DragNDropList

An easy to use Drag & Drop List for Android. Direct replacement of the android ListView.

Code Quality Rank: L3

Programming language: Java

License: Apache License 2.0

Tags: ListView/ScrollView Widget    

README

DragNDropListView

DragNDropListView is a direct replacement for the stock Android ListView. If you know how to use ListView, you already know how to use DragNDropListView. All you have to do is replace ListView and SimpleCursorAdapter/SimpleAdapter with DragNDropListView and its adapters.

Usage

DragNDropListView is an Android Library project. If you use Eclipse do the following.

• Clone git clone git://github.com/terlici/DragNDropList.git
• Import it in Eclipse
• Add DragNDropList as a library to your Android project

Layout

A common layout for list view is the following:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ListView
        android:id="@id/android:list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</LinearLayout>

Just replace ListView with com.terlici.dragndroplist.DragNDropListView:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.terlici.dragndroplist.DragNDropListView
        android:id="@id/android:list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</LinearLayout>

Row Layout

In DragNDropListView each item has a drag handler, which the users touch to drag the item around.

Here is a common layout for each row. It contains an image of a star and some text. The user can reorder the items by touching the star of an item and dragging it around.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="80px"
    android:orientation="horizontal"
    android:gravity="center_vertical"
    >

    <ImageView
        android:id="@+id/handler"
        android:layout_width="60px"
        android:layout_height="60px"
        android:src="@android:drawable/btn_star_big_on"
        android:layout_marginLeft="8px"
        />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

Loading DragNDropListView

This is the usual way to load a ListView:

ListView list = (ListView)findViewById(android.R.id.list);

SimpleCursorAdapter adapter = new SimpleCursorAdapter(context,
                        R.layout.row,
                        cursor,
                        new String[]{"text"},
                        new int[]{R.id.text},
                        0);

list.setListAdapter(adapter);

When using DragNDropListView just replace ListView with DragNDropListView, SimpleCursorAdapter with DragNDropCursorAdapter and set the id of the drag handler as the last parameter of the adapter. In the row layout above this will be R.id.handler. Last, instead of setListAdapter use setDragNDropAdapter.

DragNDropListView list = (DragNDropListView)findViewById(android.R.id.list);

DragNDropCursorAdapter adapter = new DragNDropCursorAdapter(context,
                           R.layout.row,
                           cursor,
                           new String[]{"text"},
                           new int[]{R.id.text},
                           R.id.handler);

list.setDragNDropAdapter(adapter);

You are done! As you see there is very little to change to your existing code.

Events

DragNDropListView provides an event listener for drag and drop.

list.setOnItemDragNDropListener(...)

The interface for this listener is:

public interface OnItemDragNDropListener {
    // Called when the item begins dragging.
    public void onItemDrag(DragNDropListView parent, View view, int position, long id);

    // Called after the item is dropped in place
    public void onItemDrop(DragNDropListView parent, View view, int startPosition, int endPosition, long id);
}

This event is useful when storing the reordered items.

Adapters

DragNDropList comes with two adapters. The first one is DragNDropCursorAdapter which is a direct replacement for SimpleCursorAdapter. The second is DragNDropSimpleAdapter which is a replacement for SimpleAdapter.

Apps that use DragNDropList

DragNDropList was originally created for our apps Tasks and Tasks Pro. Download one of them to see it in action.

If other apps use it, please let us know and we will include them here.

Contribution

If you want to contribute, there are two more projects. DragNDropListApp implements a basic demo of the DragNDropList. DragNDropListAppTest runs tests on the DragNDropListApp and contains all the tests for the DragNDropList.

If you want to contribute, please fork also those two projects and add your tests to DragNDropListAppTest.

License

DragNDropList's code uses the Apache license, see our LICENSE file.