从NSMutableArray中删除图像

Question

因此，我正在编写的应用程序允许用户从其相机胶卷上传照片，并将其显示在UIImageView中。我有一个“保存”按钮，可以在按下时保存图像。我也有一个“编辑”按钮，点击时，它允许用户点击照片，它将被删除。这是我遇到的问题，图像从视图中删除，但似乎没有从数组中删除。当我关闭并重新启动应用程序时，照片再次出现。我对Objective-C非常陌生，我很惊讶我甚至做到了这一点，所以我在解决如何从数组中删除它的问题。另外，作为一个附注，如果我从相机胶卷中抓取3张图像，删除中间的一张，然后按下保存按钮，关闭并重新启动应用程序后，它只会显示应该显示的2张照片。关于重新启动后图像再次出现的问题仅在先按下保存，然后尝试删除它们时才会出现。

这就是我要如何删除它们。我在每个UIImageView上都有一个不可见的按钮，当按下Edit按钮时，它将取消隐藏它们。我已经标记这两个按钮和UIImageViews的，并且当按下一个按钮，这个火灾：

- (IBAction)deleteButtonPressed:(id)sender { 
    UIAlertView *deleteAlertView = [[UIAlertView alloc] initWithTitle:@"Delete" 
                   message:@"Are you sure you want to delete this photo?" 
                  delegate:self 
                cancelButtonTitle:@"No" 
                otherButtonTitles:@"Yes", nil]; 
    [deleteAlertView show]; 

    int imageIndex = ((UIButton *)sender).tag; 
    deleteAlertView.tag = imageIndex; 
} 

- (UIImageView *)viewForTag:(NSInteger)tag { 
    UIImageView *found = nil; 
    for (UIImageView *view in self.array) { 
     if (tag == view.tag) { 
      found = view; 
      break; 
     } 
    } 
    return found; 
} 

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


    if (buttonIndex != [alertView cancelButtonIndex]) { 

     UIImageView *view = [self viewForTag:alertView.tag]; 
     if (view) { 
      [self.array removeObject:view]; 
     } 

     ((UIImageView *)[self.view viewWithTag:alertView.tag]).image =nil; 
    } 

    [self.user setObject:self.array forKey:@"images"]; 
} 

而且仅作参考，这是我如何保存图像：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)img editingInfo:(NSDictionary *)editInfo { 
     if (imageView.image == nil) { 
      imageView.image = img; 

      [self.array addObject:imageView]; 

      [picker dismissModalViewControllerAnimated:YES]; 
      [self.popover dismissPopoverAnimated:YES]; 

      return; 

     } 

     if (imageView2.image == nil) { 
      imageView2.image = img; 
      NSLog(@"The image is a %@", imageView); 
      [self.array addObject:imageView2]; 

      [picker dismissModalViewControllerAnimated:YES]; 
      [self.popover dismissPopoverAnimated:YES]; 

      return; 
     } 
     ... 
     ... 
     } 

    -(IBAction)saveButtonPressed:(id)sender { 
     NSString *docsDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES) objectAtIndex:0]; 



     for (UIImageView *imageViewToSave in self.array) { 

      NSInteger tag = imageViewToSave.tag; 
      UIImage *image = imageViewToSave.image; 
      NSString *imageName = [NSString stringWithFormat:@"Image%i.png",tag]; 

      NSString *imagePath = [docsDir stringByAppendingPathComponent:imageName]; 

      [UIImagePNGRepresentation(image) writeToFile:imagePath atomically:NO]; 
     } 

    } 

这是我如何加载它们：

-(void)viewDidLoad { 

     self.array = [NSMutableArray array]; 
     NSString *docsDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES) objectAtIndex:0]; 

     NSArray *docFiles = [[NSFileManager defaultManager]contentsOfDirectoryAtPath:docsDir error:NULL]; 

     for (NSString *fileName in docFiles) { 

      if ([fileName hasSuffix:@".png"]) { 
       NSString *fullPath = [docsDir stringByAppendingPathComponent:fileName]; 
       UIImage *loadedImage = [UIImage imageWithContentsOfFile:fullPath]; 

       if (!imageView.image) { 
        imageView.image = loadedImage; 
       } 
       else if (!imageView2.image) { 
        imageView2.image = loadedImage; 
        } 
       else if (!imageView3.image) { 
        imageView3.image = loadedImage; 

       } 

      } 
     } 
    } 

更新：这里是我当前的代码：

- (IBAction)deleteButtonPressed:(id)sender { 
    NSLog(@"Sender is %@", sender); 
    UIAlertView *deleteAlertView = [[UIAlertView alloc] initWithTitle:@"Delete" 
                   message:@"Are you sure you want to delete this photo?" 
                  delegate:self 
                cancelButtonTitle:@"No" 
                otherButtonTitles:@"Yes", nil]; 
    [deleteAlertView show]; 

    int imageIndex = ((UIButton *)sender).tag; 
    deleteAlertView.tag = imageIndex; 
} 

- (UIImageView *)viewForTag:(NSInteger)tag { 
    UIImageView *found = nil; 
    for (UIImageView *view in self.array) { 
     if (tag == view.tag) { 
      found = view; 
      break; 
     } 
    } 
    return found; 
} 

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


    if (buttonIndex != [alertView cancelButtonIndex]) { 

     UIImageView *view = [self viewForTag:alertView.tag]; 
     if (view) { 
      [self.array removeObject:view]; 

      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
      NSString *documentsPath = [paths objectAtIndex:0]; 
      NSString *filePath = [documentsPath stringByAppendingPathComponent:[NSString stringWithFormat:@"Image%i.png",view.tag]]; 
      NSFileManager *fileManager = [NSFileManager defaultManager]; 
      [fileManager removeItemAtPath:filePath error:NULL]; 
     } 

     ((UIImageView *)[self.view viewWithTag:alertView.tag]).image =nil; 
    } 

    [self.user setObject:self.array forKey:@"images"]; 
} 

Answer 1

当您从数组[self.array removeObject:view];删除图像时，您尚未从目录中删除图像本身。

你可能想从array删除对象后，做这样的事情：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsPath = [paths objectAtIndex:0]; 
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"THE_IMAGE_NAME_HERE.png"]; 
NSFileManager *fileManager = [NSFileManager defaultManager]; 
NSError *error; 
[fileManager removeItemAtPath:filePath error:&error]; 

if (error) 
NSLog(@"Error: %@",error); 

Answer 2

您的数组与此无关。无论如何，它会在下一次启动时被覆盖。我不认为你曾经从文件夹中删除你的图像，所以它会在你的viewDidLoad方法的下一次启动时再次读取。