iOS长按手势列表拖拽功能实现

项目开发中遇到拖拽功能的需求，具体要求是在编辑状态下，首页底部菜单项可以拖动位置，便于位置切换。遇到问题后的初步想法是添加拖拽手势，拖拽到某个位置，判断拖拽cell的中心点是否在另一个cell内，这样处理比较复杂，需要自己计算坐标。后经一同事推荐，找到了一个更简单的解决方案，代码如下。

//1、给cell添加长按手势，在编辑状态下可用，非编辑状态下不可用

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{

CCNewMoreMenuCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CCNewMoreMenuCellIdentifier forIndexPath:indexPath];

CCHighSeasPoolManager *seas=[CCHighSeasPoolManager sharedManager];

//添加长按手势

UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAction:)];

[cell addGestureRecognizer:longPressGesture];

if (seas.isEdit) {

    [cell.btnDelete setHidden:NO];

    [cell.imageDelete setHidden:NO];

    [cell.btnMenu setHidden:YES];

    longPressGesture.cancelsTouchesInView=YES;

    //编辑状态开启手势

    longPressGesture.enabled=YES;

}else{

    [cell.btnDelete setHidden:YES];

    [cell.imageDelete setHidden:YES];

    [cell.btnMenu setHidden:NO];

    //非编辑状态禁用手势

    longPressGesture.enabled=NO;

}

[cell.btnMenu addTarget:self action:@selector(btnMenuAction:) forControlEvents:UIControlEventTouchDown];

cell.btnMenu.btnRow=indexPath.item;

[cell.btnDelete addTarget:self action:@selector(btnDeleteAction:) forControlEvents:UIControlEventTouchDown];

cell.btnDelete.btnRow=indexPath.item;

CCMoreListModel *model = [seas.dataList objectAtIndex:indexPath.item];

cell.headerModel=model;

return cell;

}

//2、添加长按手势处理方法

• (void)longPressAction:(UILongPressGestureRecognizer *)longPress {

  //获取此次点击的坐标，根据坐标获取cell对应的indexPath

  CGPoint point = [longPress locationInView:_collectionView];

  NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:point];

  //根据长按手势的状态进行处理。

  switch (longPress.state) {

    case UIGestureRecognizerStateBegan:
  
        //当没有点击到cell的时候不进行处理
  
        if (!indexPath) {
  
            break;
  
        }
  
        //开始移动
  
        [self.collectionView beginInteractiveMovementForItemAtIndexPath:indexPath];
  
        break;
  
    case UIGestureRecognizerStateChanged:
  
    //移动过程中更新位置坐标
  
        [self.collectionView updateInteractiveMovementTargetPosition:point];
  
        break;
  
    case UIGestureRecognizerStateEnded:
  
    //停止移动调用此方法
  
        [self.collectionView endInteractiveMovement];
  
        break;
  
    default:
  
    //取消移动
  
        [self.collectionView cancelInteractiveMovement];
  
        break;
  

  }

}

//3、监测可移动状态

• (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath {

    //根据indexpath判断单元格是否可以移动，如果都可以移动，直接就返回YES ,不能移动的返回NO
  
    return YES;
  

}

//4、通过系统的移动代理，交换拖动菜单项

• (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath

       toIndexPath:(NSIndexPath *)destinationIndexPath{
  

  CCHighSeasPoolManager *seas=[CCHighSeasPoolManager sharedManager];

  [seas.dataList exchangeObjectAtIndex:sourceIndexPath.row withObjectAtIndex:destinationIndexPath.row];

}