如何在UITableView中移动没有NSIndexPath的单元格？

Question

I am going to move a cell from a section to another in UITableView. The problem is that I don't know the index path of this cell. (Or in other words, I have an index path for this cell but the index path is likely out of date now). Instead, I have a reference point to this cell. How can I move this cell?

thanks in advance.

Answer 1

If you have a reference to the cell's object then you can simply get its indexpath.

UITableViewCell *cellObject; //provided that you have a reference to it.
NSIndexPath *indexPath = [tableView indexPathForCell:cellObject];
[tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];

Answer 2

Here is an example of how to move a row based on finding a certain string in the cell to the top of section 1.

@implementation TableController {
    NSInteger selectedRow;
    NSMutableArray *theData;
}

-(void)viewDidLoad {
    [super viewDidLoad];
    self.tableView.contentInset = UIEdgeInsetsMake(70, 0, 0, 0);
    NSMutableArray *colors = [@[@"Black", @"Brown", @"Red", @"Orange", @"Yellow",@"Green", @"Blue"] mutableCopy];
    NSMutableArray *nums = [@[@"One", @"Two", @"Three", @"Four", @"Five", @"Six", @"Seven", @"Eight"] mutableCopy];
    theData = [@[colors, nums] mutableCopy];
}

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return theData.count;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [theData[section] count];
}

-(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    return (section == 0)? @"Colors" : @"Numbers";
}



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    cell.textLabel.text = theData[indexPath.section][indexPath.row];
    return cell;
}



-(IBAction)moveRow:(id)sender {
    NSString *objToMove = @"Red";

    // Find the section that contains "Red"
    NSInteger sectionNum = [theData indexOfObjectPassingTest:^BOOL(NSArray *obj, NSUInteger idx, BOOL *stop) {
        return [obj containsObject:objToMove];
    }];

    // Find the row that contains "Red"
    NSInteger rowNum = [theData[sectionNum] indexOfObjectIdenticalTo:objToMove];

    if (sectionNum != NSNotFound && rowNum != NSNotFound) {
        [theData[sectionNum] removeObjectIdenticalTo:objToMove];
        [theData[1] insertObject:objToMove atIndex:0];
        [self.tableView moveRowAtIndexPath:[NSIndexPath indexPathForRow:rowNum inSection:sectionNum] toIndexPath:[NSIndexPath indexPathForRow:0 inSection:1]];
    }
}