iphone - 下载文件时如何更新 UICollectionViewCell 子类中的进度条

Question

我要疯了，我正在尝试更新 UICollectionViewCelll 的进度条，当我下载一个文件时，我已经尝试了一切，一切一切，这是我最后一次尝试，我已经创建UICollectionViewCell 的子类，与 xib 文件相连:

#import <UIKit/UIKit.h>

@interface DocumentCell : UICollectionViewCell

@property (weak, nonatomic) IBOutlet UIImageView *documentImage;
@property (weak, nonatomic) IBOutlet UIProgressView *downloadBar;

- (void)downloadDocumentWithUrl:(NSURLRequest *)requestUrl;

@end 

- (void)downloadDocumentWithUrl:(NSURLRequest *)requestUrl
{
.....
AFDownloadRequestOperation *request = [[AFDownloadRequestOperation alloc] initWithRequest:requestUrl targetPath:zipDownloadPath shouldResume:YES];

[request setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"Successfully downloaded file to %@", zipDownloadPath);

 } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);

    }];

[request setProgressiveDownloadProgressBlock:^(NSInteger bytesRead, long long totalBytesRead, long long totalBytesExpected, long long totalBytesReadForFile, long long totalBytesExpectedToReadForFile) {

        NSLog(@"%f",totalBytesReadForFile/(float)totalBytesExpectedToReadForFile);
        [self performSelectorOnMainThread:@selector(updateBar:) withObject:[NSNumber numberWithFloat:(totalBytesReadForFile/(float)totalBytesExpectedToReadForFile)] waitUntilDone:YES];
    }];

    [downloadQueue addOperation:request];
}

- (void)updateBar:(NSNumber *)floatNumber
{
    [self.downloadBar setProgress:[floatNumber floatValue]];
}

NSLog setProgressiveDownloadProgressBlock 完美运行，我可以看到我下载的所有字节，但进度条不会自行更新，始终保持为零...我不明白该怎么做...这就是我的方式显示单元格，并调用下载方法:

- (void)startDownload:(NSString *)downloadUrl
{
    //DocumentCell *cell = (DocumentCell *)[self.collectionView cellForItemAtIndexPath:self.downloadPath]; i have tried also in this way
     DocumentCell *cell = (DocumentCell *)[self.collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:self.downloadPath];

[cell downloadDocumentWithUrl:requestUrl];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    UINib *cellNib = [UINib nibWithNibName:@"DocumentCell" bundle:nil];
    [self.collectionView registerNib:cellNib forCellWithReuseIdentifier:CellIdentifier];
    ...
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    DocumentCell *cell = (DocumentCell *)[collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
 cell.documentImage.....etc

return cell;
}

谁能帮帮我？下载文件的方法被调用，下载的字节的nslog工作，进度条不...请帮我更新这个进度条...

Answer 1

试试这个:

[self performSelectorOnMainThread:@selector(updateBar:) withObject:[NSNumber numberWithFloat:((float)totalBytesReadForFile/(float)totalBytesExpectedToReadForFile)] waitUntilDone:YES];