iOS長按手勢列表拖拽功能實現
專案開發中遇到拖拽功能的需求，具體要求是在編輯狀態下，首頁底部選單項可以拖動位置，便於位置切換。遇到問題後的初步想法是新增拖拽手勢，拖拽到某個位置，判斷拖拽cell的中心點是否在另一個cell內，這樣處理比較複雜，需要自己計算座標。後經一同事推薦，找到了一個更簡單的解決方案，程式碼如下。
//1、給cell新增長按手勢，在編輯狀態下可用，非編輯狀態下不可用
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
CCNewMoreMenuCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CCNewMoreMenuCellIdentifier forIndexPath:indexPath];
CCHighSeasPoolManager *seas=[CCHighSeasPoolManager sharedManager];
//新增長按手勢
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;
//編輯狀態開啟手勢
longPressGesture.enabled=YES;
}else{
[cell.btnDelete setHidden:YES];
[cell.imageDelete setHidden:YES];
[cell.btnMenu setHidden:NO];
//非編輯狀態禁用手勢
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、新增長按手勢處理方法
- (void)longPressAction:(UILongPressGestureRecognizer *)longPress {
//獲取此次點選的座標，根據座標獲取cell對應的indexPath
CGPoint point = [longPress locationInView:_collectionView];
NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:point];
//根據長按手勢的狀態進行處理。
switch (longPress.state) {
case UIGestureRecognizerStateBegan:
//當沒有點選到cell的時候不進行處理
if (!indexPath) {
break;
}
//開始移動
[self.collectionView beginInteractiveMovementForItemAtIndexPath:indexPath];
break;
case UIGestureRecognizerStateChanged:
//移動過程中更新位置座標
[self.collectionView updateInteractiveMovementTargetPosition:point];
break;
case UIGestureRecognizerStateEnded:
//停止移動呼叫此方法
[self.collectionView endInteractiveMovement];
break;
default:
//取消移動
[self.collectionView cancelInteractiveMovement];
break;
}
}
//3、監測可移動狀態
- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath {
//根據indexpath判斷單元格是否可以移動，如果都可以移動，直接就返回YES ,不能移動的返回NO
return YES;
}
//4、通過系統的移動代理，交換拖動選單項
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath
toIndexPath:(NSIndexPath *)destinationIndexPath{
CCHighSeasPoolManager *seas=[CCHighSeasPoolManager sharedManager];
[seas.dataList exchangeObjectAtIndex:sourceIndexPath.row withObjectAtIndex:destinationIndexPath.row];
}