;
    [self presentViewController:imagePicker animated:YES completion:nil];

TableView.m

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) 
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    

    // Get the core data object we need to use to populate this table cell
    Pictures *currentCell = [pictureListData objectAtIndex:indexPath.row];

    //  Fill in the cell contents
    cell.textLabel.text = [currentCell title];
    cell.detailTextLabel.text = [currentCell desc];
    cell.backgroundColor =  [UIColor colorWithPatternImage:[UIImage imageNamed:@"lightblue.jpg"]];
    //  If a picture exists then use it
    if ([currentCell smallPicture])
    
        cell.imageView.contentMode = UIViewContentModeScaleAspectFit;
        cell.imageView.image = [UIImage imageWithData:[currentCell smallPicture]];
    
    tableView.opaque = NO;
    [tableView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"gray.jpg"]]];

    return cell;

【问题讨论】：

它只发生在真正的 iPhone 上。在模拟器中一切都很好。

【参考方案1】：

您的图像大小调整未考虑图像旋转。我知道的最简单的解决方案：将图像分配给具有所需大小并使用的 UIImageView。

[imgView.layer renderInContext:context];

这会考虑所有可能的方向。

【参考方案2】：

更改以下部分..

CGRect rect = CGRectMake(0.0, 0.0, newWidth, newHeight);
UIGraphicsBeginImageContext(rect.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];//here you can use your image view instead of self,view...
[imageField.image drawInRect:rect];
UIImage *smallImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

希望对你有所帮助..