Question

如果数据库已经在数据库中显示图像但是不会显示来自Web服务的图像，我如何检查带有数据库的Web服务

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{

 BookCell *bookcell = [collectionView dequeueReusableCellWithReuseIdentifier:@"ReuseCell" forIndexPath:indexPath];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        NSURL *imageURL = [NSURL URLWithString:[[bookList objectAtIndex:indexPath.item]coverURL]];
        NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
        UIImage *image = [UIImage imageWithData:imageData];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *path = [paths objectAtIndex:0];
        NSString *bookPath2 = [NSString stringWithFormat:@"%@/assets/book/%@/cover.png",path,bookPath];
        NSLog(@"bookpath2 = %@",bookPath2);


        dispatch_async(dispatch_get_main_queue(), ^{

            if ([db isDownloaded:bookName bookVersion:[bookVersion floatValue]]) {

            [bookcell.bookCover  setImage:image];
            [bookcell.bookCover setAlpha:1.0f];
//  or this [bookcell.bookCover setImage:[UIImage imageWithContentsOfFile:bookPath2]];

            }
            else{
                [bookcell.bookCover  setImage:image];
                [bookcell.bookCover setAlpha:0.5f];
                [bookcell.bookDetailLabel setHidden:NO];
                [bookcell.bookDetailLabel setAlpha:1.0f];    
            }

        });
    });

    return bookcell;

}

请告诉我。请帮帮我。

Answer 1

我试试这对我有用，谢谢！任何想法

 if (bookPath2 = [NSString stringWithFormat:@"%@/assets/book/%@/cover.png",path],[[bookList objectAtIndex:indexPath.item] bookPath] && bookPath2 != [NSString stringWithFormat:@"%@/assets/book/(null)/cover.png",path]) {
            NSLog(@"++++++++++++++++++++++");
          bookcell.bookCover.image = [UIImage imageWithContentsOfFile:bookPath2];

            if (checkversion < checkNewversion) {
                bookcell.bookDetailLabel.text = @"Update";
                 bookcell.bookDetailLabel.hidden = NO;
            }                else
            {
                 bookcell.bookDetailLabel.hidden = YES;

            }
        }

        else  {
            bookcell.bookCover.image = nil;
         NSLog(@"-------------------------");
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

            NSURL *imageURL = [NSURL URLWithString:[[bookList objectAtIndex:indexPath.item]coverURL]];
            NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
            UIImage *image = [UIImage imageWithData:imageData];

               dispatch_async(dispatch_get_main_queue(), ^{

                   bookcell.bookDetailLabel.text = @"New";
                   bookcell.bookCover.image = [UIImage imageWithData:imageData];
                   bookcell.bookCover.alpha = 0.5f;
                   bookcell.bookDetailLabel.hidden = NO;


            });
        });

        }
        return bookcell;

Collectionview呼叫图像与数据库

1 个答案: