如何启用滑动以删除TableView中的单元格？

Question

I have a UIViewController that implements TableViews delegate and datasource protocols. Now I want to add "swipe to delete" gesture to cells.

How should I go about it.

I have given a blank implementation of commitEditingStyle method and also set the Editing property to YES.

Still the swipe feature is not coming .

Now Do I need to separately add UISwipeGesture to each cell ?

Or am I missing something ?

Answer 1

As Dan has commented above, you need to implement the following table view delegate methods:

1. tableView:canEditRowAtIndexPath:
2. tableView:commitEditingStyle:forRowAtIndexPath:

Note: I have tried this in iOS 6 and iOS 7.

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return YES - we will be able to delete all rows
    return YES;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Perform the real delete action here. Note: you may need to check editing style
    //   if you do not perform delete only.
    NSLog(@"Deleted row.");
}

Answer 2

You don't have to set editing:YES if you need to show Delete button on cell swipe. You have to implement tableView:canEditRowAtIndexPath: and return YES from there for rows you need to edit/delete. This is not necessary when your tableView's dataSource is a subclass of UITableViewContoller - this method, if not overridden, returns YES by default. In all other cases you have to implement it.

EDIT: Together we have found the problem - tableView:editingStyleForRowAtIndexPath: returned UITableViewCellEditingStyleNone if table wasn't in editing mode.

Answer 3

// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return YES;
}



// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    }   
    else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }   
}

Answer 4

Please try this code in swift,

override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
   // let the controller to know that able to edit tableView's row 
   return true
}

override func tableView(tableView: UITableView, commitEditingStyle editingStyle UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath)  {
   // if you want to apply with iOS 8 or earlier version you must add this function too. (just left in blank code)
}

override func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]?  {
   // add the action button you want to show when swiping on tableView's cell , in this case add the delete button.
   let deleteAction = UITableViewRowAction(style: .Default, title: "Delete", handler: { (action , indexPath) -> Void in

   // Your delete code here.....
   .........
   .........
   })

   // You can set its properties like normal button
   deleteAction.backgroundColor = UIColor.redColor()

   return [deleteAction]
}

Answer 5

Try adding the following to your class:

// Override to support conditional editing of the table view.
- (BOOL) tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    return(YES);
}

Answer 6

Conclusion of Kyr Dunenkoff chat is

- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath {

}

should not be defined if you need delete button to appear on swipe.

Answer 7

If you are using an NSFetchedResultsControllerDelegate to populate the table view, this worked for me:

• Make sure tableView:canEditRowAtIndexPath returns true always

• In your tableView:commitEditingStyle:forRowAtIndexPath implementation, do not delete the row directly from the table view. Instead, delete it using your managed object context, eg:

   if editingStyle == UITableViewCellEditingStyle.Delete { let word = self.fetchedResultsController.objectAtIndexPath(indexPath) as! Word self.managedObjectContext.deleteObject(word) self.saveManagedObjectContext() } func saveManagedObjectContext() { do { try self.managedObjectContext.save() } catch { let saveError = error as NSError print("\\(saveError), \\(saveError.userInfo)") } } 

Answer 8

This was a problem for me too...I could only get swiping to delete to work once every 10 or so attempts. It turns out the gesture on the TV was being blocked by another gesture in the parent view controller. The TV was nested in a MMDrawerController (swipe able drawer layout).

Just configuring the gesture recognizer in the drawer controller to not respond to close gestures in the flanking drawers allowed swipe to delete to work in my TV.

You could also try doing something like this with the gesture delegate :

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES;
}

Answer 9

This is the swift version

// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
    // Return NO if you do not want the specified item to be editable.
    return true
}

// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
    if editingStyle == .Delete {
        // Delete the row from the data source
        tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    } else if editingStyle == .Insert {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }    
}

Answer 10

根据我的经验，您似乎必须将UITableView editing设置为NO才能滑动才能工作。

self.tableView.editing = NO;

Answer 11

在iOS 8.0之后，您可以自定义您的操作

- (nullable NSArray<UITableViewRowAction *> *)tableView:(UITableView *)tableView editActionsForRowAtIndexPath:(NSIndexPath *)indexPath

Answer 12

NSMutableArray *post= [NSMutableArray alloc]initWithObject:@"1",@"2",@"3",nil]; 


- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView 
           editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath {

    NSUInteger row = [indexPath row];
    NSUInteger count = [posts count];

    if (row < count) {
        return UITableViewCellEditingStyleDelete;
    } else {
        return UITableViewCellEditingStyleNone;
    }
}

- (void)tableView:(UITableView *)tableView 
                    commitEditingStyle:(UITableViewCellEditingStyle)editingStyle
                    forRowAtIndexPath:(NSIndexPath *)indexPath {

    NSUInteger row = [indexPath row];
    NSUInteger count = [posts count];

    if (row < count) {

        [posts removeObjectAtIndex:row];
    }
}

Answer 13

You can see all necessary methods by creating a UITableViewController class (temporary) in XCode 5 and then copy which method you would like to use. Those methods you need will be commented out with pre-filled in lines you desire.