ios - 在NSMutableArray中使用BOOL对象来确定单元状态

我正在使用引用为“ stateArray”的NSMutableArray。 stateArray只需要保存单元格的BOOL值即可确定是否已选择它们。这是我的代码。

我的.h中的stateArray：

@property (nonatomic, strong) NSMutableArray *stateArray;

然后，不合成stateArray。它需要在整个数组中用NO填充，以便在选择单元格时，可以用YES代替NO。目前，此代码为每个单元的stateArray打印0（NSLog在我的if (showCheckmark == YES)中的cellForRowAtIndexPath:中）。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    [[UITableViewCell appearance] setTintColor:[UIColor colorWithHexString:@"#669900"]];

    #define CHECK_NULL_STRING(str) ([str isKindOfClass:[NSNull class]] || !str)?@"":str

    static NSString *CellIdentifier = @"inviteCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    //Customization
    cell.textLabel.highlightedTextColor = [UIColor colorWithHexString:@"#669900"];
    cell.selectionStyle = UITableViewCellSelectionStyleGray;
    cell.backgroundColor = [UIColor blackColor];
    cell.textLabel.textColor = [UIColor whiteColor];
    //Ignore this, it's for UISearchBar
    BOOL isSearching = tableView != self.tableView;
    NSArray *arrayToUse = (isSearching ? searchResults : contactsObjects);
    id p = arrayToUse[indexPath.row];

    NSString *fName = (__bridge_transfer NSString *)(ABRecordCopyValue((__bridge ABRecordRef)(p), kABPersonSortByFirstName));
    NSString *lName = (__bridge_transfer NSString *)(ABRecordCopyValue((__bridge ABRecordRef)(p), kABPersonSortByLastName));
    cell.textLabel.text = [NSString stringWithFormat:@"%@ %@", CHECK_NULL_STRING(fName), CHECK_NULL_STRING(lName)];

    _stateArray = [NSMutableArray array];
    for (int i = 0 ; i != contactsObjects.count ; i++) [_stateArray addObject:@(NO)];

    BOOL showCheckmark = [[_stateArray objectAtIndex:indexPath.row] boolValue];

    if (showCheckmark == YES)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        NSLog(@"It hit showCheckmark = YES, and stateArray is %@",_stateArray[indexPath.row]);
    }
    else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
        NSLog(@"It hit showCheckmark = NO, and stateArray is %@",_stateArray[indexPath.row]);
    }

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath;
{
    id object = contactsObjects[indexPath.row];
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    if (cell.accessoryType == UITableViewCellAccessoryNone)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        [_stateArray replaceObjectAtIndex:indexPath.row withObject:@(YES)];
        [selectedObjects addObject:object];
    }
    else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
        [_stateArray replaceObjectAtIndex:indexPath.row withObject:@(NO)];
        [selectedObjects removeObject:object];
    }

    //slow-motion selection animation.
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

最佳答案

要跟踪选定的项目，请使用Dictionary而不是NSMutableArray，并将indexPath.row保留为键，并将选择保留为对应值。

同样，除了使用BOOL's数组进行这些操作外，还可以如下更新代码。

@property (nonatomic, strong) NSMutableDictionary * selectedRowCollection;

- (void)viewDidLoad{

    self.selectedRowCollection = [[NSMutableDictionary alloc] init];
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath;
{
    id object = contactsObjects[indexPath.row];
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    if (cell.accessoryType == UITableViewCellAccessoryNone)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        [self.selectedRowCollection setObject:@"1" forKey:[NSString stringWithFormat:@"%d",indexPath.row]];
    }
    else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
        [self.selectedRowCollection removeObjectForKey:[NSString stringWithFormat:@"%d",indexPath.row]];
    }

    //slow-motion selection animation.
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

   - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    BOOL showCheckmark =  [[self.selectedRowCollection valueForKey:[NSString stringWithFormat:@"%d",indexPath.row]] boolValue];

    if (showCheckmark == YES)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;

    }
    else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }
}

注意：在重新加载新的tableview数据集时，请不要忘记从字典中删除字典项。