我刚刚在应用程序中创建了一个
如何使页面滑动更加流畅?
我的代码:前16张图片是预设的,其余来自文档目录中的子目录。
UICollectionView
,通过这个功能用户可以将手机中的图片添加到相册中。我将这些图片保存在文档目录的子目录中,所以用户可以随时添加或删除图片。但是,当我在集合视图中上下滚动时,会有很大的延迟。如何使页面滑动更加流畅?
我的代码:前16张图片是预设的,其余来自文档目录中的子目录。
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
CollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Custom" forIndexPath:indexPath];
//Current index number
int index=indexPath.section * noOfSection + indexPath.row;
//Check if its the preset photos
if(index<16){
NSString *name=[recipePhotos objectAtIndex:indexPath.section * noOfSection + indexPath.row];
cell.imageView.image=[UIImage imageNamed:name];
}
//not preset photos, so retrieve the photos the user added
else {
NSData *data= [NSData dataWithContentsOfFile:[recipePhotos objectAtIndex:index]];
UIImage *theImage=[UIImage imageWithData:data];
cell.imageView.image=theImage;
data=nil;
}
return cell;
}
时间分析器给了我以下内容
Running Time Self Symbol Name
568.0ms 63.1% 0.0 Main Thread 0x4048
320.0ms 35.5% 0.0 _pthread_start 0x405e
320.0ms 35.5% 0.0 thread_start
320.0ms 35.5% 0.0 _pthread_start
320.0ms 35.5% 0.0 0x1084be960
310.0ms 34.4% 1.0 0x1084be6f0
7.0ms 0.7% 0.0 mach_msg
2.0ms 0.2% 2.0 objc_msgSend
1.0ms 0.1% 1.0 -[NSAutoreleasePool release]
4.0ms 0.4% 0.0 _dispatch_mgr_thread 0x4052
4.0ms 0.4% 0.0 _dispatch_mgr_thread
4.0ms 0.4% 0.0 _dispatch_mgr_invoke
4.0ms 0.4% 4.0 kevent
3.0ms 0.3% 0.0 _dispatch_worker_thread2 0x62b24
3.0ms 0.3% 1.0 start_wqthread
3.0ms 0.3% 0.0 _dispatch_worker_thread2 0x62a84
3.0ms 0.3% 0.0 start_wqthread
3.0ms 0.3% 0.0 _pthread_wqthread
3.0ms 0.3% 0.0 _dispatch_worker_thread2
3.0ms 0.3% 0.0 _dispatch_queue_invoke
3.0ms 0.3% 0.0 _dispatch_queue_drain
3.0ms 0.3% 0.0 _dispatch_client_callout
2.0ms 0.2% 0.0 my_io_execute_passive_block
1.0ms 0.1% 0.0 __86-[NSPersistentUIManager writePublicPlistWithOpenWindowIDs:optionallyWaitingUntilDone:]_block_invoke_0835
1.0ms 0.1% 0.0 -[NSPersistentUIManager writePublicPlistData:]
1.0ms 0.1% 0.0 -[NSURL(NSURLPathUtilities) URLByAppendingPathComponent:]
1.0ms 0.1% 0.0 -[NSURL getResourceValue:forKey:error:]
1.0ms 0.1% 0.0 CFURLCopyResourcePropertyForKey
1.0ms 0.1% 0.0 __block_global_2
1.0ms 0.1% 0.0 -[NSPersistentUIManager writeRecords:withWindowInfos:flushingStaleData:]
1.0ms 0.1% 0.0 _dispatch_call_block_and_release
1.0ms 0.1% 0.0 0x1084b8580
1.0ms 0.1% 0.0 mach_msg_send
1.0ms 0.1% 0.0 mach_msg
1.0ms 0.1% 1.0 mach_msg_trap
1.0ms 0.1% 0.0 _pthread_struct_init 0x62a83
1.0ms 0.1% 0.0 start_wqthread
1.0ms 0.1% 0.0 _pthread_wqthread
1.0ms 0.1% 1.0 _pthread_struct_init
1.0ms 0.1% 0.0 start_wqthread 0x62a7f
CollectionCell
中进行过任何自定义绘制吗? - rog//注册nib UINib *nib = [UINib nibWithNibName:@"CollectionCell" bundle:nil]; [_collectionView registerNib:nib forCellWithReuseIdentifier:@"Custom"];
- Phil Scarf