Licence check for a pro key

Question

So I would like to make a free app with full functionality loaded in. The pro functionality will be disabled until the app detects a licensed pro key. And of course I would like

Answer 1

@MainApp

<permission android:name="myapp.permission.RESPOND" protectionLevel="signature" />

<receiver android:name=".receiver.WhichHandlesValidationResponse" android:permisssion="myapp.permission.RESPOND">
    <intent-filter>
            <action android:name="myapp.action.VALIDATION_RESPONSE" />
    </intent-filter>
</receiver>

@KeyApp

<uses-permission android:name="myapp.permission.RESPOND" />

Create LvlValidationHandler.class that contains:

Intent i = new Intent("myapp.action.VALIDATION_RESPONSE");
sendBroadcast(i);

Answer 2

You can send intents between the main app and the key app. If you are using LVL in the key app then an example callback would be:

private class MyLicenseCheckerCallback implements LicenseCheckerCallback {
    public void allow() {
        Log.i("Key", "License Accepted");
        Intent i = new Intent();
        i.setAction("intent.to.call.on.success");
        i.putExtra("licenseresult", 0);
        c.sendBroadcast(i);
        mChecker.onDestroy();
    }

    public void dontAllow() {
        Log.e("Key", "License Denied");
        Intent i = new Intent();
        i.setAction("intent.to.call.on.failure");
        i.putExtra("licenseresult", 1);
        c.sendBroadcast(i);
        mChecker.onDestroy();
    }

    public void applicationError(ApplicationErrorCode errorCode) {
        Log.i("Key", "LR Error");
        Intent i = new Intent();
        i.setAction("intent.to.call.on.error");
        i.putExtra("licenseresult", 2);
        c.sendBroadcast(i);
        mChecker.onDestroy();
    }
}

You would set up broadcast receivers in both apps to initiate the license check and handle the result. e.g.

public class License extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {

    if (intent.getAction().equals("intent.called.to.initiate.request")) {
                // Initiate the license request here (possibly using a service)
        return;
    }
}

} 

You should limit access to the intents using certificate based permissions to prevent other apps being able to send spoofed "License Success" intents.

http://developer.android.com/reference/android/content/BroadcastReceiver.html#Permissions

Short version.

Define permission in manifest

< permission android:name="my.package.LicenseCheck" android:protectionLevel="signature"/> 

Use Permission in receiver declaration:

<receiver android:name="name.of.your.receiver" android:permission="my.package.LicenseCheck"> 
<intent-filter>
    <action android:name="name.of.intent"/>
</intent-filter>
</receiver>