android.widget.ScrollView Class - Scrolling Text View

This section provides tutorial example on how to create a scrollable screen to view large contents of text using the android.widget.ScrollView Class.

According the Android reference document, "The TextView class also takes care of its own scrolling, so does not require a ScrollView, but using the two together is possible to achieve the effect of a text view within a larger container." But I don't know how to make TextView object to become scrollable. So I places the TextView object inside a ScrollView object to make it work.

1. Enhance my application to make the screen scrollable by editing .\src\com\herongyang\AboutAndroid.java

/* AboutAndroid.java
 * Version 3.0 - Making the screen scrollable
 * Copyright (c) 2015, HerongYang.com, All Rights Reserved.
 */
package com.herongyang;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.ScrollView;
public class AboutAndroid extends Activity {
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      String msg = "";
      
      msg += "System properties\n";
      msg += "-------------\n";
      java.util.Properties props = System.getProperties();
      java.util.Enumeration e = props.propertyNames();
      while (e.hasMoreElements()) {
         String k = (String) e.nextElement();
         String v = props.getProperty(k);
         msg += k+": "+v+"\n";
      }

      TextView tv = new TextView(this);
      tv.setText(msg);
      ScrollView sv = new ScrollView(this);
      sv.addView(tv);
      setContentView(sv);
   }
}

2. Uninstall the previous version, build, install and run this new version. Some system properties are displayed:

AboutAndroid with ScrollView
AboutAndroid System Properties

Very nice. I can scroll down to see all system properties now!

After reviewing the output, I see several interesting system properties on my Android emulator:

java.home: /system
java.vm.name: Dalvik
java.vm.version: 2.1.0
java.vm.vendor: The Android Project
java.runtime.name: Android Runtime
os.name: Linux
os.version: 3.4.67-01422-gd3ffcc7-dirty

Below was some system properties I got from my Android 4.0.3 emulator created with Android SDK R17:

java.home: /system
java.vm.name: Dalvik
java.vm.version: 1.6.0
java.vm.vendor: The Android Project
java.runtime.name: Android Runtime
os.name: Linux
os.version: 2.6.29-g46b05b2
os.arch.armv71

Last update: 2015.

Table of Contents

 About This Book

 Installing JDK 1.8 on Windows System

 Installation of Android SDK R24 and Emulator

 Installing Apache Ant 1.9 on Windows System

 Developing First Android Application - HelloAndroid

 Android Application Package (APK) Files

 Android Debug Bridge (adb) Tool

 Android File Systems

 Android 4.0.3 File Systems

AboutAndroid - Application to Retrieve System Information

 java.lang.System Class - Accessing System Information

 Creating Android Project for Simple Application

 Build, Install and Run Android Application

 System.getProperties() - Retrieving System Properties

android.widget.ScrollView Class - Scrolling Text View

 System.getenv() Method - System Environment Variables

 android.os.Environment Class - Environment Folders

 android.content.Context - Application Context Information

 android.app.Activity Class and Activity Lifecycle

 View Objects and Layout Resource Files

 Using "adb logcat" Command for Debugging

 Build Process and Package File Content

 Building Your Own Web Browser

 Android Command Line Shell

 Samsung Galaxy Tab 3 Mini Tablet

 USB Debugging Applications on Samsung Tablet

 Android Tablet - LG-V905R

 USB Debugging Applications on LG-V905R Tablet

 Android Phone - LG-P925g

 USB Debugging Applications on LG-P925g Phone

 Outdated Tutorials

 References

 PDF Printing Version