Question

我的tableview中的前3个单元格中有一个标有“松鼠”字样的标签。有没有办法让它如果一个UILabel在我的桌子上的多个单元格中说“松鼠”，只显示三个中的第一个单元格？

例如如果tableviewCell中的UILabel userName等于@“Squirrels”，则只显示一个表查看包含UILabel中的Squirrels的表格中的单元格

希望这是有道理的。提前谢谢！

编辑：我已成功检索到包含多个常用“名称”值的第一个数组（请参阅下面的代码编辑）。也就是说，当我尝试在我的tableview中显示这些值（firstFoundObject）时，我得到以下崩溃错误：

- [__ NSDictionaryI objectAtIndex：]：无法识别的选择器发送到实例0x1c01a5a20 2017-10-03 23：01：51.728128-0700 pawswap [623：85420] ***由于未捕获的异常而终止应用程序 'NSInvalidArgumentException'，原因：' - [__ NSDictionaryI objectAtIndex：]：无法识别的选择器发送到实例0x1c01a5a20'

ViewController.m

- (int)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    NSString *nodeTitle = self.messages[0][@"name"];

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name == %@", nodeTitle];
    NSArray *filteredArray = [self.messages filteredArrayUsingPredicate:predicate];
    id firstFoundObject = nil;
    firstFoundObject =  filteredArray.count > 0 ? filteredArray.firstObject : nil;

    NSMutableArray *firstObjects = firstFoundObject;

   return [firstObjects count];


}


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

    NSString *nodeTitle = self.messages[0][@"name"];

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name == %@", nodeTitle];
    NSArray *filteredArray = [self.messages filteredArrayUsingPredicate:predicate];
    id firstFoundObject = nil;
    firstFoundObject =  filteredArray.count > 0 ? filteredArray.firstObject : nil;

    NSMutableArray *firstObjects = firstFoundObject;

    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 = [firstObjects objectAtIndex:indexPath.row];

    NSString *messageSubject = [receivedSubjectLine objectForKey:@"node_title"];


    [cell.subjectLine setText:messageSubject];



    NSDictionary *fromUser = [firstObjects objectAtIndex:indexPath.row];

    NSString *userName = [fromUser objectForKey:@"name"];

    [cell.senderName setText:userName];




    NSDictionary *receivedBody = [firstObjects objectAtIndex:indexPath.row];

    NSString *messageBody = [receivedBody objectForKey:@"body"];

    [cell.fullMessage setText:messageBody];




    NSDictionary *messageReceived = [firstObjects objectAtIndex:indexPath.row];

    NSString *timeReceived = [messageReceived objectForKey:@"published at"];

    NSLog(@"Message Received at %@", timeReceived);

    [cell.receivedStamp setText:timeReceived];




    return cell;

}

PREVIOUS

ViewController.m

#pragma mark - Table view data source

- (int)numberOfSectionsInTableView: (UITableView *)tableview
{
    return 1;
}

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

- (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];
    NSString *messageSubject = [receivedSubjectLine objectForKey:@"node_title"];
    [cell.subjectLine setText:messageSubject];

    NSDictionary *fromUser = [self.messages objectAtIndex:indexPath.row];
    NSString *userName = [fromUser objectForKey:@"name"];
    [cell.senderName setText:userName];

    NSDictionary *receivedBody = [self.messages objectAtIndex:indexPath.row];
    NSString *messageBody = [receivedBody objectForKey:@"body"];
    [cell.fullMessage setText:messageBody];

    NSDictionary *messageReceived = [self.messages objectAtIndex:indexPath.row];
    NSString *timeReceived = [messageReceived objectForKey:@"published at"];
    [cell.receivedStamp setText:timeReceived];

    return cell;
}

Answer 1

是的，你可以轻松地做到，您将在运行tableView之前执行此操作，例如：

- (void)viewDidLoad 
{

[super viewDidLoad];


    NSMutableDictionary* NameDictionary=[[NSMutableDictionary alloc] init];

    NSString* PreviousName;

    int oneTime=0;

    for(int i=0;i<[self.messages count];i++){

        NSDictionary *fromUser = [self.messages objectAtIndex: i];

        NSString *userName = [fromUser objectForKey:@"name"];

        if(oneTime==0)
        {

            PreviousName=userName;

            [NameDictionary addObject:[self.messages objectAtIndex: i]];

            oneTime=1;
        }

        if(oneTime!=0)
        {

            if([PreviousName isEqualToString: userName])
            {

            }

            else{

                [NameDictionary addObject:[self.messages objectAtIndex: i]];

            }

            PreviousName=userName;
        }
    }
}

Answer 2

基本上你遇到的问题是由于firstObject是Dictionary类型，你输入的类型为NSMutableArray。请查看以下行：

id firstFoundObject = nil; firstFoundObject = filteredArray.count＆gt; 0 ？ filteredArray.firstObject：nil;

如果您在应用程序中看到filterArray.firstObject为Dictionary，您在firstFoundObject中捕获但稍后在此处输入NSMutableArray：

NSMutableArray * firstObjects = firstFoundObject;

以后当你试图到达这里时，它会崩溃

NSDictionary * receivedSubjectLine = [firstObjects objectAtIndex：indexPath.row];

代码的正确 - 基本版本应该看起来像

- (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];
}

[cell.subjectLine setText:[self.recvMessage objectForKey:@"node_title"]];
[cell.senderName setText:[self.recvMessage objectForKey:@"name"]];
[cell.fullMessage setText:[self.recvMessage objectForKey:@"body"]];
[cell.receivedStamp setText:[self.recvMessage objectForKey:@"published at"]];

return cell;        
}

虽然它没有经过优化，但它仍然适合你。

COUNT ISSUE：

NSMutableDictionary * firstObjects = firstFoundObject;
return [firstObjects count];

在上面的代码中，你有 numberOfRowsInSection ，因为你有firstFoundObject作为字典所以当你调用[firstObjects count]这是一个有效的调用并且它返回字典中的键数时。

您可以修改它：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
{

     NSInteger rowCount = filteredArray.count;
self.recvMessage = rowCount? filteredArray.firstObject: nil;
return rowCount? 1: 0;

}

并且您有新数据实际存储过滤后的对象。

@property (nonatomic) NSDictionary  *recvMessage;

希望这会有所帮助。

Answer 3

当您要求过滤出senderName属性等于@＆＃34; Squirrels＆＃34;的单元格时，您有效地要求在设置后更改数据源。这将导致numberOfRowsInSection方法出现问题，如果在设置数据源之后进行任何过滤，则会返回比您需要的更多的行。

正如您的回答中的一条评论所暗示的那样，＆＃34;制作一个包含self.messages的独特元素并使用此数组的辅助数组。＆＃34;构成tableview数据源的数组不需要过滤。 tableview应该能够呈现它。

如果我有足够的声誉对上述答案发表评论，我会说你是对的，因为自我消息没有改变，所以它不起作用。而不是收集＆＃34;非重复＆＃34;在NameDictionary中的对象，考虑在NSMutableArray中收集它们。这个新的过滤数组应该是数组的数据源。您可能希望在此ViewController之外过滤此数组，以便一旦数组到达此视图控制器，就可以将其分配给self.messages。

如果您希望排除所有重复项，而不是仅显示彼此相邻的重复项，请考虑此answer。

Obj-C：如果进行的单元格包含相同的UILabel值，则只返回1个单元格（顶部单元格）？

3 个答案: