ios - 带有核心数据的慢速 UISearchDisplayController

Question

我有一个 TableViewController，使用 NSFetchedResultsController 显示核心数据中的大约 40,000 行。

我使用 UISearchDisplayController(支持 IOS 7)实现了实时搜索。它工作正常，但在搜索时在键盘上打字非常慢...

如果有人能指出正确的方向并告诉我哪里可能出错，我将不胜感激。

这是我的 TableViewController 中的 UISearchResultsUpdating 部分

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
    ItemSearchScope scopeKey = controller.searchBar.selectedScopeButtonIndex;
    [self searchForText:searchString scope:scopeKey];
    return YES;
}

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchScope:(NSInteger)searchOption
{
    NSString *searchString = controller.searchBar.text;
    [self searchForText:searchString scope:searchOption];
    return YES;
}

- (void)searchForText:(NSString *)searchText scope:(ItemSearchScope)scopeOption
{
    if (self.managedObjectContext)
{
    NSString *predicateFormat = @"%K CONTAINS[cd] %@";

    NSString *searchAttribute1 = @"attribute1";
    NSString *searchAttribute2 = @"attribute2";
    NSString *searchAttribute3 = @"attribute3";

    if (scopeOption == searchScopeDebut) {
        predicateFormat = @"%K BEGINSWITH[cd] %@";
    }

    if (scopeOption == searchScopeFin) {
        predicateFormat = @"%K ENDSWITH[cd] %@";
    }

    NSPredicate *p1 = [NSPredicate predicateWithFormat:predicateFormat, searchAttribute1, searchText];
    NSPredicate *p2 = [NSPredicate predicateWithFormat:predicateFormat, searchAttribute2, searchText];
    NSPredicate *p3 = [NSPredicate predicateWithFormat:predicateFormat, searchAttribute3, searchText];

    NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:@[p1, p2, p3]];

    [self.searchFetchRequest setPredicate:predicate];

    NSError *error = nil;
    self.filteredList = [self.managedObjectContext executeFetchRequest:self.searchFetchRequest error:&error];
    if (error)
    {
        NSLog(@"searchFetchRequest failed: %@",[error localizedDescription]);
    }
}

Answer 1

我最终使用 NSTimer 来延迟 shouldReloadTableForSearchString 方法。 searchTimerPopped 选择器仅在用户停止键入键盘 2 秒时触发。

@property (nonatomic, retain) NSTimer *searchTimer;

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
    if (self.searchTimer) {
        [self.searchTimer invalidate];
        self.searchTimer = nil;
    }
    self.searchTimer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(searchTimerPopped:) userInfo:searchString repeats:FALSE];
    return NO;
}

- (void)searchTimerPopped:(NSTimer *)timer {
    NSString *searchString = [timer userInfo];
    ItemSearchScope scopeKey = self.searchDisplayController.searchBar.selectedScopeButtonIndex;
    [self searchForText:searchString scope:scopeKey];
    [self.searchDisplayController.searchResultsTableView reloadData];
}