Question

我希望在PFObjet内保存值，并将其保存到多个NSMutableArray。让我解释。我从Parse中的Partisipants类下载信息。 Partisipants类包含多个NSString值，例如name，phoneNumber等。我希望从查询的返回值中删除该信息，并将新objectID的每个实例添加到NSMutableArray。假设有多行，或userID来搜索NSMutableArray。

PFQuery *query = [PFQuery queryWithClassName:@"Partisipants"];
    [query setLimit: 600];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            // The find succeeded. The first 600 objects are available in objects
            self.objectsFromParse = objects;
            NSLog(@"%@", self.objectsFromParse);
        } else {
            // Log details of the failure
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];

修改

这是我执行此查询的返回结果（个人信息已被修改）：

(
    "<Partisipants:S420zHiNFT:(null)> {\n    additionalDonation = \"100.00\";\n    emailAddress = \"somewhere@email.com\";\n    emergencyPhone = 12345678901;\n    hasArrived = NO;\n    name = \"James\";\n    phoneNumber = 12345678901;\n}",
    "<Partisipants:9BpoFxO1zx:(null)> {\n    additionalDonation = \"500.00\";\n    emailAddress = \"someguy@email.com\";\n    emergencyPhone = 12345678901;\n    hasArrived = NO;\n    name = \"Michael\";\n    phoneNumber = 12345678901;\n}"
)

Answer 1

如果你想在新的mutableArrays中存储电子邮件，名字，objectId等，你可以这样做：

NSMutableArray * usernames = [NSMutableArray array];
NSMutableArray * emails = [NSMutableArray array];
NSMutableArray * objectIds = [NSMutableArray array];
for (PFObject * participant in objects) {
    if (participant[@"name"]) [usernames addObject:participant[@"name"]];
    if (participant[@"emailAddress"]) [emails addObject:participant[@"emailAddress"]];
    [objectIds addObject:participant.objectId];
}

Answer 2

创建参与者数组。然后循环遍历它们并构建可变数组（nameArray，email array等）。请注意，如果某些参与者数据是可选的，这是一种非常糟糕的方法。例如，您如何表示没有电子邮件地址？你不能在数组中使用nil，所以你必须使用NSNull或空字符串来表示它......

Answer 3

您可能需要KVC的帮助。

#import <Foundation/Foundation.h>

@interface Object : NSObject

@property (nonatomic, strong, readonly) NSString *name;
@property (nonatomic, strong, readonly) NSString *objectId;

- (instancetype)initWithDictionary:(NSDictionary *)dictionary;

@end

@interface Object ()

@property (nonatomic, strong) NSDictionary *dictionary;

@end

@implementation Object

- (instancetype)initWithDictionary:(NSDictionary *)dictionary
{
    if (self = [super init]) {
        self.dictionary = dictionary;
    }
    return self;
}

- (NSString *)name
{
    return self.dictionary[@"name"];
}

- (NSString *)objectId
{
    return self.dictionary[@"objectId"];
}

@end

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Object *object0 = [[Object alloc] initWithDictionary:@{@"name": @"victor", @"objectId": @"001"}];
        Object *object1 = [[Object alloc] initWithDictionary:@{@"name": @"evan", @"objectId": @"002"}];
        Object *object2 = [[Object alloc] initWithDictionary:@{@"name": @"gerry"}];
        Object *object3 = [[Object alloc] initWithDictionary:@{@"name": @"tony", @"objectId": @"004"}];
        NSArray *array = @[object0, object1, object2, object3];

        NSArray *objectIds = [array valueForKey:@"objectId"];
        NSLog(@"%@", objectIds);

        NSArray *names = [array valueForKey:@"name"];
        NSLog(@"%@", names);

        NSArray *filteredObjectIds = [objectIds filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"SELF != nil"]];
        NSLog(@"%@", filteredObjectIds);

        NSMutableArray *mutableArray = [filteredObjectIds mutableCopy];
        NSLog(@"%@", mutableArray);
    }
    return 0;
}

控制台日志：

2017-11-03 16:33:29.092837+0800 Test[50097:3891576] (
    001,
    002,
    "<null>",
    004
)
2017-11-03 16:33:29.093079+0800 Test[50097:3891576] (
    victor,
    evan,
    gerry,
    tony
)
2017-11-03 16:33:29.093317+0800 Test[50097:3891576] (
    001,
    002,
    004
)
2017-11-03 16:33:29.093401+0800 Test[50097:3891576] (
    001,
    002,
    004
)
Program ended with exit code: 0

解析PFObject将结果保存到NSMutableArray

3 个答案: