NSPredicate 不过滤 UITableView？

Question

由于某种原因，NSPredicate 没有过滤我的 UITableView（它应该通过 UIPickerView 中的选择过滤我的 TableView）。用户做出他们的pickerview选择，按下GO按钮（segue从Pickerview连接到Table View控制器）。

知道为什么它不起作用吗？请参阅下面的代码。

ViewController.m（表视图控制器）

- (int)numberOfSectionsInTableView: (UITableView *)tableview

{

    return 1;

}

- (int)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    if (tableView == self.searchDisplayController.searchResultsTableView) {
        return [searchResults count];




    } else {
        return [Strains count];

    }



}



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{


    static NSString *strainTableIdentifier = @"StrainTableCell";

    StrainTableCell *cell = (StrainTableCell *)[tableView dequeueReusableCellWithIdentifier:strainTableIdentifier];
    if (cell == nil) 


        cell = [[StrainTableCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:strainTableIdentifier];



        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"StrainTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];

    if (tableView == self.searchDisplayController.searchResultsTableView) {
       NSLog(@"Using the search results");

        cell.titleLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Title"];
        cell.descriptionLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Description"];
        cell.ratingLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Rating"];
        cell.ailmentLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Ailment"];
        cell.actionLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Action"];
        cell.ingestLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Ingestion"];

        NSLog(@"%@", searchResults);


    } else {
        NSLog(@"Using the FULL LIST!!");
        cell.titleLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Title"];
         cell.descriptionLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Description"];
         cell.ratingLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Rating"];
        cell.ailmentLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Ailment"];
        cell.actionLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Action"];
        cell.ingestLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Ingestion"];

    }


return cell;

}




- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
    NSPredicate *resultPredicate = [NSPredicate 
                                    predicateWithFormat:@"Title contains[cd] %@",
                                    searchText];

    searchResults = [Strains filteredArrayUsingPredicate:resultPredicate];


}





-(BOOL)searchDisplayController:(UISearchDisplayController *)controller
shouldReloadTableForSearchString:(NSString *)searchString
{
    [self filterContentForSearchText:searchString
                               scope:[[self.searchDisplayController.searchBar scopeButtonTitles]
                                      objectAtIndex:[self.searchDisplayController.searchBar
                                                     selectedScopeButtonIndex]]];

    return YES;
}



- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {


    StrainDetailViewController *detailViewController = [[StrainDetailViewController alloc] initWithNibName:@"StrainDetailViewController" bundle:nil]; if ([searchResults count]) {

        detailViewController.title = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Title"];
        detailViewController.strainDetail = [searchResults objectAtIndex:indexPath.row];

    } else {

        detailViewController.title = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Title"];
        detailViewController.strainDetail = [Strains objectAtIndex:indexPath.row];
        NSLog(@"%@", Strains);
    }

    [self.navigationController pushViewController:detailViewController animated:YES];



    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)PickerViewControllerDidFinish:(PickerViewController *)viewController {
  [self.navigationController popViewControllerAnimated:YES];

}

PickerViewController.h

@protocol PickerViewControllerDelegate;

@interface PickerViewController : UIViewController {


    UIPickerView *pickerView;

    NSMutableArray *array1;
    NSMutableArray *array2;
    NSMutableArray *array3;



    NSArray *Strains;
    NSArray *searchResults;

    NSMutableData *data;



}

- (IBAction)buttonpressed:(UIButton *)sender;

@property (nonatomic, weak) id<PickerViewControllerDelegate> delegate;

@property (nonatomic, retain) IBOutlet UIPickerView *pickerView;

- (void)populateArray1;
- (void)populateArray2;
- (void)populateArray3;




@end

@protocol PickerViewControllerDelegate <NSObject>

- (void)PickerViewControllerDidFinish:(PickerViewController*)viewController;

@end

PickerViewController.m

  #pragma mark -
#pragma mark picker view methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;
{
    return 3;
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    if (component == 0)
    {
        NSLog(@"you selected %@", [array1 objectAtIndex:row]);

    }

    if (component == 1)
    {
        NSLog(@"you selected %@", [array2 objectAtIndex:row]);

    }


    if (component == 2)
    {
        NSLog(@"you selected %@", [array3 objectAtIndex:row]);

    }




}




- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;
{




    if (component == 0)
    {
        return [array1 count];
    }

    if (component == 1)
    {
        return [array2 count];
    }


    if (component == 2)
    {
        return [array3 count];
    }

    else
    {
        return [array1 count];
    }
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;
{

    if (component == 0)
    {
        return [array1 objectAtIndex:row];
    }

    if (component == 1)
    {
        return [array2 objectAtIndex:row];
    }

    if (component == 2)
    {
        return [array3 objectAtIndex:row];
    }

    else
    {
        return [array2 objectAtIndex:row];
    }
}



- (void)populateArray1
{
    array1 = [[NSMutableArray alloc] init];

    [array1 addObject:@"Arthritis"];
    [array1 addObject:@"Cancer"];
    [array1 addObject:@"HIV"];
    [array1 addObject:@"Migraines"];
    [array1 addObject:@"Insomnia"];

}

- (void)populateArray2
{
    array2 = [[NSMutableArray alloc] init];

    [array2 addObject:@"Nausea"];
    [array2 addObject:@"Pain"];
    [array2 addObject:@"Appetite"];
    [array2 addObject:@"Fever"];
    [array2 addObject:@"Exhaustion"];

}

- (void)populateArray3
{
    array3 = [[NSMutableArray alloc] init];

    [array3 addObject:@"Oil"];
    [array3 addObject:@"Plant"];
    [array3 addObject:@"Edible"];
    [array3 addObject:@"Powder"];


}



- (IBAction)buttonpressed:(UIButton *)sender {

        NSLog(@"Button Pushed!");

}



- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Make sure your segue name in storyboard is the same as this line
    if ([[segue identifier] isEqualToString:@"pickerGo"])
    {
        // Get reference to the destination view controller
        ViewController *strainTableView = [(UINavigationController *)[segue destinationViewController] topViewController];

        NSPredicate *ailmentPredicate = [NSPredicate predicateWithFormat:@"Ailment contains[cd] %@", [pickerView selectedRowInComponent:0]];

        NSPredicate *actionPredicate = [NSPredicate predicateWithFormat:@"Action contains[cd] %@", [pickerView selectedRowInComponent:1]];

        NSPredicate *ingestPredicate = [NSPredicate predicateWithFormat:@"Ingestion contains[cd] %@", [pickerView selectedRowInComponent:2]];


        NSCompoundPredicate *resultPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:[NSArray arrayWithObjects: ailmentPredicate,actionPredicate,ingestPredicate, nil]];

        searchResults = [Strains filteredArrayUsingPredicate:resultPredicate];

        // Pass any objects to the view controller here, like...
        [strainTableView setSearchResults: searchResults];
    }
}

Answer 1

非常令人费解，您的代码实际上对我来说似乎没问题。我会在searchResults = [Strains filteredArrayUsingPredicate:resultPredicate]; 行被触发后立即从 NSLoging searchResults 开始，以防表视图代表中发生有趣的事情。

您还应该查看免费的 Sensible TableView 框架，因为它为您的数据提供了自动搜索和过滤功能。应该可以为您节省大量时间。

Answer 2

您的 Strains 数组似乎包含字典。所以你应该决定你想要过滤什么键，例如标题键，而不是使用SELF：

NSPredicate *resultPredicate = [NSPredicate 
                                predicateWithFormat:@"Title contains[cd] %@",
                                searchText];

从pickerViewController，你需要回到tableViewController。您可以使用委托。并尝试在表格视图控制器中创建一个单独的函数来过滤包含谓词的内容：

- (void)filterContentForPicker:(NSString*)searchText
{
    NSPredicate *resultPredicate = [NSPredicate
                                    predicateWithFormat:@"Title contains[cd] %@",
                                    searchText];

    searchResults = [Strains filteredArrayUsingPredicate:resultPredicate];
    [self.tableView reloadData]
}