iOS XMPP Framework 06 - Roster 上

这一节我们为YDChat添加对Roster的支持，实现好友的添加和显示功能。XMPP框架在XMPPRoster类中已经支持了对roster的处理。在YDAppDelegate的setupStream方法中，我们已经构造并配置了一个xmppRoster的实例。XMPP框架还通过XMPPRosterCoreDataStorage类支持我们将好友列表写入内存、core data或者自定义的存储机制中。

autoFetchRoster标示应用程序在连接到服务器后会自动请求好友列表。

autoAcceptKnownPresenceSubscriptionRequests用于让应用程序只获取在线好友的信息，因为实际的好友列表可能很大，而用户只关心在线的好友。

    // Setup roster    //    // The XMPPRoster handles the xmpp protocol stuff related to the roster.    // The storage for the roster is abstracted.    // So you can use any storage mechanism you want.    // You can store it all in memory, or use core data and store it on disk, or use core data with an in-memory store,    // or setup your own using raw SQLite, or create your own storage mechanism.    // You can do it however you like! It's your application.    // But you do need to provide the roster with some storage facility.        self.xmppRosterStorage = [[XMPPRosterCoreDataStorage alloc] init];    //xmppRosterStorage = [[XMPPRosterCoreDataStorage alloc] initWithInMemoryStore];        self.xmppRoster = [[XMPPRoster alloc] initWithRosterStorage:self.xmppRosterStorage];        self.xmppRoster.autoFetchRoster = YES;    self.xmppRoster.autoAcceptKnownPresenceSubscriptionRequests = YES;

显示好友列表

实现YDContactsViewController，继承于YDBaseViewController。这个类中，有一个UITableView用于显示好友列表。

#import "YDBaseViewController.h"@interface YDContactsViewController : YDBaseViewController@end

声明遵循以下代理协议

#import "YDContactsViewController.h"#import <CoreData/CoreData.h>#import "YDAppDelegate.h"#import "DDLog.h"@interface YDContactsViewController ()<NSFetchedResultsControllerDelegate,UITableViewDataSource,UITableViewDelegate,UIAlertViewDelegate>{    NSFetchedResultsController *fetchedResultsController;}@property (nonatomic,strong) UITableView *mtableView;@end

实现viewDidLoad，创建UITableView并设置自己是其data source和代理

- (void)viewDidLoad{    [super viewDidLoad];    self.view.backgroundColor=[UIColor whiteColor];    self.mtableView = [[UITableView alloc] initWithFrame:CGRectMake(0,86,ScreenWidth,ScreenHeight - 86-40) style:UITableViewStylePlain];     self.mtableView .delegate=self;     self.mtableView .dataSource=self;     self.mtableView .rowHeight=38.0;         self.mtableView .separatorStyle=UITableViewCellSeparatorStyleNone;     self.mtableView .backgroundColor = [UIColor clearColor];    [self.view addSubview:self.mtableView];}

实现fetchResultController，用于从XMPPUserCoreDataStorage获取数据

- (NSFetchedResultsController *)fetchedResultsController{if (fetchedResultsController == nil)        {NSManagedObjectContext *moc = [[self appDelegate] managedObjectContext_roster];NSEntityDescription *entity = [NSEntityDescription entityForName:@"XMPPUserCoreDataStorageObject"                                          inManagedObjectContext:moc];NSSortDescriptor *sd1 = [[NSSortDescriptor alloc] initWithKey:@"sectionNum" ascending:YES];NSSortDescriptor *sd2 = [[NSSortDescriptor alloc] initWithKey:@"displayName" ascending:YES];NSArray *sortDescriptors = [NSArray arrayWithObjects:sd1, sd2, nil];NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];[fetchRequest setEntity:entity];[fetchRequest setSortDescriptors:sortDescriptors];[fetchRequest setFetchBatchSize:10];fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest                                                               managedObjectContext:moc                                                                 sectionNameKeyPath:@"sectionNum"                                                                          cacheName:nil];[fetchedResultsController setDelegate:self];NSError *error = nil;if (![fetchedResultsController performFetch:&error])            {DDLogError(@"Error performing fetch: %@", error);            }                }return fetchedResultsController;}- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller{[self.mtableView reloadData];}

tableView相关的方法：

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#pragma mark UITableViewCell helpers////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////- (void)configurePhotoForCell:(UITableViewCell *)cell user:(XMPPUserCoreDataStorageObject *)user{// Our xmppRosterStorage will cache photos as they arrive from the xmppvCardAvatarModule.// We only need to ask the avatar module for a photo, if the roster doesn't have it.if (user.photo != nil)        {cell.imageView.image = user.photo;        }else        {NSData *photoData = [[[self appDelegate] xmppvCardAvatarModule] photoDataForJID:user.jid];        if (photoData != nil)cell.imageView.image = [UIImage imageWithData:photoData];elsecell.imageView.image = [UIImage imageNamed:@"emptyavatar"];        }}////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#pragma mark UITableView////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{return [[[self fetchedResultsController] sections] count];}- (NSString *)tableView:(UITableView *)sender titleForHeaderInSection:(NSInteger)sectionIndex{NSArray *sections = [[self fetchedResultsController] sections];if (sectionIndex < [sections count])        {id <NSFetchedResultsSectionInfo> sectionInfo = [sections objectAtIndex:sectionIndex];        int section = [sectionInfo.name intValue];switch (section)            {                case 0  : return @"Available";                case 1  : return @"Away";                default : return @"Offline";            }        }return @"";}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)sectionIndex{NSArray *sections = [[self fetchedResultsController] sections];if (sectionIndex < [sections count])        {id <NSFetchedResultsSectionInfo> sectionInfo = [sections objectAtIndex:sectionIndex];return sectionInfo.numberOfObjects;        }return 0;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{static NSString *CellIdentifier = @"Cell";UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];if (cell == nil)        {cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault                                      reuseIdentifier:CellIdentifier];        }XMPPUserCoreDataStorageObject *user = [[self fetchedResultsController] objectAtIndexPath:indexPath];cell.textLabel.text = user.displayName;[self configurePhotoForCell:cell user:user];return cell;}-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{    [tableView deselectRowAtIndexPath:indexPath animated:YES];    //Get our contact record    XMPPUserCoreDataStorageObject *user = [[self fetchedResultsController] objectAtIndexPath:indexPath];    DDLogInfo(@"user %@",user.jidStr);    }

viewWillDisappear

- (void)viewWillDisappear:(BOOL)animated{// do not disconnect to the sever when exit from contacts view controller    //[[self appDelegate] disconnect];[[[self appDelegate] xmppvCardTempModule] removeDelegate:self];[super viewWillDisappear:animated];}

此外还需要修改YDAppDelegate函数，实现通过点击侧边栏在HomeView和ContactsView之间的切换：

-(void)leftMenuSelectionItemClick:(YDMenuItem *)item{        if ([item.controllerTAG length]>0)    {        [self.container setMenuState:YDSLideMenuStateClosed];                if ([item.controllerTAG isEqualToString:kMenuHomeTag])        {            //allocate the View Controller            if (homeViewController == nil)            {                homeViewController = [[YDHomeViewController alloc]init];            }            [self.navigationController popViewControllerAnimated:YES];            //[self.navigationController pushViewController:homeViewController animated:YES];                    }        else if ([item.controllerTAG isEqualToString:kMenuContactsTag])        {            //allocate the View Controller            contactsViewController = [[YDContactsViewController alloc]init];            [self.navigationController popViewControllerAnimated:YES];            [self.navigationController pushViewController:contactsViewController animated:YES];                    }    }}

程序执行效果如下：