How to license an Android app?

Question

I am going to complete my Android app. Now I want to upload my application to the Android market for a paid application. To do this, I read a document from the Android website:

Android licensing

But I want to see a demo or a project that has done such licensing. I saw a demo on the Android developer site. But there is a handler, and I want to implement this code in my mass of project activity. Mymainactivity has a splash at the beginning of the application, and I set up one handler for it. So I need an example to find out how to implement licensing in our own application.

Another thing I want to know is that is it mandatory to implement Android licensing to download a paid application to the Android market?

Is it possible to install the application as paid without licensing the Android application?
If yes, and there are any demos, please give me a link to this.

Answer 1

Before you begin, include the license library in your project as described here: Licensing Your Applications | Android Developers

• Create a new activity in your project called LicenseCheck.java

• Insert the following into this action:

  import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.content.DialogInterface; import android.content.Intent; import android.net.Uri; import android.os.Bundle; import android.provider.Settings.Secure; import android.widget.Toast; import com.android.vending.licensing.AESObfuscator; import com.android.vending.licensing.LicenseChecker; import com.android.vending.licensing.LicenseCheckerCallback; import com.android.vending.licensing.ServerManagedPolicy; /** * NOTES ON USING THIS LICENSE FILE IN YOUR APPLICATION: * 1. Define the package * of you application above * 2. Be sure your public key is set properly @BASE64_PUBLIC_KEY * 3. Change your SALT using random digits * 4. Under AllowAccess, Add your previously used MainActivity * 5. Add this activity to * your manifest and set intent filters to MAIN and LAUNCHER * 6. Remove Intent Filters from previous main activity */ public class LicenseCheck extends Activity { private class MyLicenseCheckerCallback implements LicenseCheckerCallback { @Override public void allow() { if (isFinishing()) { // Don't update UI if Activity is finishing. return; } // Should allow user access. startMainActivity(); } @Override public void applicationError(ApplicationErrorCode errorCode) { if (isFinishing()) { // Don't update UI if Activity is finishing. return; } // This is a polite way of saying the developer made a mistake // while setting up or calling the license checker library. // Please examine the error code and fix the error. toast("Error: " + errorCode.name()); startMainActivity(); } @Override public void dontAllow() { if (isFinishing()) { // Don't update UI if Activity is finishing. return; } // Should not allow access. In most cases, the app should assume // the user has access unless it encounters this. If it does, // the app should inform the user of their unlicensed ways // and then either shut down the app or limit the user to a // restricted set of features. // In this example, we show a dialog that takes the user to Market. showDialog(0); } } private static final String BASE64_PUBLIC_KEY = "PLACE YOUR BASE KEY FROM GOOGLE HERE"; private static final byte[] SALT = new byte[] { INPUT 20 RANDOM INTEGERS HERE }; private LicenseChecker mChecker; // A handler on the UI thread. private LicenseCheckerCallback mLicenseCheckerCallback; private void doCheck() { mChecker.checkAccess(mLicenseCheckerCallback); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Try to use more data here. ANDROID_ID is a single point of attack. String deviceId = Secure.getString(getContentResolver(), Secure.ANDROID_ID); // Library calls this when it done. mLicenseCheckerCallback = new MyLicenseCheckerCallback(); // Construct the LicenseChecker with a policy. mChecker = new LicenseChecker(this, new ServerManagedPolicy(this, new AESObfuscator(SALT, getPackageName(), deviceId)), BASE64_PUBLIC_KEY); doCheck(); } @Override protected Dialog onCreateDialog(int id) { // We have only one dialog. return new AlertDialog.Builder(this) .setTitle("Application Not Licensed") .setCancelable(false) .setMessage( "This application is not licensed. Please purchase it from Android Market") .setPositiveButton("Buy App", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { Intent marketIntent = new Intent( Intent.ACTION_VIEW, Uri.parse("http://market.android.com/details?id=" + getPackageName())); startActivity(marketIntent); finish(); } }) .setNegativeButton("Exit", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { finish(); } }).create(); } @Override protected void onDestroy() { super.onDestroy(); mChecker.onDestroy(); } private void startMainActivity() { startActivity(new Intent(this, MainActivity.class)); //REPLACE MainActivity.class WITH YOUR APPS ORIGINAL LAUNCH ACTIVITY finish(); } public void toast(String string) { Toast.makeText(this, string, Toast.LENGTH_SHORT).show(); } } 

• Change the base key to one provided by google, put 20 random numbers in SALT, change MainActivity.class to the main activity of your application.

• Update manifest file with new action

   <!-- Old Launch Activity Here --> <activity android:label="@string/app_name" android:name=".MainActivity" /> <!-- New License Launch Activity with all intent filters from your previous main activity --> <!-- Translucent.NoTitleBar is so that this activity is never shown to the user --> <activity android:label="@string/app_name" android:name=".LicenseCheck" android:theme="@android:style/Theme.Translucent.NoTitleBar"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> 

• Add permission In manifest tag, but not in application tag

   <uses-permission android:name="com.android.vending.CHECK_LICENSE" /> 

You are all done! Before publishing, make sure you have tested it. :) :)