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我有一個表格視圖控制器,其中我在每個單元格的imageview中顯示應用程序中記錄的視頻的縮略圖。他們有90.5的高度,並沒有什麼特別的。然而,加載這個視圖會增加40 MB到內存,這太多了。我不知道爲什麼會發生這種情況,有人可以提供一些見解嗎?UITableViewCell.imageView給內存警告?
知道縮略圖作爲二進制數據存儲在視頻對象中可能很有用。
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = @"Video Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
self.tableView.rowHeight = 90.5;
cell.imageView.tag = indexPath.row;
Video *video = [self.videoArray objectAtIndex:indexPath.row];
cell.textLabel.text = [self.dateFormatter stringFromDate:video.createdAt];
cell.detailTextLabel.text = video.video_description;
cell.detailTextLabel.text = @"Tap on the thumbnail to add video information!";
cell.imageView.image = [UIImage imageWithData:video.thumbnail];
UIView *highlighted = [[UIView alloc]initWithFrame:cell.bounds];
[highlighted setBackgroundColor:[UIColor colorWithRed:0 green:122.0/255.0 blue:1.0 alpha:1.0]];
cell.selectedBackgroundView = highlighted;
cell.textLabel.highlightedTextColor = [UIColor whiteColor];
cell.detailTextLabel.highlightedTextColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.70];
return cell;
}
這裏是我得到的縮略圖:
- (UIImage *)generateThumbnailAtURL:(NSURL *)URL {
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:URL options:nil];
AVAssetImageGenerator *generate = [[AVAssetImageGenerator alloc] initWithAsset:asset];
//generate.appliesPreferredTrackTransform = YES;
NSError *err = nil;
double halfTime = ((CMTimeGetSeconds(asset.duration))/2);
CMTime time = CMTimeMake(halfTime, 1);
CGImageRef imgRef = [generate copyCGImageAtTime:time actualTime:nil error:&err];
UIImage *thumbnail = [[UIImage alloc] initWithCGImage:imgRef];
CGImageRelease(imgRef);
[thumbnail imageByScalingToSize:CGSizeMake(130,90) contentMode:UIViewContentModeScaleAspectFill];
return [UIImage imageWithData:UIImageJPEGRepresentation(thumbnail, 0.1)];
}
嗯。這是一個高清視頻的快照,但縮小到130x90,然後在0.1的JPGRepresentation,所以它不應該很大..? –
你當時是正確的。我忘了將130x90分配爲新的縮略圖。哎呦。感謝,並與霰彈槍很好的比喻。 –