We need some sort of automated coverage so that we can detect regressions caused by external PRs easily.

OCLint, etc

Deletion is only triggered iff the data source says its OK and the valid drag is stopped outside of all collections. As a user I may want to add a deletion area hovering over a given collection.

I propose that we change the implementation of handleDragStoppedInCollection:atPoint: to route drag handling to handleDragStoppedOutsideAtPoint:at if neither rearrange nor exchange occurs, instead of snapping back. This of course, highlights the limitation that if we stop a drag from a collection on a deletable area that also happens to be on top of the original collection, it will only be considered a delete if no rearrange occurs.

On iOS 6, if you subclass UITableViewCell or UICollectionViewCell and add subviews as properties to your custom cell they are issues with the duplicate dragging cell - the new subviews that you've added are usually not encoded/decoded for the duplicate dragging view. At present you must implement your own archiving mechanism in the subclass for your custom cell subviews.

I will provide examples on how to do this shortly.

If Src or Dst do not create duplicate views on dragging, when triggering a UITableViewCellAnimation via insertRowsAtIndexPaths, deleteRowsAtIndexPaths, etc, in the delegate method the dragging view (the original cell view object) is translated back to its previous parent and then animates.

To fix this: create duplicate views and hide the original one in the helper.

Methods in the framework should use NSParameterAssert and NSAssert to verify preconditions / postconditions.

... should I assert invariants?

I3DragArea has strong references both to the superview and an ordered set of strong references to the collections - need to investigate whether this causes retain cycles

The lack of sample implementation code make it more time consuming to evaluate your solution. Providing it will reduce barriers to us it and could increase adoption.

there is an issue with type casting to BOOL

e.g.

    BOOL isExchangable = (BOOL)cell;

-(BOOL) startDragFromView:(UIView*) container atPoint:(CGPoint) point makeCopy:(BOOL) makeCopy{


    UIView* cell;
    NSIndexPath* index = [self determineIndexForContainer:container
                                                  atPoint:point
                                                  forCell:&cell];
    DLog(@"index = %@, cell = %@", index, cell);

    BOOL isDraggable = (BOOL)cell;

    DLog(@"isDraggable = %i, %i, %i", isDraggable, !!cell, (cell != nil));

I've got result

2013-11-28 11:34:25.039 Templater[1104:c07] -[I3DragBetweenHelper startDragFromView:atPoint:makeCopy:] [Line 183] index = <NSIndexPath 0x947ccc0> 2 indexes [0, 6], cell = <BTBannerModuleCell: 0x9074b00; baseClass = UICollectionViewCell; frame = (50 1106; 280 179); gestureRecognizers = <NSArray: 0x90795b0>; layer = <CALayer: 0x90788a0>>
2013-11-28 11:34:25.039 Templater[1104:c07] -[I3DragBetweenHelper startDragFromView:atPoint:makeCopy:] [Line 187] isDraggable = 0, 1, 1
2013-11-28 11:34:25.039 Templater[1104:c07] -[I3DragBetweenHelper startDragFromView:atPoint:makeCopy:] [Line 196] isDraggable = 0
2013-11-28 11:34:25.040 Templater[1104:c07] -[I3DragBetweenHelper startDragFromView:atPoint:makeCopy:] [Line 200] Invalid Cell or Cell not Draggable.

so all (BOOL)cell should be replaced with (cell != nil) or !!cell

http://stackoverflow.com/questions/7123743/objective-c-result-of-casting-id-to-bool

Currently, rearrange swaps the drag indexPath with the drop indexPath. It would be useful if the DnD could be optionally configured to just reorder the all indexPaths above the drop by -1.

To... BetweenKit !

This is a pretty premature ticket as there are lots of issues to sort, but it would be cool if in the future we supported normal views as 'container's and their subviews as 'draggables', not just tables, collections and cells.

See closing comment on #41.

• At the moment data source methods are called with CGPoint parameters.
• These point params are often localised to different views in the arena
• Document how they are localised individually for each method - offer some tips as to how you might want to convert the points to perform various checks / operations

I3DragArea has strong references both to the superview and an ordered set of strong references to the collections. Might cause retain cycles.

The basic render delegate unhides the source item view before the dragging view has been completely snapped back. The result is a transition that doesn't look entirely convincing...

Including xcuserdata and DS_STORE files.

hidesItemWhileDraggingAtPoint:(CGPoint) at inCollection:(id<I3Collection>) collection is used by the basic render delegate to determine whether an item at a given point should be hidden whilst dragging. The questions as to whether we should hide the dragging item or not is really the responsibility of the render delegate to answer, not the data source. A user could easily implement a render delegate to just ignore this method completely; its a bit redundant.

Having said that, if we completely removed it how would one go about specifying different cells in a collection to be hidden / remain visible ?

• Fontawesome license

Is it possible to edit a UITableViewCell (swipe from right to left) to see the delete button, when i3dnd is active and dragging isn't allowed for the cell?

Would be nice to have a 'manager' class responsible for abstracting away all the boilerplate of setting up and configuring between components.

At the moment, it creates a gesture recognizer and attaches it to the superview 'behind the scenes', which causes issues if you have mutilple helpers acting on one superview as they all implicitly set its gesture recognizer.

What would be great is if we could configure a gesture recognizer outside if this class and inject it so that we can use lots of these helpers to express relations between tables/collections without causing conflict.

Its only an idea at the moment but this will make it easier to build drag and drop relations between lots of tables in the future.

As the delegate protocol does not include a parameter for the helper class that sent the delegate message, there is no way of implementing delegates for multiple helpers in a single class. Here is an example of what we need:

-(void) dragFromDstAtIndex:(NSIndexPath*) from toSrcAtIndex:(NSIndexPath*) to fromHelper:(I3DragBetweenHelper*) sender{

    if(sender == self.helper1){

       // Helper 1 impl
    }
    else if(sender == self.helper2){

      // Helper 2 impl
    }

}

...vs what we have at the moment:

-(void) dragFromDstAtIndex:(NSIndexPath*) from toSrcAtIndex:(NSIndexPath*) to{

    // How can I tell if this message was sent form helper1 or helper2?
}

This is currently being implemented in the delegate-refactor branch

I might be able to leverage your work, but I don't want to dig through your code to see how to get it running.

Any way to include a simple implementation example to allow for quick review of your solution? It would remove a barrier to adoption.

Hello,

In (UIView_) copyOfView:(UIView_) viewToCopy function
{
...

NSData* viewCopyData = [NSKeyedArchiver archivedDataWithRootObject:viewToCopy];
    UIView* viewCopy = [NSKeyedUnarchiver unarchiveObjectWithData:viewCopyData];

...
}
, i am having this issue: " [NSKeyedUnarchiver decodeBoolForKey:]: value for key (UIHighlighted) is not a boolean' "....
Its happening when i DOUBLE TAP on my item AND THEN try TO DRAG

After little research, some people fixed the problem with unsetting Highlighted but its not working for me....

Please, how i have to implement some double Tap function for ignoring double tap.

NSIndexPath is a much cleaner* way of providing the metadata around the items that are being drag / dropped. If we are drag/dropping between UI[Collection | Table]Views, at the moment users have to implement boilerplate code to map a given point to an index path in the drag data source. It makes sense to do the following:

• Add indexPathForItemAtPoint to I3Collection
• Change itemAtPoint to itemAtIndexPath in I3Collection
• Delegate the responsibility of mapping index paths to actual item views, out to the collection implementation
• Document and provide use cases for how users might implement an NSIndexPath category for use with their own I3Collection implementations. For example, a UIView that implements I3Collection may extend NSIndexPath to provide metadata about the position of its subviews.

Refactor the coordinator and other related classes to deal only in NSIndexPaths. Now we can adequately encapsulate the responsibility of mapping a given point to an associated data index to the collection.

*its cleaner in my opinion, because CGPoints are meant to specify exactly where the item is on the screen. NSIndexPath provides data about 'which items belong where' in a more abstract data-oriented way

While using this I3DragBetweenHelper code for rearranging rows in the same table view, app get crashed in the line (+[NSKeyedArchiver archivedDataWithRootObject:]) with exception as follows,

NSConcreteAttributedString initWithString:: nil value
SampleApp-[I3DragBetweenHelper copyOfView:]
in I3DragBetweenHelper.m on Line 163

0 CoreFoundation 0x2f277e8b exceptionPreprocess
1 libobjc.A.dylib 0x395726c7 objc_exception_throw
2 CoreFoundation 0x2f277dcd -[NSException initWithCoder:]
3 Foundation 0x2fba9f95 -[NSConcreteAttributedString initWithString:]
4 Foundation 0x2fba9e71 -[NSConcreteAttributedString initWithString:attributes:]
5 UIKit 0x31cf10e5 -[UILabel _attributedStringHasAttributesNotCoveredByPrimitives]
6 UIKit 0x31cf1475 -[UILabel encodeWithCoder:]
7 Foundation 0x2fbf2891 _encodeObject
8 Foundation 0x2fbf3a6f -[NSKeyedArchiver _encodeArrayOfObjects:forKey:]
9 Foundation 0x2fbf4045 -[NSArray(NSArray) encodeWithCoder:]
10 Foundation 0x2fbf2891 _encodeObject
11 UIKit 0x31c90151 -[UIView encodeWithCoder:]
12 Foundation 0x2fbf2891 _encodeObject
13 Foundation 0x2fbf3a6f -[NSKeyedArchiver _encodeArrayOfObjects:forKey:]
14 Foundation 0x2fbf4045 -[NSArray(NSArray) encodeWithCoder:]
15 Foundation 0x2fbf2891 _encodeObject
16 UIKit 0x31c90151 -[UIView encodeWithCoder:]
17 UIKit 0x31d41ced -[UITableViewCell encodeWithCoder:]
18 Foundation 0x2fbf2891 _encodeObject
19 Foundation 0x2fbf8cb1 +[NSKeyedArchiver archivedDataWithRootObject:]
20 SampleApp 0x00059b47 -[I3DragBetweenHelper copyOfView:] in I3DragBetweenHelper.m on Line 163
21 SampleApp 0x0005a50b -[I3DragBetweenHelper startDragFromView:atPoint:] in I3DragBetweenHelper.m on Line 346
22 SampleApp 0x0005b8bd -[I3DragBetweenHelper handleDragStartedInSrcAtPoint:] in I3DragBetweenHelper.m on Line 696
23 SampleApp 0x0005b23f -[I3DragBetweenHelper handleDragStarted:] in I3DragBetweenHelper.m on Line 583
24 SampleApp 0x0005b093 -[I3DragBetweenHelper handlePan:] in I3DragBetweenHelper.m on Line 528
25 UIKit 0x31b84171 _UIGestureRecognizerSendActions
26 UIKit 0x31a2e943 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:]
27 UIKit 0x31db9437 ___UIGestureRecognizerUpdate_block_invoke
28 UIKit 0x319f57af _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks
29 UIKit 0x319f3f13 _UIGestureRecognizerUpdate
30 UIKit 0x31a2d1b5 -[UIWindow _sendGesturesForEvent:]
31 UIKit 0x31a2cb63 -[UIWindow sendEvent:]
32 UIKit 0x31a01f59 -[UIApplication sendEvent:]
33 SampleApp 0x000989cd -[UIApplication(InstabugApplication) InstabugSendEvent:] in InstabugSession.m on Line 42
34 UIKit 0x31a00747 _UIApplicationHandleEventQueue
35 CoreFoundation 0x2f242f27 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION
36 CoreFoundation 0x2f2423ef __CFRunLoopDoSources0
37 CoreFoundation 0x2f240bdf __CFRunLoopRun
38 CoreFoundation 0x2f1ab541 CFRunLoopRunSpecific
39 CoreFoundation 0x2f1ab323 CFRunLoopRunInMode
40 GraphicsServices 0x33ee22eb GSEventRunModal
41 UIKit 0x31a621e5 UIApplicationMain
42 SampleApp 0x00068137 main in main.m on Line 16
43 libdyld.dylib 0x39a6bab7 start

Device used:
iPhone 5
OS 7.0.2

Please help on this issue.

Thanks.

Objectives

The main objective for V2 is to act upon the feedback given thus far in order to bring the codebase from just a helper class to a proper user interface framework.

• Testabillity
  • We now have active users and contributors. Automated tests will help us to review third party PRs, pick up regressions more easily, increase user confidence in the framework's stability and ultimately help standardise our maintenance approach.
  • We want all components of this framework to be coverable by unit tests. This will probably mean refactoring some core components to be more loosely coupled from UIKit in order to separate out the testable business logic.
  • For this release we will aim for 80% test coverage.
  • PRs from third parties must be covered my proper unit tests.
  • We will also endeavour to release some functional tests with the library, but unit tests are higher priority.
  • CI environment? Travis?
• Integration
  • Apple provides some drag-drop-ability (UITableViewRow moveable and editable properties). This framework needs to work alongside, and integrate with, these vendor-provided features.
  • This is so that users can start using the library in applications that use the built-in UIKit features.
• Help
  • People need more classes, provided by the framework, that help them meet their requirements.
  • Namely helpers for CoreData...
• Documentation
  • Documentation around contribution, change-logs, etc, is lacking.
  • This will help to standardise third party contributions and general development practices, as well as providing more transparency for users of the framework.

Plan

Phase 1

• Migrate the drag-n-drop routing logic into its own, isolated class
• Allow for the gesture listener to be injected to this class
• Create a manager-type class to register draggable components against and coordinate how the gesture recogniser is configured and injected
• Should fix #5, #6, #14,
• Should allow for #11
• Should pave the way for #7, #16, #22

Phase 2

• Review the plan
• #8
• #23
• #15
• #12
• #29

Phase 3

• Preview the plan
• _TODO... _

Timeframes

Currently I am aiming to dedicate 1, 8 hour day per week to this project (probably on a Sunday).

This might not be that big a deal but in my case, I don't want the tables to scroll with single touch. So I disable single finger/touch scroll and force 2 finger scrolling. This has a side effect of allowing drag in any direction to initiate the DnD.

Just do the following in viewDidLoad:
self.myLeftSideTable.panGestureRecognizer.minimumNumberOfTouches = 2;

Once I have one item in the dst table, I can DnD without issue. But am unable to add that first item with DnD. I also cannot DnD a cell so that I drop it at the bottom of the table (as the last row in the table) - maybe related?

Again, love this DnD solution. So easy to implement using your helper and example code. Kudos!

In the large majority of cases, the I3Collection will actually be a UIView of some sorts.

I think we should look at enforcing this constraint: if a I3Collection does not implement collectionView it must itself be a subclass of UIView, otherwise I3Collection must implement collectionView.

I thought it was not as intuitive to force the user to drop the first item at the very top on an empty table, so I made some mods that I think could improve the UX but I am not certain if there are any negative repercussions as I have not done extensive testing, yet, but so far it looks good. Here's what I did.

In I3DragBetweenHelper, I commented out lines 792 - 797 (if nil check on drop index)
https://github.com/ice3-software/i3-dragndrop/blob/master/Classes/I3DragBetweenHelper.m#L792

Then in the delegate method, droppedOnDstAtIndexPath:to fromSrcIndexPath:from, I check for index==nil and just create a new NSIndexPath with row set to the size of the datasource of the target table. I have to do the same in the srcTable as I did in the dstTable, obviously.

if (to == nil)
{
    to = [NSIndexPath indexPathForRow:(self.dstDataSource.count) inSection:0];
}

Hope this can make it into your sources as feature if you see it as useful.

At the moment, if the frames of the source and destination tables overlap only items from the src table are draggable in the overlapping areas. This applies even if the dst container is on-top of the src in the view hierarchy.

The implementation of exchange does not actually ever exchange. It drops.

We need to review 'append' vs 'exchange'.

We need a set of written guidelines around how to submit PRs and how to manually changes against the current 'Example App' (that is, until automated testing is in place).

See here and here

• Start dragging: are we starting drag within a specific area within an item?
• 'Exchanging': were are we dropping ? Problematic when potential drop is on a deletion area and the expected behaviour is for it to snap back

... more examples to come.

A LICENSE.txt needs to be added so that this codebase can be used accordingly.

The class uses NSLog to log regardless of the build environment. It should use its own logging macro that wraps NSLog and this should be 'turned off' in production.

Hi, nice library. I have a question: is it possible to make d'n'd between 3 tableviews?

I have followed the I32RearrangeableExchangeableTablesViewController and when I reorder it crashes. Assuming my fault but not sure where to start looking. Tried debugging but still not seeing clear root cause.

