如何從核心數據實體讀取 NSArray

Question

我正在嘗試將 coredata 實體讀入 NSMutableArray 中，但是我不斷收到大量奇怪的數據。 例如，當我取回 NSDictionary 的值時，它看起來像這樣

data: {
    companyName = "WPremium";
    desc = "Test";
    guid = "Otq12342";
    install =     (
        "0x1e59e910 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p851>",
        "0x1e59e8e0 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p848>",
        "0x1e59e830 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p837>",
        "0x1e59e930 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p853>",
        "0x1e59e850 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p839>",
        "0x1e59e890 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p843>",
        "0x1e59e8b0 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p845>",
        "0x1e59e7c0 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p830>",
        "0x1e5957e0 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p829>",
        "0x1e59e810 <x-coredata://BAF7B1AD-F357-455A-B9D7-1288F7D1F652/Install/p835>",
        "(...and 16 more...)"
    );

我想知道如何將 coredata 字典的安裝對象放入 NSArray 中，以便我可以對其進行排序。

更新：這就是我調用 coredata 對象的方式。

- (NSMutableArray *)readSelectedInstall:(NSString *)projIDString {
    NSManagedObjectContext *context = [self managedObjectContext];
    
    
    if (context == nil) {
        NSLog(@"Nil");
    }
    else {
        
        
        NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
        NSEntityDescription *entity = [NSEntityDescription entityForName:@"InstallProject" inManagedObjectContext:context];
        [fetchRequest setEntity:entity];
        
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"projID==%@",projIDString];
        [fetchRequest setPredicate:predicate];
        
        NSError *error;
        
        NSMutableArray *installProjectDictionaryArray = [[NSMutableArray alloc] init];
        
        
        NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
        for (InstallProject *installProj in fetchedObjects) {
            
            NSMutableDictionary *tempInstallProjectDictionaryArray = [[ NSMutableDictionary alloc] init];
            
            [tempInstallProjectDictionaryArray setObject:installProj.companyName forKey:@"CompanyName"];
            [tempInstallProjectDictionaryArray setObject:installProj.projNo forKey:@"ProjNo"];
            [tempInstallProjectDictionaryArray setObject:installProj.desc forKey:@"Desc"];
            [tempInstallProjectDictionaryArray setObject:installProj.guid forKey:@"GUID"];
            [tempInstallProjectDictionaryArray setObject:installProj.projID forKey:@"ProjID"];
            [tempInstallProjectDictionaryArray setObject:installProj.install forKey:@"install"];
            
            [installProjectDictionaryArray addObject:tempInstallProjectDictionaryArray];
        }
        
        return installProjectDictionaryArray;
    }
    return nil;
}

然后使用返回的 NSMutableArray 我這樣做

NSMutableArray *getarray = [self readSelectedInstall:projIDString];
    
    NSMutableDictionary *installsDictionary = [getarray objectAtIndex:0];
    
    NSMutableArray *tempInstalls = [installsDictionary objectForKey:@"install"];
    NSLog(@"%@", tempInstalls);
    
    NSArray *tempSortedItemsArray = [tempInstalls sortedArrayUsingDescriptors:
                                     @[[NSSortDescriptor
                                        sortDescriptorWithKey:@"dp" ascending:YES],
                                     [NSSortDescriptor
                                      sortDescriptorWithKey:@"dc

" ascending:YES]]];
    
    tempInstalls = [tempSortedItemsArray mutableCopy];
    tempSortedItemsArray = nil;
    
    

    
    NSLog(@"%@", tempInstalls);

但在最后一行代碼是我有奇怪輸出的地方。

Answer 1

您需要做的就是從 Core Data 中獲取核心數據 NSManagedObject，install 將作為 NSSet 返回，從外觀上看，它是 NSManagedObjects 的 NSSet。

擁有對象后，您可以訪問“安裝”屬性並根據需要進行排序。

// Get the Core Data Object (Uses Magical Record)
MyObject *object = [MyObject MR_findFirstWithPredicate:[NSPredicate objectPredicate:self.users_id]];
// Sort the object set into an array
NSArray *installs = [object.install sortedArrayUsingDescriptors:@[ [NSSortDescriptor sortDescriptorWithKey:k_timestamp ascending:YES] ]];