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https://github.com/bauerca/drag-sort-listview

Android ListView with drag and drop reordering.
https://github.com/bauerca/drag-sort-listview

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Android ListView with drag and drop reordering.

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README 

        
DragSortListView

================



# NOTICE: No longer maintained.



I do not have much time to devote to this project so I am

dropping support for the time being. Sorry everybody!



News

----



**April 2, 2013**: Hey all. If you want to send a pull request,

please read the [Contributing](https://github.com/bauerca/drag-sort-listview#contributing) section first. Thanks!



**Feb. 9, 2013**: Version 0.6.0. Consolidated remove modes to

`click_remove` and `fling_remove`. No more fling remove while

dragging; fling anywhere on item to remove it.

[Leszek Mzyk](https://github.com/imbryk) is a bona fide code-slanger.



**Jan. 10, 2013**: Version 0.5.0 is released. Supports ListView

multi-choice and single-choice modes thanks to the hard work of

[Mattias Flodin](https://github.com/mattiasflodin)! Awesome-sauce.

Check out the new demos.



**Nov. 23, 2012**: Hmmm, what's this? → [Gittip](https://www.gittip.com/bauerca) :)



**Nov. 17, 2012**: [Drag-Sort Demos](https://play.google.com/store/apps/details?id=com.mobeta.android.demodslv)

app in Google Play Store!



**Nov. 15, 2012**: Smooth operation! Drops and removals are animated.

Also, DragSortController now provides a convenience

click-to-remove feature (see [XML attrs](https://github.com/bauerca/drag-sort-listview#xml-layout-declaration)

and [RemoveListener](https://github.com/bauerca/drag-sort-listview#dragsortlistviewremovelistener)

sections).



**Nov. 11, 2012**: Mavenized.

Thanks to [Andreas Schildbach (Goonie)](https://github.com/Goonie)!



**Oct. 30, 2012**: DragSortCursorAdapter class helps you reorder

a Cursor-backed ListAdapter. Look at ResourceDragSortCursorAdapter

and SimpleDragSortCursorAdapter as well in [the API](

http://bauerca.github.com/drag-sort-listview).



**Oct. 19, 2012**: Public API documentation is up at

http://bauerca.github.com/drag-sort-listview.



**Oct. 19, 2012**: Refactoring rampage. Backward compatibility is slightly

broken. New features make it worthwhile :) and include: total floating

View customization, total control over drag start/stop,

and a helper class implementing common patterns (long-press to drag,

fling-to-remove, etc.). Thanks to

[Dan Hulme (orac)](https://github.com/orac)

for getting all this rolling!

Check out the extensively updated demos and usage section below.



**Sept. 26, 2012**: Drag-sorting is now animated! (optional, of course)

Items slide around underneath the floating (dragged) View.



Overview

--------



DragSortListView (DSLV) is an extension of the Android ListView that enables

drag-and-drop reordering of list items. It is a ~~major overhaul~~ complete

rewrite of

the [TouchInterceptor](https://github.com/android/platform_packages_apps_music/blob/master/src/com/android/music/TouchInterceptor.java) (TI) 

meant to give drag-sorting a polished feel. Some key features are:



1. Clean drag and drop (no visual glitches; I hope!)

2. Intuitive and smooth scrolling while dragging.

3. Support for heterogeneous item heights.

4. Public `startDrag()` and `stopDrag()` methods.

5. Public interface for customizing the floating View.



DragSortListView is useful for all kinds of prioritized lists:

favorites, playlists, checklists, etc. Would love to hear about

your use case or app by email.

I hope you find it useful; and please, help me improve the thing!



Widget usage

------------



Three major elements define the drag-sort process. Roughly, in

order of importance, they are:



1. **Data reordering**. Drag-sorts reorder the data

underlying your list. Since DSLV

cannot know how you organize your data, the reordering must be

performed by you using the provided Listener interfaces.

2. **Drag start/stop**. Drags are started and stopped by

calling `startDrag()` and

`stopDrag()` on your DSLV instance; but some help that is.

The convenience class, DragSortController, provides all kinds of

boiler-plate for common start/stop/remove drag patterns.

3. **Floating View**. The floating View appearance and behavior is

controlled by an

implementation of the FloatViewManager interface. With this, you

can display any View you like as the floating View, and update its

appearance/location on every touch event. The DragSortController

helper class also implements this interface for convenience.



