Question

我有一个名为masterMessages的对象，其中填充了名为messages的对象。每个消息对象都有五个键：

的ObjectID
senderId
SENDERNAME
消息体
时间戳

基本上我现在正在做的是查询在这个名为masterMessages的对象中发送给我的用户的所有消息。然后我使用：

        self.senderIds = [masterMessages valueForKeyPath:@"@distinctUnionOfObjects.senderId"];

在名为senderIds的数组中获取所有不同的发送者ID（senderId）。有了这个，我将填充我的对话表。但我想用发件人名称（senderName）而不是senderIds填充它。我只是这样做，以防两个用户具有相同的名称。

我想找到：

我怎么说＆＃34;得到valueForKey：@＆＃34; senderName＆＃34;对于此senderId

和

有没有更好的方法来填充我的会话表？

这是我的代码：

注意：即时通讯使用parse.com

  -(void)viewWillAppear:(BOOL)animated{

NSString *userId = [[PFUser currentUser] objectId];

PFQuery *query = [PFQuery queryWithClassName:@"lean"];
[query whereKey:@"recipientId" equalTo:userId];
[query orderByDescending:@"createdAt"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (error) {
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
    else {
        // We found messages!
        masterMessages = objects;

        NSLog(@"self.messages = %@", masterMessages);

        self.senderIds = [masterMessages valueForKeyPath:@"@distinctUnionOfObjects.senderId"];

        NSLog(@"self.senderIds = %@", self.senderIds);


        [self.tableView reloadData];

    }
  }];


}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Return the number of sections.
return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of rows in the section.
return [self.senderIds count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

NSLog(@"self.senderIds = %@", self.senderIds);

NSString *senderDisplayName = [self.senderIds objectAtIndex:indexPath.row];

NSLog(@"sender = %@", senderDisplayName);


cell.textLabel.text = senderDisplayName;


return cell;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
selectedId = [self.senderIds objectAtIndex:indexPath.row];


[self performSegueWithIdentifier:@"ShowMissionMessage" sender:self];



}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.identifier isEqualToString:@"ShowMissionMessage"]) {

    [segue.destinationViewController setHidesBottomBarWhenPushed:YES];
    MissionChat *missionchatviewcontroller = (MissionChat *)segue.destinationViewController;
    missionchatviewcontroller.selectedId = selectedId;
    missionchatviewcontroller.masterMessages = masterMessages;
   }
}

Answer 1

    function findObjectByKey(array, key, value) {
        for (var i = 0; i < array.length; i++) {
            if (array[i][key] === value) {
                return array[i];
            }
        }
        return null;
    }

var obj = findObjectByKey(objArray, 'id', 3);

//ES6

var obj = objArray.find(function (obj) { return obj.id === 3; });

Answer 2

function getObjects(obj, key, val) {
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val));
        } else if (i == key && obj[key] == val) {
            objects.push(obj);
        }
    }
    return objects;
}
var result = getObjects(obj, 'category_id', valu.category_id);
console.log(result);

如何通过键和值获取对象

2 个答案: