アプリを開発しています。バックグラウンドでデータをロードし、UITableView を使用してデータを表示する必要があります。
バックグラウンドでデータをロードするいくつかのコードを次に示します。
- (void)loadRelatedItems
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
for (NSString *mediaType in allMediaTypes)
{
[self performSelector:@selector(loadRelatedItems:) withObject:mediaType];
}
NSString *notificationName = [CommonFunction allRelatedItemsLoadedNotificationName];
[[NSNotificationCenter defaultCenter] postNotificationName:notificationName object:self userInfo:nil];
[pool release];
}
- (void)loadRelatedItems:(NSString *)mediaType
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
for (NSString *keyword in _keywords)
{
NSURL *URL = [NSURL URLWithString:[NSString stringWithFormat:@"%@&mediaType=%@&keyword=%@", API, mediaType, keyword]];
NSMutableArray *items = [CommonFunctions arrayFromURL:URL];
if ([items count] == 0) continue;
NSString *notificationName = [CommonFunction partialRelatedItemsLoadedNotificationName];
NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:items, @"items", mediaType, @"mediaType", nil];
[[NSNotificationCenter defaultCenter] postNotificationName:notificationName object:self userInfo:dic];
}
[pool release];
}
UITableView でデータを表示する:
- (void)didFinishLoadPartialRelatedItems:(id)sender
{
NSDictionary *dic = [sender userInfo];
NSString *mediaTypeString = [dic objectForKey:@"mediaType"];
NSMutableArray *items = [dic objectForKey:@"items"];
dispatch_async(dispatch_get_main_queue(), ^{
if ([_relatedItems count] == 0)
{
[_relatedItems setObject:items forKey:mediaTypeString];
[_tableView reloadData];
}
else
{
NSMutableArray *mediaTypeItems = [_relatedItems objectForKey:mediaTypeString];
if (mediaTypeItems)
{
// section exist
NSInteger section =[[[_relatedItems allKeys] sortedArrayUsingSelector:@selector(mediaTypeCompare:)] indexOfObject:mediaTypeString];
NSMutableArray *indexPaths = [NSMutableArray array];
for (NSMutableDictionary *item in items)
{
[mediaTypeItems addObject:item];
NSInteger newRow = [mediaTypeItems indexOfObject:item];
NSIndexPath *newIndexPath = [NSIndexPath indexPathForRow:newRow inSection:section];
[indexPaths addObject:newIndexPath];
}
[_tableView beginUpdates];
[_tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationNone];
[_tableView endUpdates];
}
else
{
// new section
[_relatedItems setObject:items forKey:mediaTypeString];
NSInteger section =[[[_relatedItems allKeys] sortedArrayUsingSelector:@selector(mediaTypeCompare:)] indexOfObject:mediaTypeString];
NSIndexSet *indexSet = [NSIndexSet indexSetWithIndex:section];
[_tableView beginUpdates];
[_tableView insertSections:indexSet withRowAnimation:UITableViewRowAnimationNone];
[_tableView endUpdates];
}
}
});
}
#pragma mark -
#pragma mark Table Data Source Methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
if ([_relatedItems count] == 0) {
return 1;
} else {
return [_relatedItems count];
}
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
NSArray *allTitles = [[_relatedItems allKeys] sortedArrayUsingSelector:@selector(mediaTypeCompare:)];
NSString *title = [allTitles objectAtIndex:section];
NSDictionary *allMediaTypeDisplayNames = [CommonFunction allMediaTypeDisplayNames];
return [allMediaTypeDisplayNames objectForKey:title];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if ([_relatedItems count] == 0) {
return 0;
}
NSArray *allTitles = [[_relatedItems allKeys] sortedArrayUsingSelector:@selector(mediaTypeCompare:)];
NSString *title = [allTitles objectAtIndex:section];
NSInteger rowsCount = [[_relatedItems objectForKey:title] count];
return rowsCount;
}
時々うまく動作することに非常に混乱していますが、メッセージでクラッシュすることもありました：
*** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-1912.3/UITableView.m:1030
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of sections. The number of sections contained in the table view after the update (0) must be equal to the number of sections contained in the table view before the update (2), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted).
どうしたの？助けてください。