Number 1 is essential. As mentioned above, 2 and 3 can

be handled by the DragSortController helper class. Keep reading,

then head to the

demo and start studying some examples.



### XML layout declaration



DragSortListView can be declared in an XML layout file just like

the ListView. Several example layout files are

[provided in the demo](https://github.com/bauerca/drag-sort-listview/blob/master/demo/res/layout/).

The available attributes (in addition to the usual

ListView attributes) are given below. Read each bullet as



* ``: (``, ``) ``.



#### XML attributes



* `collapsed_height`: (dimension, 1px) Height of placeholder at original

drag position. Cannot be zero.

* `drag_scroll_start`: (float, 0.3) Start of drag-scroll regions

(defined by a

fraction of the total DSLV height; i.e. between 0 and 1).

* `max_drag_scroll_speed`: (float, 0.5) Maximum drag-scroll speed for

default linear drag-scroll profile. Units of pixels/millisecond.

* `float_alpha`: (float, 1.0) Transparency of floating View. Value from

0 to 1 where 1 is opaque.

* `slide_shuffle_speed`: (float, 0.7) Speed of shuffle animations

underneath floating View. A value

of 0 means a shuffle animation is always in progress, whereas a value

of 1 means items snap from position to position without animation.

* `drop_animation_duration`: (int, 150) Drop animation smoothly centers

  the floating View over the drop slot before destroying it. Duration

  in milliseconds.

* `remove_animation_duration`: (int, 150) Remove animation smoothly

  collapses the empty slot when an item is removed. Duration

  in milliseconds.

* `track_drag_sort`: (bool, false) Debugging option; explained below.

* `use_default_controller`: (bool, true) Have DSLV create a

  DragSortController instance and pass the following xml attributes

  to it. If you set this to false, ignore the following attributes.

* `float_background_color`: (color, BLACK) Set the background

  color of the floating View when using the default

  DragSortController. Floating View in this case is a snapshot of

  the list item to be dragged.

* `drag_handle_id`: (id, 0) Android resource id that points to a

  child View of a list item (or the root View of the list item

  layout). This identifies the "drag handle," or the View within a

  list item that must

  be touched to start a drag-sort of that item.

  Required if drags are to be enabled using the default

  DragSortController.

* `sort_enabled`: (bool, true) Enable sorting of dragged item (disabling

  is useful when you only want item removal).

* `drag_start_mode`: (enum, "onDown") Sets the gesture for starting

  a drag.

    + "onDown": Drag starts when finger touches down

      on the drag handle.

    + "onDrag": Drag starts when finger touches down on drag handle

      and then drags (allows item clicks and long clicks).

    + "onLongPress": Drag starts on drag handle long press (allows

      item clicks).

* `remove_enabled`: (bool, false) Enable dragged item removal by one

  of the `remove_mode` options below.

* `remove_mode`: (enum, "flingRight") Sets the gesture for removing the

  dragged item.

    + "clickRemove": Click on item child View with id `click_remove_id`.

    + "flingRemove": Fling horizontal anywhere on item.

* `click_remove_id`: (id, 0) Android resource id that points to a

  child View of a list item. When `remove_mode="clickRemove"` and

  `remove_enabled="true"`, a click on this child View removes the

  containing item. This attr is used by DragSortController.

* `fling_handle_id`: (id, 0) Android resource id that points to a

  child View of a list item. When `remove_mode="flingRemove"` and

  `remove_enabled="true"`, a fling that originates on this child

  View removes the containing item. This attr is used by

  DragSortController.



### Listeners



DragSortListView is a ListView, and thus requires a [ListAdapter](http://developer.android.com/reference/android/widget/ListAdapter.html)

to populate

its items. Drag-sorting additionally implies a reordering of the items

in the ListAdapter, achieved through callbacks to special Listener

interfaces

defined in DSLV. Listeners can be registered with DSLV in two ways:



1. Pass them individually to the `set*Listener()` methods

2. Implement the Listener interfaces you require in a custom

ListAdapter; when `DragSortListView.setAdapter()` is called

with your custom

Adapter, DSLV detects which interfaces are implemented and calls

the appropriate `set*Listener()` methods on itself with the

provided ListAdapter as argument.



Each Listener interface is described below:



#### DragSortListView.DropListener



The DropListener interface has a single callback:

```java

public void drop(int from, int to);

```

This is called upon completion of the drag-sort; i.e. when the

floating View is dropped.

The parameter `from` is the ListView item that was originally dragged,

and `to` is the position where the item was dropped.

This is an important callback; without

a DropListener, DSLV is for all practical purposes useless.



For proper DSLV operation, this callback must perform

a reordering of the data in your ListAdapter. For example, one often

has a Cursor that pulls from a database and backs a

CursorAdapter. The order of items in the

Cursor is fixed; therefore, given drag-sorting, you must implement

a mapping from Cursor positions to DSLV positions. This is commonly

done

within in a custom ListAdapter or CursorWrapper that implements the

DropListener interface. See Issue #20 for a discussion of this.

**Update**: Or simply use the DragSortCursorAdapter class!



If your DSLV instance `android:choiceMode` is not `"none"`, and your

ListAdapter does not have stable ids, you must call

[DragSortListView.moveCheckState(int from, int to)](http://bauerca.github.com/drag-sort-listview/reference/com/mobeta/android/dslv/DragSortListView.html#moveCheckState(int, int\))

within `drop(from, to)`. See the documentation in the DSLV API for more

info.



#### DragSortListView.RemoveListener



As the TI did, DSLV provides gestures for removing the floating

View (and its associated list item) from the list. Upon completion of

a remove gesture, DSLV calls the RemoveListener method:

```java

public void remove(int which);

```

The position `which` should be "removed" from your ListAdapter; i.e.

the mapping from your data (e.g. in a Cursor) to your ListAdapter

should henceforth neglect the item previously pointed to by `which`.

Whether you actually remove the data or not is up to you.



Item removal can now happen outside of a drag event. The method

`DragSortListView.removeItem(int position)` can be called at any time.



If your DSLV instance `android:choiceMode` is not `"none"`, and your

ListAdapter does not have stable ids, you must call

[DragSortListView.removeCheckState(int position)](http://bauerca.github.com/drag-sort-listview/reference/com/mobeta/android/dslv/DragSortListView.html#removeCheckState(int\))

within `remove(which)`. See the documentation in the DSLV API for more

info.



#### DragSortListView.DragListener



The callback in the DragListener is

```java

public void drag(int from, int to);

```

This is called whenever the floating View hovers to a new potential

drop position; `to` is the current potential drop position, and `from` is

the previous one. The TI provided this callback; an example of usage

does not come to mind.



#### DragSortListView.DragSortListener



This is a convenience interface which combines all of the above

Listener interfaces.



### FloatViewManager



This is the interface that handles creation, updates, and tear-downs

of the floating View. It is passed to DSLV using the

`setFloatViewManager()` method. Example usage can be found in

the SimpleFloatViewManager, which

is a convenience class

that simply takes a snapshot of the list item to be dragged.



If you want to spice up the floating View, implement your own

FloatViewManager. In your

`onCreateFloatView()` method, you should make sure that the View

you return has a definite height (do not use MATCH_PARENT! although

MATCH_PARENT is perfectly okay for the layout width).

DSLV will measure and layout your floating View according to

the ViewGroup.LayoutParams attached to it. If no LayoutParams are

attached, DSLV will use WRAP_CONTENT and MATCH_PARENT as the layout

height and width.



### Drag start/stop



As of DragSortListView 0.3.0, drag start and stop behavior is all up

to you. Feel free to call `startDrag()` or `stopDrag()` on the

DSLV instance whenever you please. Be aware that if no

touch event is in progress when `startDrag()` is called, the drag will

not start. But don't waste too much time working on your own drag

initiation if it's simple; the DragSortController described below

will do that for you.



### DragSortController



The DragSortController

is a convenience class that implements some common

design patterns for initiating drags or removing the dragged item

from the list. It implements

the View.OnTouchListener interface to watch touch events as they are

dispatched to DSLV. It also implements the FloatViewManager interface

(by subclassing SimpleFloatViewManager) to handle simple floating View

creation. If you do not use XML to create

the default DragSortController, you must pass in your own

instance of DragSortController

to both the `setFloatViewManager()` *and* `setOnTouchListener()`

methods of the DSLV instance.



The default behavior of the DragSortController expects list items

that are drag enabled to have a child View called a "drag handle."

The drag handle View should have an associated android resource id,

and that id should

be passed into the DragSortController (the id can be set in XML if

`use_default_controller` is `true`). If a touch event lands on the

drag handle of an item, and a gesture is detected that should start a

drag, the drag starts.



Additional documentation

------------------------



There is limited documentation in the DSLV.

You can check it

out with Javadoc by navigating to `/path/to/drag-sort-listview/src/` and

typing



    javadoc com.mobeta.android.dslv *



The javadoc can be viewed on the DSLV project page:

http://bauerca.github.com/drag-sort-listview. Sorry for the many

broken links at the moment. I am slowly getting to this.



Installation

------------



Download and install the [Android sdk](http://developer.android.com/sdk/index.html). Clone/Download/Fork the repo

through GitHub or via (read-only)



    git clone https://github.com/bauerca/drag-sort-listview.git



### Ant



Execute the following in both the drag-sort-listview/library/ and

drag-sort-listview/demo/ directories (assuming

/path/to/android_sdk/tools is in your PATH):



    android update project --path ./



To test out the demo, navigate to drag-sort-listview/demo/ and

execute



    ant debug install



to build and install the demo on your connected device/emulator.



### Maven



A simple



    mvn clean install



should suffice to build and put the DSLV lib and demo in your local

maven repository. To include in your project, add the following

dependency to your pom.xml:



```xml



    com.mobeta.android.dslv

    drag-sort-listview

    0.6.1-SNAPSHOT

    apklib



```



### Installation in Eclipse (Indigo)



The first step is to choose File > Import or right-click in the Project Explorer

and choose Import. If you don't use E-Git to integrate Eclipse with Git, skip

the rest of this paragraph. Choose "Projects from Git" as the import source.

From the Git page, click Clone, and enter the URI of this repository. That's the

only text box to fill in on that page. On the following pages, choose which

branches to clone (probably all of them) and where to keep the local checkout,

and then click Finish. Once the clone has finished, pick your new repository

from the list, and on the following page select 'Use the New Projects wizard'.



From here the process is the same even if you don't use E-Git. Choose 'Android

Project from Existing Code' and then browse to where you checked out DSLV. You

should then see two projects in the list: one named after the directory name,

and the other called com.mobeta.android.demodslv.Launcher . The top one is the

library project, and the bottom one the demo project. You probably want both at

first, so just click Finish.



Finally, to add the library to your application project, right-click your

project in the Package Explorer and select Properties. Pick the "Android" page,

and click "Add..." from the bottom half. You should see a list including the

DSLV project as well as any others in your workspace.



Contributing

------------



First of all, thank you! Many of your pull requests have added

tremendous value to this project. Your efforts are truly appreciated!



Now that the project is fairly mature, I would like to lay out

some (loose) rules for future pull requests. So far I have

only one (of course, you should help me add more). Here's the list:



* Avoid pull requests that are small tweaks to default

  DragSortController behavior. This class is merely a guide/helper

  for creating more complex drag-sort interactions. For example,

  if you don't

  like the feel of the default fling-remove initiation for your

  app, then you should not create a pull request that "fixes"

  the behavior. Rather, try to modify or subclass DragSortController

  for your particular needs. That said, if a "must-have" touch

  pattern arises, I think there is some wiggle room in this rule.



Debugging

---------



If you have python and [matplotlib](http://matplotlib.sourceforge.net/)

installed, you can use the script dslv.py

to debug drag-sort behavior. This script

is found in the project tools/ directory.



To enable, just set the `dslv:track_drag_sort` attribute to

`"true"` in XML. While drag-sorting on your emulator or device,

this tracking causes the DSLV to periodically dump its state to

a file called dslv_state.txt in the device/emulator /sdcard/ directory. 



Navigate to the location of dslv.py, and do 



    adb [-e|-d|-s device] pull /sdcard/dslv_state.txt



then simply run



    python dslv.py



An image should appear that represents the DSLV in the final

recorded state. Right and left keys allow stepping

through the recorded drag-sort frame-by-frame; up/down keys jump

30 frames. This tool has

been very useful for debugging jumpy behavior while drag-scrolling.



License

-------



```

A subclass of the Android ListView component that enables drag

and drop re-ordering of list items.



Copyright 2012 Carl Bauer



Licensed under the Apache License, Version 2.0 (the "License");

you may not use this file except in compliance with the License.

You may obtain a copy of the License at



    http://www.apache.org/licenses/LICENSE-2.0



Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

```