iOS：Tableview多選 - AccessoryCheckmark檢查可重復使用的單元格

Question

我正在使用帶有節和多個選擇的tableview，但是當選擇一行時我有一個問題，即檢查多行...我已經看到了一些其他線程，但是沒有真正得到解決方案。 ..

這是我的代碼：

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *) indexPath
{    
    [employeeTable deselectRowAtIndexPath:[employeeTable indexPathForSelectedRow] animated:NO];

    UITableViewCell *cell = [employeeTable cellForRowAtIndexPath:indexPath];    

    // get the letter in each section
    NSString *alphabet = [charIndex objectAtIndex:indexPath.section];

    // get the names beginning with the letter
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", alphabet];    

    NSArray *names = [listOfNames filteredArrayUsingPredicate:predicate];    

    NSString *name = [names objectAtIndex:indexPath.row];

    for(int i = 0; i < [employeeConnection.employees count]; i++)
    {
        Employee *aEmployee = [employeeConnection.employees objectAtIndex:i];

        NSString *firstName = aEmployee.firstName;
        NSString *lastName = aEmployee.lastName;
        NSString *fullName = [NSString stringWithFormat:@"%@ %@", firstName, lastName];

        if([fullName isEqualToString:name])
        { 
            NSLog(@"Name: %@", name);

            if (cell.accessoryType == UITableViewCellAccessoryNone) {

                cell.accessoryType = UITableViewCellAccessoryCheckmark;

                // Reflect selection in data model
                [chosenEmployees addObject:aEmployee.employeeID];
                [chosenEmployeesNames addObject:name];

            } else if (cell.accessoryType == UITableViewCellAccessoryCheckmark) {

                cell.accessoryType = UITableViewCellAccessoryNone;

                // Reflect deselection in data model
                [chosenEmployees removeObject:aEmployee.employeeID];
                [chosenEmployeesNames removeObject:name];
            }
        }
    }
}

更新：添加了cellForRowAtIndexPath

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

        cell.textLabel.textColor = [UIColor whiteColor];
    }

    // Get the letter in the current section
    NSString *alphabet = [charIndex objectAtIndex:[indexPath section]];

    // Get the names beginning with the letter
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", alphabet];
    NSArray *names = [listOfNames filteredArrayUsingPredicate:predicate];

    if([names count] > 0)
    {
        // Extract the name
        cell.textLabel.text = [names objectAtIndex:indexPath.row];
    }

    return cell;
}

Answer 1

我建議一個存儲NSMutableSet任一檢查ManagedObject（使用CoreData時）或者簡單地檢查IndexPaths。 In -cellForRowAtIndexPath：然后您可以檢查是否應該檢查單元格。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{
    static NSString *const identifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:identifier];
        cell.textLabel.textColor = UIColor.whiteColor;
    }

    if ([self.checkedIndexPaths containsObject:indexPath]) {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    }
    else {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *const cell = [tableView cellForRowAtIndexPath:indexPath];
    [table deselectRowAtIndexPath:indexPath animated:NO];

    if ([self.checkedIndexPaths containsObject:indexPath]) {
        [self.checkedIndexPaths removeObject:indexPath];
        cell.accessoryType = UITableViewCellAccessoryNone;
    }
    else {
        [self.checkedIndexPaths addObject:indexPath];
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    }
}

Answer 2

由於單元格正在重復使用，因此需要在cellForRowAtInexPath表數據源方法中為表格中的每個單元格設置附件標記為on或off。

因此，cell.accessoryType單元格屬性應該在cellForRowAtInexPath而不是didSelectRow委托方法中被標記。

在didSelectRow中，只需跟蹤數組中的選定行，並將單元格附件標記設置為none，或者根據數組值選中cellForRowAtInexPath中的標記。