Question

我想从解析中删除照片。我怎么能这样做呢？它看起来很简单，但我做不到，并没有真正的资料来说明如何去做。这是我的保存代码。我正在保存一个名为Topc的课程。

- (void)uploadImage:(NSData *)imageData
{
    PFFile *imageFile = [PFFile fileWithName:@"TopsImage.jpg" data:imageData];

    HUD = [[MBProgressHUD alloc] initWithView:self.view];
    [self.view addSubview:HUD];

    // Set determinate mode
    HUD.mode = MBProgressHUDModeDeterminate;
    HUD.delegate = self;
    HUD.labelText = @"Uploading";
    [HUD show:YES];

    // Save PFFile
    [imageFile saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (!error) {
            //Hide determinate HUD
            [HUD hide:YES];

            // Show checkmark
            HUD = [[MBProgressHUD alloc] initWithView:self.view];
            [self.view addSubview:HUD];

            // The sample image is based on the work by http://www.pixelpressicons.com, http://creativecommons.org/licenses/by/2.5/ca/
            // Make the customViews 37 by 37 pixels for best results (those are the bounds of the build-in progress indicators)
            HUD.customView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"37x-Checkmark.png"]];

            // Set custom view mode
            HUD.mode = MBProgressHUDModeCustomView;

            HUD.delegate = self;

            // Create a PFObject around a PFFile and associate it with the current user
            PFObject *userPhoto = [PFObject objectWithClassName:@"Topc"];
            [userPhoto setObject:imageFile forKey:@"imageFile"];

            // Set the access control list to current user for security purposes
            userPhoto.ACL = [PFACL ACLWithUser:[PFUser currentUser]];

            PFUser *user = [PFUser currentUser];
            [userPhoto setObject:user forKey:@"user"];

            [userPhoto saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
                if (!error) {
                    [self refresh:nil];
                }
                else{
                    // Log details of the failure
                    NSLog(@"Error: %@ %@", error, [error userInfo]);
                }
            }];
        }
        else{
            [HUD hide:YES];
            // Log details of the failure
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    } progressBlock:^(int percentDone) {
        // Update your progress spinner here. percentDone will be between 0 and 100.
        HUD.progress = (float)percentDone/100;
    }];
}

Answer 1

我在PFFile上写了一个允许你更新文件的类别，这意味着删除旧文件，然后上传新文件同名。我原本以为替换关联对象中的文件会删除旧文件，但它并没有因为我的数据使用量奇怪地增加。

+(void)updateFileWithName:(NSString*)name data:(NSData*)imageData completion:(void(^)(PFFile* file))completion
{
NSString* endpoint = [NSString stringWithFormat: @"https://api.parse.com/1/files/%@", name];
NSURL* url = [NSURL URLWithString:endpoint];
NSMutableURLRequest* req = [NSMutableURLRequest requestWithURL:url];

[req setHTTPMethod:@"DELETE"];
[req setValue:kParseApplicationKey forHTTPHeaderField:@"X-Parse-Application-Id"];
[req setValue:kParseMasterKey forHTTPHeaderField:@"X-Parse-Master-Key"];

NSLog(@"Updating file: %@", name);
[NSURLConnection sendAsynchronousRequest:req
                                   queue:[NSOperationQueue currentQueue]
                       completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
                           NSLog(@"Deleted old file");
                           PFFile* file = [PFFile fileWithName:name data:imageData];
                           [file saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
                               NSLog(@"Saved new file");
                               completion(file);
                           }];

                       }];
}

您可以通过删除NSURLConnection完成处理程序中的块

轻松更改此选项以删除文件

Answer 2

[ParsePhotoPFObject deleteEventually];

Answer 3

首先要删除图片或完整的行，您需要触发查询从Parse db中获取它，如下所示：

PFQuery *query = [PFQuery queryWithClassName:@"Topc"];

[query whereKeyExists:@"imageFile"];   //Change this condition to fetch the row.

[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error)
{
    if (!error) {
        NSLog(@"Successfully retrieved: %@", object);

     //This might work as I searched for this deleting image but there is no method to do so.
     //So a way would be is to get that object and then setting nil value in it's place.
     //Else if u want to delete the entire row then u could simply type, [object deleteInBackground]
        object[@"imageFile"] = [NSNull null];  
    }
    else
    {
        NSLog(@"Error: %@", [error localizedDescription]);
    }
}];

此外，您可以follow below link for deleting PFFILE

Answer 4

在您的代码中，您分两步添加图片：

上传PFFile（JPG文件）
创建指向步骤1中的PFFile的userPhoto（TopC）对象

您没有说出“删除”的含义，因此您有两个选择：

仅删除userPhoto对象，并保留文件

或

删除userPhoto对象和文件

如果你想保留文件供以后使用，你只需在userPhoto类上调用deleteInBackground。

如果要删除两者，则应首先删除带有deleteInBackgroundWithBlock的文件，然后在块中，如果成功，则删除userPhoto：

PFFile *imageFile = userPhoto[@"imageFile"];

[imageFile deleteInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
  if (succeeded) {
    // Successfully deleted the image file. Now delete userPhoto:
    [userPhoto deleteInBackground];

  }
}];

从解析中删除照片

4 个答案: