SearchBar 可点击结果 - 核心数据

Posted 2023-02-27

【中文标题】SearchBar 可点击结果 - 核心数据

【英文标题】：SearchBar clickable results - Core Data

【发布时间】：2014-02-22 16:01:38

【问题描述】：

我是 Xcode 的新手，所以我一直在使用有关如何在我的笔记应用程序中实现 SearchBar 的教程。 SearchBar 从表格视图中检索数据，但是当我单击它时，它不会将我带到页面。我将如何在UIStoryboardSegue 中解决这个问题，记住我对所有这些东西都是新手！提前致谢：3

    #import "DeviceViewController.h"
#import "DeviceDetailViewController.h"
@interface DeviceViewController ()
@property (strong) NSMutableArray *devices;
@end

@implementation DeviceViewController

    NSArray *searchResults;

- (NSManagedObjectContext *)managedObjectContext 
    NSManagedObjectContext *context = nil;
    id delegate = [[UIApplication sharedApplication] delegate];
    if ([delegate performSelector:@selector(managedObjectContext)]) 
        context = [delegate managedObjectContext];
    
    return context;

- (id)initWithStyle:(UITableViewStyle)style

    self = [super initWithStyle:style];
    if (self) 
    
    return self;


- (void)viewDidLoad

    [super viewDidLoad];
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectZero];
    //label.backgroundColor = [UIColor clearColor];
    label.font = [UIFont fontWithName:@"HelveticaNeue-thin" size:28];
    //label.shadowColor = [UIColor colorWithWhite:0.0 alpha:0.5];
    label.textColor = [UIColor blackColor];
    self.navigationItem.titleView = label;
    label.text = @"TapNotes";
    [label sizeToFit];


- (void)viewDidAppear:(BOOL)animated

    [super viewDidAppear:animated];
    // Fetch the devices from persistent data store
    NSManagedObjectContext *managedObjectContext = [self managedObjectContext];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Device"];
    self.devices = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];

    [self.tableView reloadData];


- (void)didReceiveMemoryWarning

    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.


#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

    // Return the number of sections.
    return 1;


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

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

     else 
        return self.devices.count;
    
    //return self.devices.count;
    
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell==nil) 
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier]; 
    NSManagedObject *device = [self.devices objectAtIndex:indexPath.row];
    [cell.textLabel setText:[NSString stringWithFormat:@"%@", [device valueForKey:@"name"]]];
    [cell.detailTextLabel setText:[NSString stringWithFormat:@"%@",[device valueForKey:@"version"]]];
    if (tableView == self.searchDisplayController.searchResultsTableView) 
        device = [searchResults objectAtIndex:indexPath.row];
     else 
        [self.devices objectAtIndex:indexPath.row];
    

   // cell.thumbnailImageView.image = [UIImage imageNamed:recipe.image];

    return cell;

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath

    // Return NO if you do not want the specified item to be editable.
    return YES;



- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath

    NSManagedObjectContext *context = [self managedObjectContext];

    if (editingStyle == UITableViewCellEditingStyleDelete) 
        // Delete object from database
        [context deleteObject:[self.devices objectAtIndex:indexPath.row]];

        NSError *error = nil;
        if (![context save:&error]) 
            NSLog(@"Can't Delete! %@ %@", error, [error localizedDescription]);
            return;
        

        // Remove device from table view
        [self.devices removeObjectAtIndex:indexPath.row];
        [self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
    


/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath

    if (editingStyle == UITableViewCellEditingStyleDelete) 
        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
       
    else if (editingStyle == UITableViewCellEditingStyleInsert) 
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
       

*/

/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath


*/

/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath

    // Return NO if you do not want the item to be re-orderable.
    return YES;

*/
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

    if ([[segue identifier] isEqualToString:@"UpdateDevice"]) 
        NSManagedObject *selectedDevice = [self.devices objectAtIndex:[[self.tableView indexPathForSelectedRow] row]];
         NSIndexPath *indexPath = nil;
         //Device *device = nil;
        if (self.searchDisplayController.active) 
            indexPath = [self.searchDisplayController.searchResultsTableView indexPathForSelectedRow];
            _devices = [searchResults objectAtIndex:indexPath.row];
         else 
            indexPath = [self.tableView indexPathForSelectedRow];
            _devices = [_devices objectAtIndex:indexPath.row];
        
        DeviceDetailViewController *destViewController = segue.destinationViewController;
        destViewController.device = selectedDevice;
    

- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope

    NSPredicate *resultPredicate = [NSPredicate predicateWithFormat:@"name contains[c] %@", searchText];
    searchResults = [_devices filteredArrayUsingPredicate:resultPredicate];

-(BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString

    [self filterContentForSearchText:searchString
                               scope:[[self.searchDisplayController.searchBar scopeButtonTitles]
                                      objectAtIndex:[self.searchDisplayController.searchBar
                                                     selectedScopeButtonIndex]]];

    return YES;

@end

【参考方案1】：

UIStoryboardSegue 只能通过故事板连接。由于您通过 UISearchDisplayController 呈现搜索数据，因此您需要实现 tableView:didSelectRowAtIndexPath:。在这种方法中，您需要确保仅在从连接到 UISearchDisplayController 的 tableview 接收事件时才执行推送到新视图控制器。在这种方法中，我建议您使用 performSegueWithIdentifier: 并手动连接一个 segue你的故事板。有关如何创建手动转场的更多详细信息，请参阅此答案：https://***.com/a/17012857/1049509

【讨论】：

实际上解决方案比这更简单！我在[self.tableView dequeueReusableCellWithIdentifier 代码行中添加了self.。现在它运行完美。非常感谢布拉赫