Set checkmark in UITableView [duplicate]

问题:

This question already has an answer here:

TableView Cell reuse and unwanted checkmarks - this is killing me (1 answer)

Closed 6 years ago.

I'm trying to set checkmark in rows which are selected in UITableView (placed in popup view). Actually I have something like this:

-(NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{
    // Check if current row is selected
    Boolean isNowChecked = NO;
    if([self.tableView cellForRowAtIndexPath:indexPath].accessoryType == UITableViewCellAccessoryCheckmark) 
    {
        isNowChecked = YES;
    }

    if(isNowChecked) 
    {
        [self.tableView cellForRowAtIndexPath:indexPath].accessoryType = UITableViewCellAccessoryNone;
    }
    else 
    {
        [self.tableView cellForRowAtIndexPath:indexPath].accessoryType = UITableViewCellAccessoryCheckmark;
    }
    return indexPath;
}

In result I'm able to select rows, for example I touch first item then I see checkmark. When I scroll down my table view, then I see that I have check also other items (number 17, 32). When I uncheck my first item, then every check also disappear.

Do you have any suggestions what could be reason of this situation, and how can I avoid it?

回答1:

// Try this //in .h

NSMutableArray *arr_fortable;

//in .m

- (void)viewDidLoad
{
    [super viewDidLoad];

    arr_fortable = [[NSMutableArray alloc] init];
    for (int i =0; i<5; i++)
    {
        NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
        [dict setObject:[NSString stringWithFormat:@"%d",i+1] forKey:@"data"];
        [dict setObject:@"0" forKey:@"checkmark"];
        [arr_fortable addObject:dict];
    }
}


- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return [arr_fortable count];
}

- (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];
    }

    // Configure the cell...
    cell.textLabel.text = [[arr_fortable objectAtIndex:indexPath.row] objectForKey:@"data"];
    if ([[[arr_fortable objectAtIndex:indexPath.row] objectForKey:@"checkmark"] integerValue] == 1)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    }
    else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if ([[[arr_fortable objectAtIndex:indexPath.row] objectForKey:@"checkmark"] integerValue] == 1)
    {
        [[arr_fortable objectAtIndex:indexPath.row] setObject:@"0" forKey:@"checkmark"];
    }
    else
    {
        [[arr_fortable objectAtIndex:indexPath.row] setObject:@"1" forKey:@"checkmark"];
    }
    [self.tableView reloadData];
}

回答2:

see this..

tableView:didSelectRowAtIndexPath: and update which data is checked in tableView:cellForRowAtIndexPath: like this:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    // do usual stuff here including getting the cell

    // determine the data from the IndexPath.row

    if (data == self.checkedData)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    } else {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    // determine the selected data from the IndexPath.row

    if (data != self.checkedData) {
       self.checkedData = data;
    }

    [tableView reloadData];
}