Question

我是xcode的初学者。我正在创建一个包含多行滚动的问卷类型列表。但是当我选择一行并滚动它并不保持其状态时，当我回来时，它也会失去它的选择。所以任何人都请让我知道如何实现这一点，我尝试过这样的事情，

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if(val==1)
    {
        checkedArr=[[NSMutableArray alloc] init];
        for (int i = 0; i<17; i++)
        {
            [checkedArr addObject:@"1"];
        }
        NSLog(@"Checked arr size %i",[checkedArr count]);

        return 17;
    }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSString *CellIdentifier = [NSString stringWithFormat:@"Cell%i",indexPath.row];
    cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if(cell==nil)
    {
        cell= [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
        cell.textLabel.numberOfLines = 0;
        cell.textLabel.font = [UIFont fontWithName:@"Helvetica" size:14.0];
    }
    cell.textLabel.font = [UIFont fontWithName:@"Helvetica-Bold" size:18.0];

    UIView *selectionColor = [[UIView alloc] init];
    selectionColor.backgroundColor = [UIColor colorWithRed:99/255.0f green:209/255.0f blue:248/255.0f alpha:1.0];
    cell.selectedBackgroundView = selectionColor;

    if([[checkedArr objectAtIndex:indexPath.row] isEqual:@"0"])
    {
        cell.accessoryView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tick.png"]];
        NSLog(@"checkedArr 0000000");
    }
    else if ([[checkedArr objectAtIndex:indexPath.row] isEqual:@"1"])
    {
        cell.accessoryView=nil;
        NSLog(@"checkedArr 111111");
    }


    cell.textLabel.frame=CGRectMake(75.0, 50.0, 150.0, 20.0);
    cell.textLabel.text=[listArray objectAtIndex:indexPath.row];
    NSLog(@"Checked arr size %i",[checkedArr count]);

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    cell=[questionTable cellForRowAtIndexPath:indexPath];
  [checkedArr replaceObjectAtIndex:indexPath.row withObject:@"0"];
    if([[checkedArr objectAtIndex:indexPath.row] isEqual:@"0"])
    {
        cell.accessoryView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tick.png"]];

        NSLog(@"checkedArr 0000000");

    }
    else if ([[checkedArr objectAtIndex:indexPath.row] isEqual:@"1"])
    {[questionTable deselectRowAtIndexPath:indexPath animated:YES];
        cell.accessoryView=nil;
        NSLog(@"checkedArr 111111");
    }

    NSLog(@"Val is %i",val);
    NSLog(@"selected is %@",[listArray objectAtIndex:indexPath.row]);
//    NSLog(@"Checked arr descripton %@",[checkedArr description]);
}

-(void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [tableView cellForRowAtIndexPath:indexPath].accessoryView = UITableViewCellAccessoryNone;
}

Answer 1

在我的应用程序中，我使用相同的代码作为accessoryType的复选标记，请检查此。

将它带入.h文件中的可变数组arSelectedRows;

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  {
   static NSString *CellIdentifier = @"Cell";
     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
 if (cell == nil) {
      cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
  }
  [cell setSelectionStyle:UITableViewCellSelectionStyleGray];

   //Do anything you want for cell here
  if([arSelectedRows containsObject:indexPath]) {
       cell.accessoryType = UITableViewCellAccessoryCheckmark;
 }
  else {
        cell.accessoryType = UITableViewCellAccessoryNone;
  }
 return cell;
}

 #pragma mark - Table view delegate

 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
   if(cell.accessoryType == UITableViewCellAccessoryNone) {
       cell.accessoryType = UITableViewCellAccessoryCheckmark;
       [arSelectedRows addObject:indexPath];
   }
   else {
      cell.accessoryType = UITableViewCellAccessoryNone;
     [arSelectedRows removeObject:indexPath];
 }
 NSLog(@"arSelectedRows are  :%@",arSelectedRows);

 [tableView deselectRowAtIndexPath:indexPath animated:YES];

}

修改

//if you want only single check mark - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [arSelectedRows removeAllObjects]; UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; if(cell.accessoryType == UITableViewCellAccessoryNone) { cell.accessoryType = UITableViewCellAccessoryCheckmark; [arSelectedRows addObject:indexPath]; } else { cell.accessoryType = UITableViewCellAccessoryNone; [arSelectedRows removeObject:indexPath]; } NSLog(@"arSelectedRows are:%@",arSelectedRows); [self.tableview reloadData];//Reload your tableview here }

它会帮助你。

Answer 2

首先，每次向上/向下滚动tableView时，cellForRowAtIndexPath方法都会创建新单元格，这对内存管理来说非常糟糕。

只需在[questionTable deselectRowAtIndexPath:indexPath animated:YES]方法

中删除cellForRowAtIndexPath即可

Answer 3

我认为你需要在下面使用这个api： -

- (void)selectRowAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UITableViewScrollPosition)scrollPosition

Answer 4

如果您正在使用动态单元格，并使用某种类变量（如NSArray）更新行，则可能已将变量设置为弱而不是强。

如何在表视图中维护行的选择状态？

4 个答案: