Expandable Textview

ExpandableTextView is a 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.

1.attrs.xml

Add attribute to attrs.xml in values folder.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="ExpandableTextView">
        <attr name="trimLength" format="integer"/>
    </declare-styleable>
</resources>

2.ExpandableTextView.java

package com.myapplication;

import android.content.Context;
import android.content.res.TypedArray;
import android.text.SpannableStringBuilder;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;

public class ExpandableTextView extends TextView {
    private static final int DEFAULT_TRIM_LENGTH = 50;
    private static final String ELLIPSIS = " ...";
    private CharSequence originalText;
    private CharSequence trimmedText;
    private BufferType bufferType;
    private boolean trim = true;
    private int trimLength;

    public ExpandableTextView(Context context) {
        this(context, null);
    }

    public ExpandableTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ExpandableTextView);
        this.trimLength = typedArray.getInt(R.styleable.ExpandableTextView_trimLength, DEFAULT_TRIM_LENGTH);
        typedArray.recycle();

        setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                trim = !trim;
                setText();
                requestFocusFromTouch();
            }
        });
    }

    private void setText() {
        super.setText(getDisplayableText(), bufferType);
    }

    private CharSequence getDisplayableText() {
        return trim ? trimmedText : originalText;
    }

    @Override
    public void setText(CharSequence text, BufferType type) {
        originalText = text;
        trimmedText = getTrimmedText(text);
        bufferType = type;
        setText();
    }

    private CharSequence getTrimmedText(CharSequence text) {
        if (originalText != null && originalText.length() > trimLength) {
            return new SpannableStringBuilder(originalText, 0, trimLength + 1).append(ELLIPSIS);
        } else {
            return originalText;
        }
    }

    public CharSequence getOriginalText() {
        return originalText;
    }

    public void setTrimLength(int trimLength) {
        this.trimLength = trimLength;
        trimmedText = getTrimmedText(originalText);
        setText();
    }

    public int getTrimLength() {
        return trimLength;
    }
}

3.activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_horizontal">

    <com.myapplication.ExpandableTextView
        android:id="@+id/text"
        android:layout_width="200dp"
        android:layout_height="wrap_content" />
</LinearLayout>

4.MainActivity.java

public class MainActivity extends Activity {
    Spannable.Factory spannableFactory;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        spannableFactory = Spannable.Factory
                .getInstance();

        String text = "ExpandableTextView is a 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.";
        final ExpandableTextView textView = (ExpandableTextView) findViewById(R.id.text);
        textView.setText(text);
    }
}