如何在表或集合视图中实现无尽的加载？
我正在构build一篇文章阅读应用程序。 我从JSON链接获取数据，如文章图像和标题在uitableview中。
我无法在uitableview中实现分页，假设我的JSON链接是www.example.com＆page = 1包含10个文章，每次1-10个。
当我在像www.example.com＆page = 2这样的JSON链接中进行连接以获得11-20条文章列表。
我无法实现如何加载滚动的uitableview中的数据，并增加数据行的数量。
这是我的代码：
int *x=1; int *inc=10; @interface ysTableViewController () { Reachability *internetReachable; } @end @implementation ysTableViewController - (id)initWithStyle:(UITableViewStyle)style { self = [super initWithStyle:style]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad { [super viewDidLoad]; [self checkInternetConnection]; UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(20,10,0,20)]; titleLabel.textColor = [UIColor blackColor]; titleLabel.backgroundColor = [UIColor clearColor]; titleLabel.text = @"Story"; [self.navigationItem setTitleView:titleLabel]; } - (void)scrollViewDidScroll:(UIScrollView *)aScrollView { CGPoint offset = aScrollView.contentOffset; CGRect bounds = aScrollView.bounds; CGSize size = aScrollView.contentSize; UIEdgeInsets inset = aScrollView.contentInset; float y = offset.y + bounds.size.height - inset.bottom; float h = size.height; float reload_distance = 10; if(y > h + reload_distance) { NSLog(@"load more rows"); inc=inc+10; BOOL myBool = [self isNetworkAvailable]; if (myBool) { @try { // for table cell seperator line color self.tableView.separatorColor = [UIColor colorWithRed:190/255.0 green:190/255.0 blue:190/255.0 alpha:1.0]; // for displaying the previous screen lable with back button in details view controller UIBarButtonItem *backbutton1 = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStyleBordered target:nil action:nil]; [[self navigationItem] setBackBarButtonItem:backbutton1]; _Title1 = [[NSMutableArray alloc] init]; _Author1 = [[NSMutableArray alloc] init]; _Images1 = [[NSMutableArray alloc] init]; _Details1 = [[NSMutableArray alloc] init]; _link1 = [[NSMutableArray alloc] init]; _Date1 = [[NSMutableArray alloc] init]; NSString *urlString=[NSString stringWithFormat:@“www.example.com&page=%d",x]; NSLog(@"xxxxx===%d",x); NSURL *newUrl=[NSURL URLWithString:urlString]; NSData* data = [NSData dataWithContentsOfURL:newUrl]; NSArray *ys_avatars = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil]; x++; if(ys_avatars){ for (int j=0;j<ys_avatars.count;j++) { [_Title1 addObject:ys_avatars[j][@"title"]]; [_Author1 addObject: ys_avatars[j][@"author"]]; [_Images1 addObject: ys_avatars[j][@"featured_img"]]; [_Details1 addObject:ys_avatars[j][@"content"]]; [_link1 addObject:ys_avatars[j][@"permalink"]]; NSString *newStr=[ys_avatars[j][@"date"] substringToIndex:[ys_avatars[j][@"date"] length]-3]; [_Date1 addObject:newStr]; } } else { NSLog(@"asd"); } } @catch (NSException *exception) { } } } } - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { // Return the number of sections. return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { // Return the number of rows in the section. return inc; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *Cellidentifier1 = @"ysTableViewCell"; ysTableViewCell *cell1 = [tableView dequeueReusableCellWithIdentifier:Cellidentifier1 forIndexPath:indexPath]; // Configure the cell... long row = [indexPath row]; cell1.TitleLabel1.text = _Title1[row]; cell1.AuthorLabel1.text = _Author1[row]; NSString *yourStoryUrl = [_Images1[indexPath.row] stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]; if(yourStoryUrl) { NSArray *subStringsUrl = [yourStoryUrl componentsSeparatedByString:@"/"]; NSString *stripedName = [subStringsUrl lastObject]; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; //Local stored image file path NSString* filePath =[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@",stripedName]]; if(filePath) { UIImage *image = [UIImage imageWithContentsOfFile:filePath]; if(image) { // Now the image will have been loaded and decoded and is ready to rock for the main thread ysTableViewCell *updateCell =(id)[tableView cellForRowAtIndexPath:indexPath]; if(updateCell) updateCell.ThumbImage1.image=image; cell1.ThumbImage1.image=image; } else { dispatch_queue_t taskQ = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); dispatch_async(taskQ, ^{ NSURL *Imageurl = [NSURL URLWithString:yourStoryUrl]; NSData *data = [NSData dataWithContentsOfURL:Imageurl]; UIImage *images1 = [[UIImage alloc] initWithData:data]; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSData *imageData = UIImagePNGRepresentation(images1); //_imagePath =[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png",stripedName]]; // NSLog((@"pre writing to file")); if (![imageData writeToFile:filePath atomically:NO]) { NSLog((@"Failed to cache image data to disk")); } else { NSLog((@"the cachedImagedPath is %@",filePath)); } // Now the image will have been loaded and decoded and is ready to rock for the main thread dispatch_sync(dispatch_get_main_queue(), ^{ ysTableViewCell *updateCell =(id)[tableView cellForRowAtIndexPath:indexPath]; if(updateCell) updateCell.ThumbImage1.image=images1; cell1.ThumbImage1.image=images1; }); }); } } else { dispatch_queue_t taskQ = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); dispatch_async(taskQ, ^{ NSURL *Imageurl = [NSURL URLWithString:yourStoryUrl]; NSData *data = [NSData dataWithContentsOfURL:Imageurl]; UIImage *images1 = [[UIImage alloc] initWithData:data]; // NSString *myString = [Imageurl absoluteString]; // NSLog(@"%@",myString); NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSData *imageData = UIImagePNGRepresentation(images1); _imagePath =[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png",stripedName]]; // NSLog((@"pre writing to file")); if (![imageData writeToFile:_imagePath atomically:NO]) { NSLog((@"Failed to cache image data to disk")); } else { // NSLog((@"the cachedImagedPath is %@",_imagePath)); } // Now the image will have been loaded and decoded and is ready to rock for the main thread dispatch_sync(dispatch_get_main_queue(), ^{ ysTableViewCell *updateCell =(id)[tableView cellForRowAtIndexPath:indexPath]; if(updateCell) updateCell.ThumbImage1.image=images1; cell1.ThumbImage1.image=images1; }); }); } } return cell1; } 这绝非易事。 一般条款你需要看起来像这样的代码
注意这个基本程序的四个非常不同的部分。
我从来没有find这个问题的工作“一般”包解决scheme。
再次，看看这个“四个部分”：他们提供你正在寻找的逻辑！
-(void)forTerm:(NSString *)term doPageAfter:(int)doingThisPage { doingThisPage = doingThisPage + 1; if ( doingThisPage > 20 ) return; // never, ever, ever forget that!! heh. [CLOUD search:term page:doingThisPage then:^(NSArray *thoseTenResults) { self.searchSpinner.hidden = YES; // (step 1) IF IT IS "PAGE 1", we need to re-kick-off the array... if ( doingThisPage == 1 ) CLOUD.searchResultsRA = [[NSMutableArray alloc] init]; // (step 2) go ahead and add on these results if ( doingThisPage == 1 ) { [CLOUD.searchResultsRA addObjectsFromArray:thoseTenResults]; [self.searchDisplay safelyReloadBouncyTable]; } else { [self.searchDisplay.collectionView performBatchUpdates:^ { NSUInteger oldSize = CLOUD.searchResultsRA.count; [CLOUD.searchResultsRA addObjectsFromArray:thoseTenResults]; NSUInteger newSize = CLOUD.searchResultsRA.count; NSMutableArray *arrayWithIndexPaths = [NSMutableArray array]; for (NSUInteger i = oldSize; i < newSize; i++) [arrayWithIndexPaths addObject:[NSIndexPath indexPathForRow:i inSection:0]]; [self.searchDisplay justSignal]; [self.searchDisplay.collectionView insertItemsAtIndexPaths:arrayWithIndexPaths]; } completion:nil]; } // (step 3) indeed if it's the first page, do a drop-in for fun if ( doingThisPage == 1 ) [self.searchDisplay.view dropIn:nil]; // (for a "new search" which is now being displayed, in your UX // there would be some sort of indication of that fact - do it here) // (step 4) IF there WERE results .. try another page! if ( thoseTenResults.count > 0 ) [self forTerm:term doPageAfter:doingThisPage]; // note we are calling this same routine, again!!! } ]; }