package com.example.expandtextviewdemo;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 = 200;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() {@Overridepublic void onClick(View v) {trim = !trim;setText();requestFocusFromTouch();}});}private void setText() {super.setText(getDisplayableText(), bufferType);}private CharSequence getDisplayableText() {return trim ? trimmedText : originalText;}@Overridepublic 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;}
}

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

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:paddingBottom="@dimen/activity_vertical_margin"android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"tools:context=".ExpandableTextActivity" ><com.example.expandtextviewdemo.ExpandableTextViewandroid:id="@+id/lorem_ipsum"android:textSize="20sp"android:layout_width="fill_parent"android:layout_height="wrap_content" /></RelativeLayout>

package com.example.expandtextviewdemo;import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;public class ExpandableTextActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_expandable_text);String yourText = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. "+ "Ut volutpat interdum interdum. Nulla laoreet lacus diam, vitae "+ "sodales sapien commodo faucibus. Vestibulum et feugiat enim. Donec "+ "semper mi et euismod tempor. Sed sodales eleifend mi id varius. Nam "+ "et ornare enim, sit amet gravida sapien. Quisque gravida et enim vel "+ "volutpat. Vivamus egestas ut felis a blandit. Vivamus fringilla "+ "dignissim mollis. Maecenas imperdiet interdum hendrerit. Aliquam"+ " dictum hendrerit ultrices. Ut vitae vestibulum dolor. Donec auctor ante"+ " eget libero molestie porta. Nam tempor fringilla ultricies. Nam sem "+ "lectus, feugiat eget ullamcorper vitae, ornare et sem. Fusce dapibus ipsum"+ " sed laoreet suscipit. ";ExpandableTextView expandableTextView = (ExpandableTextView) findViewById(R.id.lorem_ipsum);expandableTextView.setText(yourText);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.expandable_text, menu);return true;}}