ios - 合并解析查询并添加到单独的数组

Question

如何组合多个解析查询？我想从 parse.com 查询列 sclink 和 songTitle，然后将它们分别添加到自己的数组中。

还有如何在本地保存查询并调用它？ IF else 声明或其他内容:

NSMutableArray *trackList = [[NSMutableArray alloc] init];
PFQuery *queryTracks = [PFQuery queryWithClassName:@"liveRadioPL"];
NSArray *objects = [queryTracks findObjects]; // Online PFQuery results
[PFObject pinAllInBackground:objects];

[queryTracks selectKeys:@[@"scLink"]];
[queryTracks findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        // The find succeeded.
        totalTracks = (int)objects.count;
        NSLog(@"Successfully retrieved %lu Tracks.", (unsigned long)objects.count);
        // Do something with the found objects
        for (PFObject *object in objects) {

            [trackList addObject:[NSString stringWithFormat:@"%@", [object objectForKey:@"scLink"]]];


        }
    } else {
        // Log details of the failure
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
}];

trackListArray = trackList;


NSMutableArray *trackTitles = [[NSMutableArray alloc] init];

PFQuery *queryTitles = [PFQuery queryWithClassName:@"liveRadioPL"];
NSArray *objectsTitle = [queryTitles findObjects]; // Online PFQuery results
[PFObject pinAllInBackground:objects];

[queryTracks selectKeys:@[@"songTitle"]];
[queryTracks findObjectsInBackgroundWithBlock:^(NSArray *objectsTitle, NSError *error) {
    if (!error) {
        // The find succeeded.
        totalTitles = (int)objectsTitle.count;
        NSLog(@"Successfully retrieved %lu Titles.", (unsigned long)objectsTitle.count);
        // Do something with the found objects
        for (PFObject *object in objects) {

            [trackTitles addObject:[NSString stringWithFormat:@"%@", [object objectForKey:@"songTitle"]]];


        }
    } else {
        // Log details of the failure
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
}];

Answer 1

我不确定您的逻辑是否真的有意义 - 当您只需要 1 个 API 请求时，您正在使用 4 个 API 请求。另外，雅各布是对的，您正在从后台线程填充数组，因此主线程会将其视为空。

我想我明白你想要做什么 - 试试这个

PFQuery *queryTracks = [PFQuery queryWithClassName:@"liveRadioPL"];
// use includeKey if slink and songTitle are pointers to other Parse classes
// from the context of your question you probably don't need to use includeKey
[queryTracks includeKey:"scLink"];
[queryTracks includeKey:"songTitle"]; 
NSArray *objects = [queryTracks findObjects];

NSMutableArray* scLinks = [[NSMutableArray alloc] init];
NSMutableArray* songTitles = [[NSMutableArray alloc] init];

for (PFObject* object in objects) {
[scLinks addObject:object[@"scLink"]];
[songTitles addObject:object[@"songTitles"]];
}

希望这对您有所帮助，祝您好运!