Awesome

About the Library

inspiration

This library is strongly inspired in this concept from Hila Peleg in dribble. See it below

Android Arsenal

Working example

For more details on how to use this library please refer to the example in this repository. You can see a video of the example working here:

Adding the Library to gradle file

dependencies {
    compile 'com.diegodobelo.expandingview:expanding-view:0.9.4'
}

Using the Library

Layouts

First of all include the ExpandingList in your Activity (or Fragment) layout. This will be the list of items (ExpandItem):

<com.diegodobelo.expandingview.ExpandingList
        android:id="@+id/expanding_list_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

Now create a new layout (xml) file to represent the item (such as res/layout/expanding_item.xml). This will be the Item (header) that can be expanded to show sub items:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="94dp">
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:gravity="center_vertical|left"
        android:textSize="22sp"/>
</RelativeLayout>

Create another layout file to represent the sub items (such as /res/expanding_sub_item.xml). This will be the sub items that will be shown when the Item is expanded:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="48dp">
    <TextView
        android:id="@+id/sub_title"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerVertical="true"
        android:layout_marginLeft="8dp"
        android:textSize="18sp"
        android:gravity="center_vertical|left"/>
</RelativeLayout>

Now create a layout file (such as /res/expanding_layout.xml) to represent the whole item, including both item layout and sub item layout. We will explain each custom attribute later:

<com.diegodobelo.expandingview.ExpandingItem
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:item_layout="@layout/expanding_item"
    app:sub_item_layout="@layout/expanding_sub_item"
    app:indicator_size="42dp"
    app:indicator_margin_left="16dp"
    app:indicator_margin_right="16dp"
    app:show_indicator="true"
    app:show_animation="true"
    app:start_collapsed="true"
    app:animation_duration="250"/>

Note that we included expanding_item and expanding_sub_item layouts created before.

Java code

Now that you have all the required layouts you are able to use them in Java code. Let's start inflating the ExpandingList:

ExpandingList expandingList = (ExpandingList) findViewById(R.id.expanding_list_main);

Create a new ExpandingItem in the ExpandingList. This method receives the expanding_layout created before. Yes! We can have different layouts for different items in the same list. The items will be created based on expanding_item layout and the sub items will be created based on expanding_sub_item layout:

ExpandingItem item = expandingList.createNewItem(R.layout.expanding_layout);

/*ExpandingItem extends from View, so you can call
findViewById to get any View inside the layout*/
(TextView) item.findViewById(R.id.title)).setText("It Works!!");

Let's create the sub items. There is a method to create items in batch:

//This will create 5 items
item.createSubItems(5);

//get a sub item View
View subItemZero = item.getSubItemView(0);
((TextView) subItemZero.findViewById(R.id.sub_title)).setText("Cool");

View subItemOne = item.getSubItemView(1);
((TextView) subItemOne.findViewById(R.id.sub_title)).setText("Awesome");

...

For each item you can set the indicator color and the indicator icon:

item.setIndicatorColorRes(R.color.blue);
item.setIndicatorIconRes(R.drawable.ic_icon);

ExpandingItem layout attributes

Attribute Name	Type	Default Value	Meaning	Mandatory
item_layout	reference		The layout for the Item (header).	Yes
sub_item_layout	reference		The layout for the sub items.	Yes
separator_layout	reference		A layout to separate items.	No
indicator_size	dimension	0dp	The indicator size in dp.	No
indicator_margin_left	dimension	0dp	The margin between the indicator and its left.	No
indicator_margin_right	dimension	0dp	The margin between the indicator and its right.	No
show_indicator	boolean	true	true if you want to show the indicator. false otherwise.	No
show_animation	boolean	true	true if you want to show animations. false otherwise.	No
start_collapsed	boolean	true	true if you want the sub views to start collapsed. false otherwise.	No
animation_duration	integer	300ms	The animations duration in milliseconds.	No

ExpandingList public methods

`public void createNewItem(int layoutId)`

Method to create and add a new item.

Parameters: layoutId — The item Layout

`public void removeItem(ExpandingItem item)`

Method to remove an item.

Parameters: item — The item to be removed, of type {@link ExpandingItem}

`public void removeAllViews()`

Method to remove all items.

`ExpandingItem getItemByIndex(int index)`

Method to get an Item from the ExpandingList by its index.

Parameters: index — The index of the item.
Returns: An {@link ExpandingItem} in the list.

`public int getItemsCount()`

Return how many items exists in the list.

Returns: Items count.

ExpandingItem public methods

`public void setStateChangedListener(OnItemStateChanged listener)`

Set a listener to listen item stage changed.

Parameters: listener — The listener of type {@link OnItemStateChanged}

`public boolean isExpanded()`

Tells if the item is expanded.

Returns: true if expanded. false otherwise.

`public int getSubItemsCount()`

Returns the count of sub items.

Returns: The count of sub items.

`public void collapse()`

Collapses the sub items.

`public void toggleExpanded()`

Expand or collapse the sub items.

`public void setIndicatorColorRes(int colorRes)`

Set the indicator color by resource.

Parameters: colorRes — The color resource.

`public void setIndicatorColor(int color)`

Set the indicator color by color value.

Parameters: color — The color value.

`public void setIndicatorIconRes(int iconRes)`

Set the indicator icon by resource.

Parameters: iconRes — The icon resource.

`public void setIndicatorIcon(Drawable icon)`

Set the indicator icon.

Parameters: icon — Drawable of the indicator icon.

`@Nullable public View createSubItem()`

Creates a sub item based on sub_item_layout Layout, set as ExpandingItem layout attribute.

Returns: The inflated sub item view.

`@Nullable public View createSubItem(int position)`

Creates a sub item based on sub_item_layout Layout, set as ExpandingItem layout attribute. If position is -1, the item will be added in the end of the list.

Parameters: position — The position to add the new Item. Position should not be greater than the list size.
Returns: The inflated sub item view.

`public void createSubItems(int count)`

Creates as many sub items as requested in {@param count}.

Parameters: count — The quantity of sub items.

`public View getSubItemView(int position)`

Get a sub item at the given position.

Parameters: position — The sub item position. Should be > 0.
Returns: The sub item inflated view at the given position.

`public void removeSubItemAt(int position)`

Remove sub item at the given position.

Parameters: position — The position of the item to be removed.

`public void removeSubItemFromList(View view)`

Remove the given view representing the sub item. Should be an existing sub item.

Parameters: view — The sub item to be removed.

`public void removeSubItem(View view)`

Remove the given view representing the sub item, with animation. Should be an existing sub item.

Parameters: view — The sub item to be removed.

`public void removeAllSubItems()`

Remove all sub items.

License

 Copyright (c) 2016, Diego Bezerra <diego.bezerra@gmail.com>
 Permission to use, copy, modify, and/or distribute this software for any purpose
 with or without fee is hereby granted, provided that the above copyright notice
 and this permission notice appear in all copies.
 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
 OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.