Core Data浅谈系列之五 ： 在UITableView中展示

Core Data浅谈系列之五 ： 在UITableView中展示

在逻辑上（表关系）将Team和Player关联起来后，我们将其展现到UI视图上。

首先，为App添加导航栏：

[cpp] ​​view plain​​​ ​​​copy​​ 1. @interface AppDelegate : UIResponder 2. 3. @property (strong, nonatomic) UIWindow *window;4. @property (strong, nonatomic) UINavigationController *navController;5. @property (strong, nonatomic) ViewController *viewController;6. 7. @end8. 9. 10. @implementation AppDelegate11. 12. - (void)dealloc13. {14. [_window release];15. [_navController release];16. [_viewController release];17. [super dealloc];18. }19. 20. - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions21. {22. self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];23. // Override point for customization after application launch.24. "ViewController" bundle:nil] autorelease];25. self.navController = [[[UINavigationController alloc] initWithRootViewController:self.viewController] autorelease];26. self.window.rootViewController = self.navController;27. [self.window makeKeyAndVisible];28. return YES;29. }

然后在ViewController上添加一个UITableView，布局好并实现如下相应的代理函数：

[cpp] ​​view plain​​​ ​​​copy​​ 1. #pragma mark -2. #pragma mark - UITableView DataSource3. 4. - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView5. {6. return 1;7. }8. 9. - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section10. {11. return [self.teamArray count];12. }13. 14. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath15. {16. static NSString *cellIdentifier = @"TeamTableViewCellIdentifier";17. UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];18. if (nil == cell) {19. cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier] autorelease];20. }21. 22. Team *teamObject = [self.teamArray objectAtIndex:indexPath.row];23. "nba@2x.jpg"];24. cell.imageView.image = nbaImage;25. cell.imageView.backgroundColor = [UIColorredColor];26. cell.textLabel.text = teamObject.name;27. cell.detailTextLabel.text = teamObject.city;28. cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;29. 30. return cell;31. }32. 33. #pragma mark -34. #pragma mark - UITableView Delegate35. 36. - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath37. {38. [tableView deselectRowAtIndexPath:indexPath animated:YES];39. 40. Team *teamObject = [self.teamArray objectAtIndex:indexPath.row];41. PlayerListViewController *playerListVC = [[[PlayerListViewController alloc] init] autorelease];42. playerListVC.team = teamObject;43. playerListVC.cdViewController = self;44. [self.navigationController pushViewController:playerListVC animated:YES];45. }

在插入一些球队信息后，可以得到如下效果（按球队名称排序）：

[cpp] ​​view plain​​​ ​​​copy​​ 1. - (NSArray *)fetchTeamList2. {3. NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];4. "Team" inManagedObjectContext:self.managedObjectContext];5. [fetchRequest setEntity:teamEntity];6. 7. "name"ascending:YES];8. [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]];9. 10. NSError *error = NULL;11. NSArray *array = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];12. if (error) {13. "Error : %@\n", [error localizedDescription]);14. }15. 16. [fetchRequest release], fetchRequest = nil;17. 18. return array;19. }

[cpp] ​​view plain​​​ ​​​copy​​ 1. - (NSArray *)fetchPlayerList2. {3. NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];4. "Player" inManagedObjectContext:self.cdViewController.managedObjectContext];5. [fetchRequest setEntity:teamEntity];6. 7. "age"ascending:YES];8. [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]];9. 10. "team == %@", self.team];11. [fetchRequest setPredicate:predicate];12. 13. NSError *error = NULL;14. NSArray *array = [self.cdViewController.managedObjectContext executeFetchRequest:fetchRequest error:&error];15. if (error) {16. "Error : %@\n", [error localizedDescription]);17. }18. 19. [fetchRequest release], fetchRequest = nil;20. 21. return array;22. }

通过导航栏右边的Add按钮来添加球员信息：

[cpp] ​​view plain​​​ ​​copy​​ 1. - (IBAction)addBtnDidClick:(id)sender2. {3. // We don't check the user input.4. "Player" inManagedObjectContext:self.cdViewController.managedObjectContext];5. playerObject.name = self.nameTextField.text;6. playerObject.age = [NSNumber numberWithInteger:[self.ageTextField.text integerValue]];7. playerObject.team = self.team;8. [self.cdViewController saveContext];9. [self dismissModalViewControllerAnimated:YES];10. }11. 12. 13. - (IBAction)cancelBtnDidClick:(id)sender14. {15. [self dismissModalViewControllerAnimated:YES];16. }

以上对NSManagedObject的操作都位于同一份NSManagedObjectContext中。如上面添加球员的函数addBtnDidClick:所注释的，添加球员信息时并没有对数据进行验证 —— 这将在下一篇讨论。

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