PFImageView 内存问题答案

【问题标题】：PFImageView Memory ProblemsPFImageView 内存问题
【发布时间】：2015-03-17 21:31:11
【问题描述】：

PFImages 的自定义集合视图占用过多内存时遇到问题。在 Parse 中，我只有 7 个对象，但在加载集合视图时内存达到了 1.1 GB。此外，离开视图时内存不会释放。

这是我的代码

自定义单元格

- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];

    if (self) {
        [self setup];
        }
    return self;
} 
- (id)initWithCoder:(NSCoder *)anotherDecoder {
    self = [super initWithCoder:anotherDecoder];

    if (self) {
        [self setup];
    }
    return self;
}

- (void)setup {
    self.pictureImageView = [[PFImageView alloc]init];
    self.pictureImageView.frame = CGRectMake(0, 0, self.pictureView.frame.size.width, self.pictureView.frame.size.height);

    [self.contentView addSubview:pictureImageView];
}

收藏查看代码

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
PicturesCollectionViewCell *cell = (PicturesCollectionViewCell *) [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];

    tempObject =  [picturesArray objectAtIndex:indexPath.row];

    PFFile *file = [tempObject objectForKey:@"thumbnail"];
    cell.pictureImageView.file = file;

    cell.pictureImageView.image = [UIImage imageNamed: @"LOADING.png"];
    [cell.pictureImageView loadInBackground];

    cell.pictureImageView.contentMode = UIViewContentModeScaleAspectFill;

    cell.titleLabel.text = [tempObject objectForKey:@"title"];

    NSLog(@"Image: %@, File: %@, at index: %li", cell.pictureImageView.image, cell.pictureImageView.file, indexPath.row);

    return cell;
}

【问题讨论】：

PFImageView 有开源代码，我认为他们在那里使用 NSCache 会在内存警告时自行清除。

标签： ios objective-c memory parse-platform uicollectionview

【解决方案1】：

在这种情况下解析很糟糕......当代码收到内存警告时会触发清除，这有时会有所帮助：

 - (void)removeCacheFiles {

      [PFQuery clearAllCachedResults];

      NSString *cacheDir = [NSSearchPathForDirectoriesInDomains(
          NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
      NSString *nsurlDir =
          [[NSString alloc] initWithFormat:@"%@/YOUR_BUNDLE_ID", cacheDir];
      NSFileManager *manager = [NSFileManager defaultManager];

      // grab all the files in the documents dir
      NSArray *allFiles = [manager contentsOfDirectoryAtPath:nsurlDir error:nil];

      // filter the array for only sqlite files
      NSPredicate *fltr = [NSPredicate predicateWithFormat:@"self ENDSWITH '.db'"];
      NSArray *dbFiles = [allFiles filteredArrayUsingPredicate:fltr];

      // use fast enumeration to iterate the array and delete the files
      for (NSString *dbFile in dbFiles) {
        NSError *error = nil;
        [manager removeItemAtPath:[nsurlDir stringByAppendingPathComponent:dbFile]
                            error:&error];
        if (error != nil) {
          NSLog(@"Error:%@", [error description]);
        } else {
          NSLog(@"DB FILE Cleared: %@", dbFile);
        }
      }
    }

【讨论】：