我有500条记录的解析类或表，现在我需要得到10个随机记录了500条记录？

请告诉我，我怎么能做到这一点。

  ParseQuery＆LT;的parseObject＆GT;查询= ParseQuery.getQuery（parseTableName）;
 query.setLimit（10）;
 query.findInBackground（新FindCallback＆LT;的parseObject＆GT;（）{
     @覆盖
     公共无效完成（名单＆LT;的parseObject＆GT; parseObjects，com.parse.ParseException E）{
     }
 }
 

解决方案

最好的办法可能是编写下载500个对象云code模块中，然后随机选择10在响应向下发送到你的Andr​​oid应用。这比下载500个对象到您的设备，并选择10更好。

它已经因为我已经写了云code一段时间，但你可以做类似下面的。

在iOS应用程序（你可以做一些工作，找了Android当量）：

  [PFCloud callFunctionInBackground：@get500objwithParameters：@ {}块：^（ID结果，NSError *错误）{
   //做一些与结果
}];
 

在云code（这应该是因为它是未经检验视为伪code）：

  Parse.Cloud.define（get500obj'，功能（请求，响应）{
    获取随机元素//
    Array.prototype.randomElement =功能（）{
        返回此[Math.floor（的Math.random（）* this.length）]
    }

    VAR的查询=新Parse.Query（你的对象类名）;
    query.find（{
        成功：函数（结果）{
            变种final10 = [];
            为（变种I = 0; I＆小于10;我++）{
                VAR myRandomElement = results.randomElement（）
                如果（final10.indexOf（myRandomElement）== -1）{
                    final10.push（myRandomElement）;
                } 其他 {
                    一世 - ;
                }
            }
            response.success（final10）;
        }，
        错误：函数（）{
            response.error（错误）;
        }
    }）;
}）;
 

I have 500 records on parse class or table and now i need to get 10 random records out of 500 records?

Please tell me how can I do this.

 ParseQuery<ParseObject> query = ParseQuery.getQuery(parseTableName);
 query.setLimit(10);
 query.findInBackground(new FindCallback<ParseObject>() {
     @Override
     public void done(List<ParseObject> parseObjects,com.parse.ParseException e) {
     }
 }

The best way is probably to write a CloudCode module that downloads 500 objects, then randomly selects 10 to send down to your Android app in the response. That's much better than downloading 500 objects to your device and choosing 10.

It's been a while since I've written CloudCode, but you could do something like the following.

in iOS app (you can do a little work to find the Android equivalent):

[PFCloud callFunctionInBackground:@"get500obj" withParameters:@{} block:^(id result, NSError *error) {
   // do something with result
}];

in CloudCode (this should be treated as pseudocode as it's untested):

Parse.Cloud.define('get500obj', function(request, response) {
    // for getting random element
    Array.prototype.randomElement = function () {
        return this[Math.floor(Math.random() * this.length)]
    }

    var query = new Parse.Query("your-object-class-name");
    query.find({
        success: function(results) {
            var final10 = [];
            for (var i = 0; i < 10; i++) {
                var myRandomElement = results.randomElement()
                if (final10.indexOf(myRandomElement) == -1) {
                    final10.push(myRandomElement);
                } else {
                    i--;
                }
            }
            response.success(final10);
        },
        error: function() {
            response.error(error);
        }
    });
});