iphone – UITableView中的选中标记

但是当我滚动tableview时,它不仅在tableview单元格上有一个复选标记.
它也显示在另一个细胞上.

这有什么问题？

self.dataAry = [NSArray arrayWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"10",@"11",@"12",@"13",@"14",@"15",@"16",@"17",@"18",@"19",nil];
marks = [NSMutableArray new];
for (int i = 0 ; i < [self.dataAry count]; i++) {
    [marks addObject:@"NO"];
}

- (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] autorelease];
}
cell.textLabel.text = [dataAry objectATindex:indexPath.row];
if ([[marks objectATindex:indexPath.row] isEqualToString:@"YES"]) {
    [cell setAccessoryType:UITableViewCellAccessorycheckmark];
}else {
    [cell setAccessoryType:UITableViewCellAccessoryNone];
}
// Configure the cell.

return cell;}
- (void)tableView:(UITableView *)tableView didSELEctRowATindexPath:(NSIndexPath *)indexPath{

UITableViewCell *thisCell = [tableView cellForRowATindexPath:indexPath];


if ([[tableView cellForRowATindexPath:indexPath] accessoryType] == UITableViewCellAccessorycheckmark){
        [[tableView cellForRowATindexPath:indexPath] setAccessoryType:UITableViewCellAccessoryNone];
        [SELEctArray removeObject:[self.dataAry objectATindex:indexPath.row]];
        [marks replaceObjectATindex:indexPath.row withObject:@"NO"];
    }
    else {
        [[tableView cellForRowATindexPath:indexPath] setAccessoryType:UITableViewCellAccessorycheckmark];
        [SELEctArray addObject:[self.dataAry objectATindex:indexPath.row]];
        [marks replaceObjectATindex:indexPath.row withObject:@"YES"];
    }
}