UITableView：通过拖放将单元格移动到另一个位置

Question

i have a table with 3 section (section one, section two and section three). I would like implement a mechanism to change a cell's position with drag & drop (inside same section or from a section to another).

Example 1: In section one i have two rows (sec1_row1 and sec1_row2). In section two i have one row (sec2_row1) by drag & drop function i would like invert the sec1_row2 with sec2_row1. I would like select the sec2_row1, drag it on sec2_row1 and drop it so the rows are inverted.

I would like that this feature will be also available for rows of same section.

What is the best way to implement this feature?

Thanks in advance.

Answer 1

Check this apple doc link

https://developer.apple.com/library/ios/documentation/userexperience/conceptual/tableview_iphone/ManageReorderRow/ManageReorderRow.html

you need to manage conditions in

targetIndexPathForMoveFromRowAtIndexPath

canMoveRowAtIndexPath

Answer 2

- (NSIndexPath *)tableView:(UITableView *)tableView
    targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath *)sourceIndexPath
    toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath 
  {
      NSDictionary *section = [data objectAtIndex:sourceIndexPath.section];
      NSUInteger sectionCount = [[section valueForKey:@"content"] count];
      if (sourceIndexPath.section != proposedDestinationIndexPath.section)
      {
          NSUInteger rowInSourceSection =
          (sourceIndexPath.section > proposedDestinationIndexPath.section) ?
           0 : sectionCount - 1;
          return [NSIndexPath indexPathForRow:rowInSourceSection inSection:sourceIndexPath.section];
      } 
      else if (proposedDestinationIndexPath.row >= sectionCount) 
      {
          return [NSIndexPath indexPathForRow:sectionCount - 1 inSection:sourceIndexPath.section];
      }

     // Allow the proposed destination.
     return proposedDestinationIndexPath;
  }

For further information check below link:

Managing the Reordering of Rows

If you want to prevent re-ordering outside section then please refer this link: How to limit UITableView row reordering to a section

Answer 3

You can control the movement of rows within section and between section using below approach

- (NSIndexPath *)tableView:(UITableView *)tableView targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath *)sourceIndexPath toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath
{

    // Do not allow any movement between section
    if ( sourceIndexPath.section != proposedDestinationIndexPath.section)
        return sourceIndexPath;
    // You can even control the movement of specific row within a section. e.g last row in a     Section

    // Check if we have selected the last row in section
    if (   sourceIndexPath.row < sourceIndexPath.length) {
        return proposedDestinationIndexPath;
    } else {
        return sourceIndexPath;
    }
    // You can use this approach to implement any type of movement you desire between sections or within section    
}

Answer 4

Try this code is working fine.

 #import "ViewController.h"

    @interface ViewController ()<UITableViewDelegate,UITableViewDataSource>
    {
        NSMutableArray *NameArray;
    }

    @property (weak, nonatomic) IBOutlet UITableView *NameListTableView;
    @end

    @implementation ViewController

    - (void)viewDidLoad {
        [super viewDidLoad];

        _NameListTableView.delegate=self;
        _NameListTableView.dataSource=self;

        NameArray=[NSMutableArray arrayWithObjects:@"apple", @"b", @"c", @"d", @"e",@"f", @"g", @"h",@"i",@"j", @"k", nil];



        [self.NameListTableView setEditing:YES animated:YES];
        // Do any additional setup after loading the view, typically from a nib.
    }


    - (void)didReceiveMemoryWarning {
        [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
    }

    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
        return NameArray.count;

    }
    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
    {
        static NSString *cellId=@"NameCell";

        UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:cellId];
        if(cell!=nil)
        {
            cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellId];
        }

        NSString *abc=[NameArray objectAtIndex:indexPath.row];

        cell.textLabel.text=abc;


        return cell;


    }
    - (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
    {
        return UITableViewCellEditingStyleNone;
    }
    - (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
    {
        return YES;
    }
    - (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath *)destinationIndexPath
    {
        [NameArray exchangeObjectAtIndex:sourceIndexPath.row withObjectAtIndex:destinationIndexPath.row];

        [self.NameListTableView reloadData];
    }
    @end