I see it stating "This view probably hasn't received initWithFrame: or initWithCoder:" but not exactly sure what that means. My app was initially implemented back in 2011, so perhaps a version issue (ARC, or something to that effect).

Here is the debugger output with error below.

If you have any insights, would be much appreciated. This is a really great time saver for me. Thanks for putting it together and making it available.

2014-03-10 17:27:38.949 Lacrosse-Stats[609:70b] Dragging from destination to destination.
2014-03-10 17:27:38.950 Lacrosse-Stats[609:70b] Rearrangeing dst
2014-03-10 17:27:42.128 Lacrosse-Stats[609:70b] *** 6) start isCellInDstAtIndexPathExchangable
2014-03-10 17:27:42.128 Lacrosse-Stats[609:70b] Cell row: 3
2014-03-10 17:27:42.144 Lacrosse-Stats[609:70b] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Requesting the window of a view (<UITableViewCell: 0xdca2e00; frame = (0 0; 0 0); transform = [0, 0, 0, 0, 0, 0]; text = '2 - Frick, Andrew'; alpha = 0; autoresize = W; layer = (null)>) with a nil layer. This view probably hasn't received initWithFrame: or initWithCoder:.'
*** First throw call stack:
(
0 CoreFoundation 0x0389b5e4 exceptionPreprocess + 180
1 libobjc.A.dylib 0x02d898b6 objc_exception_throw + 44
2 CoreFoundation 0x0389b3bb +[NSException raise:format:] + 139
3 UIKit 0x01bb2f5b __windowForView + 467
4 UIKit 0x01bb52a0 -[UIView(Hierarchy) _postMovedFromSuperview:] + 28
5 UIKit 0x01bc04c1 -[UIView(Internal) _addSubview:positioned:relativeTo:] + 1847
6 UIKit 0x01bb39b1 -[UIView(Hierarchy) addSubview:] + 56
7 Lacrosse-Stats 0x00083d2f -[I3DragBetweenHelper animateDummyExchange:inContainer:withCompletionBlock:] + 879
8 Lacrosse-Stats 0x00088467 -[I3DragBetweenHelper handleDragFromDstStoppedInDstAtPoint:] + 1031
9 Lacrosse-Stats 0x00086949 -[I3DragBetweenHelper handleDragStopped:] + 1289
10 Lacrosse-Stats 0x0008623e -[I3DragBetweenHelper handlePan:] + 254
11 UIKit 0x01ed0e8c _UIGestureRecognizerSendActions + 230
12 UIKit 0x01ecfb00 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 383
13 UIKit 0x01ed156d -[UIGestureRecognizer _delayedUpdateGesture] + 60
14 UIKit 0x01ed4acd ___UIGestureRecognizerUpdate_block_invoke + 57
15 UIKit 0x01ed4a4e _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks + 317
16 UIKit 0x01ecb148 _UIGestureRecognizerUpdate + 199
17 UIKit 0x01b9719a -[UIWindow _sendGesturesForEvent:] + 1291
18 UIKit 0x01b980ba -[UIWindow sendEvent:] + 1030
19 UIKit 0x01b6be86 -[UIApplication sendEvent:] + 242
20 UIKit 0x01b5618f _UIApplicationHandleEventQueue + 11421
21 CoreFoundation 0x0382483f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION + 15
22 CoreFoundation 0x038241cb __CFRunLoopDoSources0 + 235
23 CoreFoundation 0x0384129e __CFRunLoopRun + 910
24 CoreFoundation 0x03840ac3 CFRunLoopRunSpecific + 467
25 CoreFoundation 0x038408db CFRunLoopRunInMode + 123
26 GraphicsServices 0x037559e2 GSEventRunModal + 192
27 GraphicsServices 0x03755809 GSEventRun + 104
28 UIKit 0x01b58d3b UIApplicationMain + 1225
29 Lacrosse-Stats 0x0000300d main + 125
30 libdyld.dylib 0x03270701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

Include the following:

• I3CollectionView, UICollectionView subclass
• I3View, simple UIView subclass that allows to drag / droppings its subviews

... or, because I3Collection no longer requires a drag data source property, we can just use categories now !

See 3rd revision of the plan in comment on #28