MPMediaItemArtwork is null while cover is available in iTunes

问题

The UIImage "image" is always empty ("null") though the cover is shown in the music app by apple. in iOS 7 it works fine, but with iOS 8 I get no cover.

Whats wrong with my code, or what has changed in iOS 8?

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    AlbumCell *cell = [tableView dequeueReusableCellWithIdentifier:@"AlbumCell"];
    MPMediaItemCollection *song = self.songsList[indexPath.row];

    cell.albumName.text = [[song representativeItem] valueForProperty: MPMediaItemPropertyAlbumTitle];

    cell.albumArtist.text = [[song representativeItem] valueForProperty:MPMediaItemPropertyAlbumArtist];


    CGSize artworkImageViewSize = CGSizeMake(100, 100);
    MPMediaItemArtwork *artwork = [song valueForProperty:MPMediaItemPropertyArtwork];
    UIImage *image = [artwork imageWithSize:artworkImageViewSize];

    NSLog(@"-------------------");
    NSLog(@"%@",[[song representativeItem] valueForProperty: MPMediaItemPropertyAlbumTitle]);
    NSLog(@"%@",image);

    if (artwork) {

        cell.cover.image = image;
    }
    else
    {
        cell.cover.image = [UIImage imageNamed:@"nocover.png"];
    }

    return cell;
}

回答1:

As of iOS 8, MPMediaItem's selector imageWithSize:(CGSize)size appears to not guarantee that it will return an image. If no image is returned at the requested size, call it again with the size of the artwork bounds property:

MPMediaItemArtwork *artwork = [self valueForProperty:MPMediaItemPropertyArtwork];
UIImage *image = [artwork imageWithSize:size];
if (image == nil) {
    image = [artwork imageWithSize:artwork.bounds.size];
}

回答2:

i´ve found the problem.

it´s

 CGSize artworkImageViewSize = CGSizeMake(100, 100);

the following works:

 CGSize artworkImageViewSize = CGSizeMake(120, 120);

 CGSize artworkImageViewSize = CGSizeMake(60, 60);

everything that can be divided by 3 works.

回答3:

Your code looks fine. I have the same code for getting artwork and it's working for me on iOS 8. Are you SURE the item actually has artwork? Play that song in the music app - artwork?

来源：https://stackoverflow.com/questions/25998621/mpmediaitemartwork-is-null-while-cover-is-available-in-itunes

标签

ios

null

mpmediaitem

cover

artwork