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Core Data淺談係列之五 : 在UITableView中展示

在邏輯上(表關係)將Team和Player關聯起來後,我們將其展現到UI視圖上。

首先,為App添加導航欄:
@interface AppDelegate : UIResponder <UIApplicationDelegate >

@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) UINavigationController *navController;
@property (strong, nonatomic) ViewController *viewController;

@end


@implementation AppDelegate

- (void)dealloc
{
    [_window release];
    [_navController release];
    [_viewController release];
    [super dealloc];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    self.navController = [[[UINavigationController alloc] initWithRootViewController:self.viewController] autorelease];
    self.window.rootViewController = self.navController;
    [self.window makeKeyAndVisible];
    return YES;
}
然後在ViewController上添加一個UITableView,布局好並實現如下相應的代理函數:
#pragma mark - 
#pragma mark - UITableView DataSource

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.teamArray count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"TeamTableViewCellIdentifier";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    if (nil == cell) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier] autorelease];
    }
    
    Team *teamObject = [self.teamArray objectAtIndex:indexPath.row];
    UIImage *nbaImage = [UIImage imageNamed:@"nba@2x.jpg"];
    cell.imageView.image = nbaImage;
    cell.imageView.backgroundColor = [UIColorredColor];
    cell.textLabel.text = teamObject.name;
    cell.detailTextLabel.text = teamObject.city;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    
    return cell;
}

#pragma mark - 
#pragma mark - UITableView Delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
    
    Team *teamObject = [self.teamArray objectAtIndex:indexPath.row];
    PlayerListViewController *playerListVC = [[[PlayerListViewController alloc] init] autorelease];
    playerListVC.team = teamObject;
    playerListVC.cdViewController = self;
    [self.navigationController pushViewController:playerListVC animated:YES];
}
在插入一些球隊信息後,可以得到如下效果(按球隊名稱排序):


- (NSArray *)fetchTeamList
{
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *teamEntity = [NSEntityDescription entityForName:@"Team" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:teamEntity];
    
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"name"ascending:YES];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]];
    
    NSError *error = NULL;
    NSArray *array = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
    if (error) {
        NSLog(@"Error : %@\n", [error localizedDescription]);
    }
    
    [fetchRequest release], fetchRequest = nil;
    
    return array;
}
點擊cell,就進入到該隊的球員列表:


- (NSArray *)fetchPlayerList
{
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *teamEntity = [NSEntityDescription entityForName:@"Player" inManagedObjectContext:self.cdViewController.managedObjectContext];
    [fetchRequest setEntity:teamEntity];
    
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"age"ascending:YES];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]];
    
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"team == %@", self.team];
    [fetchRequest setPredicate:predicate];
    
    NSError *error = NULL;
    NSArray *array = [self.cdViewController.managedObjectContext executeFetchRequest:fetchRequest error:&error];
    if (error) {
        NSLog(@"Error : %@\n", [error localizedDescription]);
    }
    
    [fetchRequest release], fetchRequest = nil;
    
    return array;
}
通過導航欄右邊的Add按鈕來添加球員信息:


- (IBAction)addBtnDidClick:(id)sender
{
    // We don't check the user input.
    Player *playerObject = [NSEntityDescription insertNewObjectForEntityForName:@"Player" inManagedObjectContext:self.cdViewController.managedObjectContext];
    playerObject.name = self.nameTextField.text;
    playerObject.age = [NSNumber numberWithInteger:[self.ageTextField.text integerValue]];
    playerObject.team = self.team;
    [self.cdViewController saveContext];
    [self dismissModalViewControllerAnimated:YES];
}


- (IBAction)cancelBtnDidClick:(id)sender
{
    [self dismissModalViewControllerAnimated:YES];
}
以上對NSManagedObject的操作都位於同一份NSManagedObjectContext中。如上麵添加球員的函數addBtnDidClick:所注釋的,添加球員信息時並沒有對數據進行驗證 —— 這將在下一篇討論。

Brief Talk About Core Data Series, Part 5 : Showing in UITableView

Jason Lee @ Hangzhou
Blog : https://blog.csdn.net/jasonblog
Weibo : https://weibo.com/jasonmblog

最後更新:2017-04-04 07:03:39

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