如何將數據從解析保存到NSArray iOS

Question

如何以以下格式將數據從解析保存到NSArray 。 它用於填充UITableView ，該UITableView將用於搜索欄。

_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];

我嘗試了下面的代碼，但是id沒有加載任何數據，當我通過NSLog運行它時，它始終將值返回為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);

是否有將數據保存在上述類型的數組中的方法？

Answer 1

你的糖果從哪里來？ 如果它是一個自定義類，則很可能不會保存為首先進行解析。

這是使用現有數據的一種方法，但是創建PFObject子類也許更好。 （在文檔中檢查）

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，下一步是檢索它們。 （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，如果您想將它們保存回數組中，如您最初提出的問題

Answer 2

之所以為null的原因是

findObjectsInBackgroundWithBlock

該日志語句運行時尚未完成。 如果要處理結果（或記錄結果），則需要將log語句放入塊中，或者可以使用

findObjectsInBackgroundWithTarget:selector:

而是在您的回調方法中包含處理代碼。

Answer 3

我認為您尚未分配數組，因此請按以下方式更改代碼

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);