AVOS Cloud 学习笔记（二） 功能总结（What it can do？）

AVOS Cloud 学习笔记（一）   功能总结（What it can do？）

第一章、对象存储

1. 对象新建、保存、更新、删除和检索

   1 //创建新对象，根据类名
   2 AVObject *gameScore = [AVObject objectWithClassName:@"GameScore"];
   3 [gameScore setObject:[NSNumber numberWithInt:1337] forKey:@"score"];
   4 [gameScore setObject:@"Steve" forKey:@"playerName"];
   5 [gameScore setObject:[NSNumber numberWithBool:NO] forKey:@"cheatMode"];
   6 [gameScore save];

   1 //保存对象到服务器
   2 [gameScore save];
   3 //后台保存
   4 [gameScore saveInBackground];
   5 [gameScore saveInBackgroundWithBlock:^(BOOL successed, NSError* error){/*do somthing*/}];e

   1 //更新
   2 [gameScore refresh]

   1 //删除对象
   2 [gameScore deleteInBackground];
   3 [gameScore deleteInBackgroundWithBlock:...];
   4 [gameScire delete]//不推荐

   1 //如果有objectId的话
   2 AVQuery *query = [AVQuery queryWithClassName:@"GameScore"];
   3 AVObject *gameScore = [query getObjectWithId:@"51a90302e4b0d034f61623b5"];
   4 //访问对象的属性
   5 int score = [[game Score objectForKey:"score"]intValue];

2. 计数器和数组

   1 //计数器
   2 [gameScore incrementKey:@"score"];
   3 [gameScore saveInBackground];
   4 //数组 添加元素到数组末尾
   5 [gameScore addOject:"100" forKey:"some"];
   6 //添加元素到对应位置，如果字段不存在，就创建
   7 [gameSocre addUniqueObject:""forKey"ss"];
   8 //移除
   9 [gameScore removeObject: forKey:];

3. 对象离线存储和离线情况下从缓存加载

    1 // Create the object.
    2 AVObject *gameScore = [AVObject objectWithClassName:@"GameScore"];
    3 [gameScore setObject:[NSNumber numberWithInt:1337] forKey:@"score"];
    4 [gameScore setObject:@"Sean Plott" forKey:@"playerName"];
    5 [gameScore setObject:[NSNumber numberWithBool:NO] forKey:@"cheatMode"];
    6 [gameScore setObject:[NSArray arrayWithObjects:@"pwnage", @"flying", nil] forKey:@"skills"];
    7 [gameScore saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
    8
    9     [gameScore setObject:[NSNumber numberWithBool:YES] forKey:@"cheatMode"];
   10     [gameScore setObject:[NSNumber numberWithInt:1338] forKey:@"score"];
   11     [gameScore saveEventually];
   12 }];

   AVQuery *query = [AVQuery queryWithClassName:@"GameScore"];
   query.cachePolicy = kPFCachePolicyNetworkElseCache;
   /*
   kPFCachePolicyIgnoreCache 查询行为不从缓存中加载，也不会将结果保存到缓存中。
   kPFCachePolicyIgnoreCache 是默认的缓存策略。
   kPFCachePolicyCacheOnly    查询行为会忽略网络状况，只从缓存中加载。如果没有缓存的结果，这个策略会导致一个 AVError
   kPFCachePolicyCacheElseNetwork -- 查询行为首先尝试从缓存中加载，如果加载失败, 它会通过网络加载结果。如果缓存和网络中获取的行为都失败了，会有一个 AVError
   kPFCachePolicyNetworkElseCache -- 查询行为首先尝试从网络中加载，如果加载失败, 它会从缓存中加载结果。如果缓存和网络中获取的行为都失败了，会有一个 AVError
   kPFCachePolicyCacheThenNetwork -- 查询首先从缓存中加载，然后从网络加载。在这种情况下, 回调函数会被调用两次，第一次是缓存中的结果，然后是从网络获取的结果。因为它在不同的时间返回两个结果，这个缓存策略不能和 findObjects 同时使用。
   */
   //设置缓存有效期
   query.maxCacheAge = 24*3600;
   
   [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
     if (!error) {
       // Results were successfully found, looking first on the
       // network and then on disk.
     } else {
       // The network was inaccessible and we have no cached data for
       // this query.
     }
   }];
   
   // Then, elsewhere in your code...
   AVQuery *query = [AVQuery queryWithClassName:@"GameScore"];
   query.cachePolicy = kPFCachePolicyNetworkElseCache;
   [query findObjectsInBackgroundWithTarget:self
                                   selector:@selector(findCallback:error:)];

4. 关系型数据

    1 //1对1 对象关联
    2 // Create the post
    3 AVObject *myPost = [AVObject objectWithClassName:@"Post"];
    4 [myPost setObject:@"I‘m Smith" forKey:@"title"];
    5 [myPost setObject:@"Where should we go for lunch?" forKey:@"content"];
    6
    7 // Create the comment
    8 AVObject *myComment = [AVObject objectWithClassName:@"Comment"];
    9 [myComment setObject:@"Let‘s do Sushirrito." forKey:@"content"];
   10
   11 // Add a one-one relation between the Post and Comment
   12 [myComment setObject:myPost forKey:@"parent"];
   13
   14 // This will save both myPost and myComment
   15 [myComment saveInBackground];
   16
   17 //也可以不要对象，用objectId关联
   18 // Add a relation between the Post with objectId "51a902d3e4b0d034f6162367" and the comment
   19 [myComment setObject:[AVObject objectWithoutDataWithClassName:@"Post" objectId:@"51a902d3e4b0d034f6162367"]
   20               forKey:@"parent"];
   21
   22 //n对n
   23 AVUser *user = [AVUser currentUser];
   24 AVRelation *relation = [user relationforKey:@"likes"];
   25 [relation addObject:post];
   26 [user saveInBackground];
   27 [relation removeObject:post];

第二章、数据查询

第三章、ACL权限控制

第四章、文件

第五章、用户

第六章、地理位置

第七章、调用云代码

第八章、消息推送

第九章、SNS组件

第十章、事件流

第十一章、反馈

第十二章、应用内搜索

第十三章、应用间数据绑定

AVOS Cloud 学习笔记（二） 功能总结（What it can do？）,布布扣,bubuko.com