如何将解析中的数据保存到 NSArray iOS答案

【问题标题】：How to save data from parse to a NSArray iOS如何将解析中的数据保存到 NSArray iOS
【发布时间】：2014-01-31 09:42:27
【问题描述】：

如何以以下格式将解析中的数据保存到NSArray。用于填充UITableView，用于搜索栏。

_candyArray = [NSArray arrayWithObjects:
                  [Candy candyOfCategory:@"chocolate" name:@"chocolate bar" mName:@"test1"],
                  [Candy candyOfCategory:@"chocolate" name:@"chocolate chip" mName:@"test1"],
                  [Candy candyOfCategory:@"chocolate" name:@"dark chocolate" mName:@"test1"],
                  [Candy candyOfCategory:@"hard" name:@"lollipop" mName:@"test1"],
                  [Candy candyOfCategory:@"hard" name:@"candy cane" mName:@"test1"],
                  [Candy candyOfCategory:@"hard" name:@"jaw breaker" mName:@"test1"],
                  [Candy candyOfCategory:@"other" name:@"caramel" mName:@"test1"],
                  [Candy candyOfCategory:@"other" name:@"sour chew" mName:@"test1"],
                  [Candy candyOfCategory:@"other" name:@"peanut butter cup" mName:@"test1"],
                  [Candy candyOfCategory:@"other" name:@"gummi bear" mName:@"test1"], nil];

我尝试了下面的代码，但是 id 没有加载任何数据，当我通过NSLog 运行它时，它一直返回值null

PFQuery *query = [PFQuery queryWithClassName:self.parseClassName];
[query orderByAscending:@"Name"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        {
            self.arrayName = objects;
        }   
    }else {
        NSLog(@"Error, %@ %@",error,[error userInfo]);
    }
}];

NSLog(@"Array : %@", arrayName);

有没有办法将数据保存在上述类型的数组中？

【问题讨论】：

您是否NSLog() NSArray *objects 以确保您确实收到了所需的对象？
尝试在findObjectsInBackgroundWithBlock:的块内登录
它有效，虽然它在块中，但它仍然没有显示在上面的数组中
@mugunthan 你的NSLog(@"Array : %@", arrayName); 将在findObjectsInBackgroundWithBlock 完成之前工作
_candyArray 输出为“”、“”、“”、“”、“ ", "", "", "", "", "" 而来自 parse.com 的输出“<0gc8p3abia:>

标签： ios objective-c nsarray parse-platform pfquery

【解决方案1】：

你的糖果是从哪里来的？如果是自定义类，那么很可能一开始就不会保存解析。

这是使用现有数据的一种方法，但也许最好创建一个 PFObject 子类。（检查文档）

NSMutableArray * candyObjects = [NSMutableArray alloc]init];

for (Candy * candy in _candyArray) {   
    PFObject * newCandy = [PFObject objectWithClassName:@"Candy"];
    newCandy[@"category"] = candy.category; // or however you store your candy object's properties
    newCandy[@"name"] = candy.name; // I prefer lowercase names, I notice you're querying uppercase
    newCandy[@"mName"] = candy.mName;

    [candyObjects addObject:newCandy];
}

[PFObject saveAll:candyObjects]; // should run in background, but for now just showing to save.

好的，下一步是检索它们。（基本上是 rajjjjj 的示例，有一些更改）

PFQuery *query = [PFQuery queryWithClassName:@"Candy"];
[query orderByAscending:@"name"]; // lowercase to match above
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        NSLog(@"retrievedObjects:%@", objects);

        // Now to get them back into an array like you wanted before
        // again, perhaps you could skip this by subclassing your candy ob

        for (PFObject * obbie in objects) {
            // mutableArrayRef represents wherever you'd like your candies added.
            // make sure it has memory allocated, and it has been initialized
            [mutableArrayRef addObject:[Candy candyOfCategory:obbie[@"category"] name:obbie[@"name"] mName:obbie[@"mName"]]];
        }

        // now continue in whatever way you please, all of your candy should be in mutableArrayRef
        // if you're doing multiple searches, make sure you clear the array before adding
        // otherwise you will stack the data and get undesired results
    }
    else {
        NSLog(@"Error, %@ %@",error,[error userInfo]);
    }
}];

然后，如果您想按照您最初的问题将它们保存回数组中

【讨论】：

【解决方案2】：

它为空的原因是

findObjectsInBackgroundWithBlock

运行该日志语句时未完成。如果要处理结果（或记录），则需要将 log 语句放在块内，也可以使用

findObjectsInBackgroundWithTarget:selector:

而是在你的回调方法中包含处理代码。

【讨论】：

【解决方案3】：

我认为您尚未分配数组，因此请按如下方式更改您的代码

PFQuery *query = [PFQuery queryWithClassName:self.parseClassName];
[query orderByAscending:@"Name"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
    {
        self.arrayName = [[NSArray alloc]initwithArray:objects];
    }   
}else {
    NSLog(@"Error, %@ %@",error,[error userInfo]);
}
}];

NSLog(@"Array : %@", self.arrayName);

【讨论】：