Question

我正在尝试将字段“field_message_subject”和“field_message_body”中的JSON数据拖到我应用中的表格单元格中。我正在使用以下代码来执行此操作，并且数据已成功返回，但我的应用程序崩溃且标签未填充。崩溃错误是：

由于未捕获的异常'NSRangeException'而终止应用程序，原因： '*** - [__ NSArrayM objectAtIndex：]：索引1超出界限[0 .. 0]'

Viewcontroller.m

    - (void)viewDidLoad {
        [super viewDidLoad];


        NSDictionary *entityData = [NSDictionary dictionaryWithObject:[NSString stringWithFormat:@"1"] forKey:@"uid"];

        [DIOSEntity
         entityGet:entityData
         name:@"entity_message"
         eid:@"uid"
         success:^(AFHTTPRequestOperation *op, id response) {
             self.messages = [NSMutableArray arrayWithObject:(NSDictionary*)response];

             dispatch_async(dispatch_get_main_queue(), ^(void){
                  [self.tableView reloadData];
             });
         }
         failure:^(AFHTTPRequestOperation *op, NSError *err) { NSLog(@"failed to get data"); }
         ];

}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{


    static NSString *PointsTableIdentifier = @"MyMessagesCell";

    MyMessagesCell *cell = (MyMessagesCell *)[tableView dequeueReusableCellWithIdentifier:PointsTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"MyMessagesCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];

    }

    NSDictionary *receivedSubjectLine = [self.messages objectAtIndex:indexPath.row];
   [[cell subjectLine] setText:[receivedSubjectLine objectForKey:@"field_message_subject"]];
    NSLog(@"Received message subject is here %@", receivedSubjectLine);

 return cell;

}

请参阅下面返回的JSON格式：

 2016-02-02 10:37:19.996 app[4208:1406692] Messages are as follows (
            {
            arguments =         (
            );
            data =         (
            );
            "field_message_body" =         {
                und =             (
                                    {
                        format = "<null>";
                        "safe_value" = "Testing message center";
                        value = "Testing message center";
                    }
                );
            };
            "field_message_group_ref" =         (
            );
            "field_message_subject" =         {
                und =             (
                                    {
                        format = "<null>";
                        "safe_value" = Testing;
                        value = Testing;
                    }
                );
            };
            "field_message_user_ref" =         (
            );
            language = en;
            mid = 1;
            "rdf_mapping" =         (
            );
            timestamp = 1447260780;
            type = "private_message";
            uid = 1;
        }
    )

Answer 1

tableview应该知道它需要多少个单元格。定义此tableviewdatasource方法以设置所需的行数。

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.messages count];
}

顺便说一下，如果你增加行数，你应该在viewDidLoad中初始化self.messages并添加条目{h} {/ p>

addObject:

因为这将始终为您的数组分配新空间，其大小始终为1。

修改

self.messages = [NSMutableArray arrayWithObject:(NSDictionary*)response];

在字段NSDictionary *receivedSubjectLine = [self.messages objectAtIndex:indexPath.row]; NSArray * val = receivedSubjectLine[@"und"]; NSString *textToWrite = val[0][@"value"]; [cell.subjectLine setText:textToWrite];
中写入文字

Answer 2

根据您的JSON格式，访问field_message_subject应该类似于

 [[[[receivedSubjectLine objectForKey:@"field_message_subject"] objectForKey:@"und"] objectAtIndex:0] objectForKey:@"value"];

Answer 3

您要将response（NSDictionary）添加到self.messages。您在代码中的其他位置插入self.messages。因此messages数组将始终包含一个值。您正尝试从messages数组获取行索引处的对象。因此，如果行数超过1，您的应用程序将崩溃，因为messages只包含一个对象。

使用返回的JSON

3 个答案: