Android's TextView that can expand/collapse like the Google Play's app description

by androidexample

ExpandableTextView

ExpandableTextView is an Android library that allows developers to easily create an TextView which can expand/collapse just like the Google Play's app description. Feel free to use it all you want in your Android apps provided that you cite this project.

Requirements

API Level 8 (Froyo) and above.

Setup

The library is pushed to Maven Central as an AAR,
so you just need to add the followings to your build.gradle file:


dependencies {
    compile 'com.ms-square:expandableTextView:0.1.4'
}

Usage

Using the library is really simple, just look at the source code of the [provided sample][1].
(Look at the SampleTextListAdapter.java for the use within a ListView)

The important thing to note is that the view Ids for TextView and ImageButton must be set to
"@id/expandable_text" and "@id/expand_collapse" respectively for this library to work.

Also, you can optionally set the following attributes in your layout xml file to customize the behavior
of the ExpandableTextView.

  • maxCollapsedLines (defaults to 8)
    The maximum number of text lines allowed to be shown when the TextView gets collapsed

  • animDuration (defaults to 300ms)
    Duration of the Animation for the expansion/collapse

  • animAlphaStart (defaults to 0.7f)
    Alpha value of the TextView when the animation starts
    (NOTE)
    Set this value to 1 if you want to disable the alpha animation.

  • expandDrawable
    Customize a drawable set to ImageButton to expand the TextView

  • collapseDrawable
    Customize a drawable set to ImageButton to collapse the TextView

  <!-- sample xml -->
  <com.ms.square.android.expandabletextview.ExpandableTextView
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:expandableTextView="http://schemas.android.com/apk/res-auto"
      android:id="@+id/expand_text_view"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      expandableTextView:maxCollapsedLines="4"
      expandableTextView:animDuration="200">
      <TextView
          android:id="@id/expandable_text"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:layout_marginLeft="10dp"
          android:layout_marginRight="10dp"
          android:textSize="16sp"
          android:textColor="#666666" />
      <ImageButton
          android:id="@id/expand_collapse"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:padding="16dp"
          android:layout_gravity="right|bottom"
          android:background="@android:color/transparent"/>
  </com.ms.square.android.expandabletextview.ExpandableTextView>

// sample code snippet to set the text content on the ExpandableTextView
ExpandableTextView expTv1 = (ExpandableTextView) rootView.findViewById(R.id.sample1)
                    .findViewById(R.id.expand_text_view);
                    
// IMPORTANT - call setText on the ExpandableTextView to set the text content to display
expTv1.setText(getString(R.string.dummy_text1));

GitHub