利用长按手势实现cell移动

• 利用长按手势移动 Table View Cells
  • github

核心代码

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return UITableViewCellEditingStyleDelete;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    [self.objects removeObjectAtIndex:indexPath.row];

    [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}



- (IBAction)longPressGestureRecognized:(id)sender {

  UILongPressGestureRecognizer *longPress = (UILongPressGestureRecognizer *)sender;
  UIGestureRecognizerState state = longPress.state;

  CGPoint location = [longPress locationInView:self.tableView];
  NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];

  static UIView       *snapshot = nil;        ///< A snapshot of the row user is moving.
  static NSIndexPath  *sourceIndexPath = nil; ///< Initial index path, where gesture begins.

  switch (state) {
    case UIGestureRecognizerStateBegan: {
      if (indexPath) {
        sourceIndexPath = indexPath;

        UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];

        // Take a snapshot of the selected row using helper method.
        snapshot = [self customSnapshoFromView:cell];

        // Add the snapshot as subview, centered at cell's center...
        __block CGPoint center = cell.center;
        snapshot.center = center;
        snapshot.alpha = 0.0;
        [self.tableView addSubview:snapshot];
        [UIView animateWithDuration:0.25 animations:^{

          // Offset for gesture location.
          center.y = location.y;
          snapshot.center = center;
          snapshot.transform = CGAffineTransformMakeScale(1.05, 1.05);
          snapshot.alpha = 0.98;
          cell.alpha = 0.0;

        } completion:^(BOOL finished) {

          cell.hidden = YES;

        }];
      }
      break;
    }

    case UIGestureRecognizerStateChanged: {
      CGPoint center = snapshot.center;
      center.y = location.y;
      snapshot.center = center;

      // Is destination valid and is it different from source?
      if (indexPath && ![indexPath isEqual:sourceIndexPath]) {

        // ... update data source.
        [self.objects exchangeObjectAtIndex:indexPath.row withObjectAtIndex:sourceIndexPath.row];

        // ... move the rows.
        [self.tableView moveRowAtIndexPath:sourceIndexPath toIndexPath:indexPath];

        // ... and update source so it is in sync with UI changes.
        sourceIndexPath = indexPath;
      }
      break;
    }

    default: {
      // Clean up.
      UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:sourceIndexPath];
      cell.hidden = NO;
      cell.alpha = 0.0;

      [UIView animateWithDuration:0.25 animations:^{

        snapshot.center = cell.center;
        snapshot.transform = CGAffineTransformIdentity;
        snapshot.alpha = 0.0;
        cell.alpha = 1.0;

      } completion:^(BOOL finished) {

        sourceIndexPath = nil;
        [snapshot removeFromSuperview];
        snapshot = nil;

      }];

      break;
    }
  }
}

#pragma mark - Helper methods

/** @brief Returns a customized snapshot of a given view. */
- (UIView *)customSnapshoFromView:(UIView *)inputView {

  // Make an image from the input view.
  UIGraphicsBeginImageContextWithOptions(inputView.bounds.size, NO, 0);
  [inputView.layer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  // Create an image view.
  UIView *snapshot = [[UIImageView alloc] initWithImage:image];
  snapshot.layer.masksToBounds = NO;
  snapshot.layer.cornerRadius = 0.0;
  snapshot.layer.shadowOffset = CGSizeMake(-5.0, 0.0);
  snapshot.layer.shadowRadius = 5.0;
  snapshot.layer.shadowOpacity = 0.4;

  return snapshot;
}