Question

我认为这非常简单，但我无法弄清楚为什么这些代码不正确。我想从Parse User类中检索一个图像。我的意思是，每个用户都有一个个人资料图片，我存储在“imageFile”列下，我想将它加载到PFImageView。上传工作正常，但我不能检索它。日志显示错误，因为查询没有匹配项。我想要检索的文件存在，所以100％我的查询实现是错误的。我非常感谢任何相关的帮助，谢谢。

非查询版本:(所有版本均在viewDidLoad中实施）

    self.userThumbnail.file = self.currentUser.imageFile;
    [self.userThumbnail loadInBackground];

查询版本

  PFQuery *queryImage = [PFQuery queryWithClassName:@"User"];

 [queryImage whereKey:@"imageFile" equalTo:self.currentUser]
 [queryImage getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {

 if (error) {
        NSLog(@"ERROR");
    } else {
        PFFile *file = [object objectForKey:@"imageFile"];

        self.userThumbnail.file = file;

        [self.userThumbnail loadInBackground];
    }
}];

查询版本

 PFQuery *queryImage = [PFUser query];
 [queryImage whereKey:@"imageFile" equalTo:self.currentUser];

 [queryImage getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {

     if (error) {
            NSLog(@"ERROR");
        } else {
            PFFile *file = [object objectForKey:@"imageFile"];

            self.userThumbnail.file = file;

            [self.userThumbnail loadInBackground];
        }
    }];

Answer 1

这一行：

[queryImage whereKey:@"imageFile" equalTo:self.currentUser];

看起来像个错误。它说，“找到其imageFile列（可能是PFImage）等于当前用户对象的用户”。那将永远不会成真。

尝试将寻找用户的逻辑与处理imageFile分开。换一种说法。首先得到一个用户：

PFQuery *queryUser = [PFQuery queryWithClassName:@"User"];
[queryUser whereKey:@"username" equalTo:@"some-user-name"];
[queryUser getFirstObjectInBackgroundWithBlock:^(PFObject *user, NSError *error) {}];

// or maybe instead of username==, get a user with their id ... 
[queryUser getObjectInBackgroundWithId:@"some-user-id" block:^(PFObject *user, NSError *error) {}];

现在，在查询用户的完成块内，执行文件逻辑：

[queryUser getFirstObjectInBackgroundWithBlock:^(PFObject *user, NSError *error) {

    PFFile *userImageFile = user[@"imageFile"];
    [userImageFile getDataInBackgroundWithBlock:^(NSData *imageData, NSError *error) {
        if (!error) {
            UIImage *image = [UIImage imageWithData:imageData];
            // this is a regular UIImage now, put it in your UI
            self.someUIImageView.image = image;
        }
    }];
}];

使用Parse从预定义的User类查询PFFile

1 个答案: