xmPP(即时通讯)向远程服务器请求数据

首先在本地初始化一个数据库

- (void)initDatabase

{

    //最终数据库路径

    NSString *dbPath  = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/database.db"];

    NSFileManager *fm = [NSFileManager defaultManager];

    if(![fm fileExistsAtPath:dbPath])

    {

        EGODatabase* database = [EGODatabase databaseWithPath:dbPath];

strSql = @"creat table if not exists notice(id integer primary key asc,noticeid text,title text, image text,content text,timestamp text);";

        [database executeQuery:strSql];

        [database close];

 ｝

然后保存信息在本地数据库，因为我做的时资讯，所以有一个判断，如果本地已经有这个资讯则直接返回，如果有更新资讯就插入最新的资讯

-(void)saveNotice:(NoticeMessage *)notice

{

    NSString *dbPath  = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/database.db"];

    EGODatabase* database = [EGODatabase databaseWithPath:dbPath];

    //查询是否已经存在，如果存在就直接返回不插入

    NSString *sqlQuery = [[NSString alloc]initWithFormat:@"select count(*) from notice where noticeid = %@",notice.strnotId];

    //NSLog(@"%@",sqlQuery);

    EGODatabaseResult *result = [database executeQuery:sqlQuery];

    for(EGODatabaseRow* row in result) {

        NSString* strTotal = [row stringForColumnAtIndex:0];

        if ([strTotal integerValue] > 0) {

            return;

        }

    }

        NSString* sqlInsert = [[NSString alloc] initWithFormat:@"insert into notice(noticeid,title,date,image,content,timestamp) values(‘%@‘,‘%@‘,‘%@‘,‘%@‘,‘%@‘,‘%@‘)",notice.strNoticeId,notice.strTitle,notice.strDate,notice.strImage,notice.strContent,notice.strTimeStamp];

    [database executeQuery:sqlInsert];

    NSLog(@"save message:%@",sqlInsert);

    [database close];

}

 我们在与服务器端同事沟通时做了一个资讯的id，通过ID判断是否最新资讯，所以会查询一下本地数据库里的id，那么我就抽出了这个数据库方法，将这个id赋给一个全局变量，

在把这个全局变量赋给后面的请求。

//检查本地公告id

-(void)searchNoticeDataBase

{

    EGODatabase* database = [EGODatabase databaseWithPath:[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/database.db"]];

    //查询是否已经存在最新公告

    NSString *sqlQuery = [[NSString alloc]initWithFormat:@"select noticeid from notice group by category order by noticeid limit 1"];

    //NSLog(@"%@",sqlQuery);

    EGODatabaseResult *result = [database executeQuery:sqlQuery];

    for(EGODatabaseRow* row in result)

        {

        NoticeMessage *msg = [[NoticeMessage alloc]init];

        msg.strnotId = [row stringForColumn:@"noticeid"];

            noticeId = msg.strnotId;

          }

    [database close];

}

请求的方法

-(void)checkNewNotice

{

    NSUserDefaults *pref = [NSUserDefaults standardUserDefaults];

    NSString* strToken = [pref stringForKey:@"logintoken"];

    NSString *oldNoticeId = noticeId;

    if (oldNoticeId == nil) {

        oldNoticeId = @"0";

    }

    //向管理平台登录，获取token

    NSString *strUrl = [NSString stringWithFormat:@"http://xxx.xx.x.xxx:xxxx/fxxxxxxxx?xxxx=%@&xxxx=%@",strToken,oldNoticeId];

    NSLog(@"Chect new info %@",strUrl);

    NSURL *url = [NSURL URLWithString:strUrl];

    __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

    [request setCompletionBlock:^{

        // Use when fetching text data

        NSString *responseString = [request responseString];

        NSLog(@"login result:%@",responseString);

        NSError *error = nil;

        NSData *jsonData = [responseString dataUsingEncoding:NSUTF8StringEncoding];

        NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error];

        NSString* msgCode = [dict objectForKey:@"code"];

        if ([msgCode isEqualToString:@"200"]) {

            NSLog(@"get new info success!");

            NSDictionary *noticeDict = [dict objectForKey:@"result"];

            for (NSDictionary* dResult in noticeDict) {

                NSString *strNoticeId = [dResult objectForKey:@"noticeid"];

                NSString *strTitle = [dResult objectForKey:@"title"];

                NSString *strDate = [dResult objectForKey:@"date"];

                NSString *strImage = [dResult objectForKey:@"image"];

                NSString *strContent = [dResult objectForKey:@"content"];

                NSString *strTimeStamp = [dResult objectForKey:@"timestamp"];

                NoticeMessage *notice = [[NoticeMessage alloc]init];

                notice.strNoticeId = strNoticeId;

                notice.strTitle = strTitle;

                notice.strDate = strDate;

                notice.strImage = strImage;

                notice.strContent = strContent;

                notice.strTimeStamp = strTimeStamp;

                [self saveNotice:notice];

            }

            //重新加载资讯信息

            [self loadNotice];

            [self.tableValued reloadData];

            //   [SVProgressHUD dismiss];

        }

        else if([msgCode isEqualToString:@"404"]) {

            NSLog(@"找不到用户");

            //  [SVProgressHUD showErrorWithStatus:@"用户名或密码有误"];

            return;

        }

        else{

            ;// [SVProgressHUD dismiss];

        }

        NSLog(@"msgCode is %@",msgCode);

        // Use when fetching binary data

        //NSData *responseData = [request responseData];

    }];

    [request setFailedBlock:^{

        NSError *error = [request error];

        NSLog(@"login result:%@",error.description);

    }];

    [request startAsynchronous];

}

还需要一个从数据库载入的方法

- (void)loadNotice

{

    if (!arrayNotice) {

        arrayNotice = [[NSMutableArray alloc]init];

    }

    EGODatabase* database = [EGODatabase databaseWithPath:[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/database.db"]];

    //查询所有的公告

    NSString *sqlQuery = [[NSString alloc]initWithFormat:@"select distinct * from notice  order by timestamp"];

    //NSLog(@"%@",sqlQuery);

    EGODatabaseResult *result = [database executeQuery:sqlQuery];

    for(EGODatabaseRow* row in result) {

        NoticeMessage *msg = [[NoticeMessage alloc]init];

        msg.strNoticeId = [row stringForColumn:@"noticeid"];

        msg.strTitle = [row stringForColumn:@"title"];

        msg.strContent = [row stringForColumn:@"content"];

        msg.strTimeStamp = [row stringForColumn:@"timestamp"];

        [arrayNotice insertObject:msg atIndex:0];

    }

    [database close];

}

那么最后，我是在登录的时候调用请求的方法

[self checkNewNotice]

说实话我还是个小菜鸟，这个项目真的帮助我提升了许多，虽然很多还是不懂，但我都觉得我已经是高富帅了

原文：http://www.cnblogs.com/tuhaoYY/p/3850894.html