Develop Reference

Apache OpenNLP POSModel delay when initialized in Android

I'm creating an app on Android which uses a part of speech tagger from Apache (OpenNLP). The app works okay, but for some reason there is large delay when it creates the part of speech tagger from a database file (en-pos-maxent.bin). I'm using Android Studio, and the database is in app/res/raw/en-pos-maxent.bin. Here's the code that initializes the POSModel:
public POSModel setupPOSTagger() {
InputStream modelIn = null;
POSModel model = null;
try {
modelIn = getResources().openRawResource(R.raw.en_pos_maxent);
//the huge delay is mainly on the line below
model = new POSModel(modelIn);
} catch (IOException e) {
// Model loading failed, handle the error
e.printStackTrace();
} finally {
if (modelIn != null) {
try {
modelIn.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return model;
}
Any ideas?

DexClassLoader, reload Code fails with Signal 7

I'm trying to build a plugin-System, where DexClassLoader is fetching code from other installed apks containing fragments(my plugins), and showing them in my host. This is working quite nice.
I also like to make the plugins hotswappable, this means I can change the code from a plugin, install it new and the host will notice and will load the new code. This also works, if I'm changing the code for the first time. (Although I thought it shouldn't, it seems I've got a wrong understanding of this code:
try {
requiredClass = Class.forName(fullName);
} catch(ClassNotFoundException e) {
isLoaded = false;
}
)
If i'm trying it a second time with the same plugin, the host shuts down at requiredClass = classLoader.loadClass(fullName); with something like
libc Fatal signal 7 (SIGBUS) at 0x596ed4d6 (code=2), thread 28814
(ctivityapp.host)
Does anybody has a deeper insight in the functionality of DexClassLoader and may tell me, what is happening here? I'm quite stuck at this.
Heres the full code of the method loading the foreign code:
/**
* takes the name of a package as String, and tries to load the code from the corresponding akp using DexclassLaoder.
* Checking if a package is a valid plugin must be done before calling this.
* The Plugin must contain a public class UI that extends Fragment and implements plugin as a starting point for loading
* #param packageName The full name of the package, as String
* #return the plugins object if loaded, null otherwise
*/
private Plugin attachPluginToHost(String packageName) {
try {
Class<?> requiredClass = null;
final ApplicationInfo info = context.getPackageManager().getApplicationInfo(packageName,0);
final String apkPath = info.sourceDir;
final File dexTemp = context.getDir("temp_folder", 0);
final String fullName = packageName + ".UI";
boolean isLoaded = true;
// Check if class loaded
try {
requiredClass = Class.forName(fullName);
} catch(ClassNotFoundException e) {
isLoaded = false;
}
if (!isLoaded) {
final DexClassLoader classLoader = new DexClassLoader(apkPath, dexTemp.getAbsolutePath(), null, context.getApplicationContext().getClassLoader());
requiredClass = classLoader.loadClass(fullName);
}
if (null != requiredClass) {
// Try to cast to required interface to ensure that it's can be cast
final Plugin plugin = Plugin.class.cast(requiredClass.newInstance());
installedPlugins.put(plugin.getName(), plugin);
return plugin;
}
} catch (PackageManager.NameNotFoundException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return null;
}
Many thanks in advance!

Not that it really matters (As nobody is actually viewing this), or that I even understand what's going on, but deleting the corresponding file of the plugin in dexTemp.getAbsolutePath() before reloading it solves the problem.
PS: Tumbleweed-Badge, YAY!

Ad SDKs can't seem to get the Advertising info from the device

This is what we see from Mopub and other ad networks:
java.io.IOException: Connection failure
com.google.android.gms.ads.identifier.AdvertisingIdClient.g(Unknown
Source)
com.google.android.gms.ads.identifier.AdvertisingIdClient.getAdvertisingIdInfo(Unknown
Source)
They all seem to have the same problem.
The weird thing is that we have no problem getting the advertising id from our app whatsoever with the following source. We get the right advertising id and we have no error logs.
All the SDKs are hitting the same issue (Connection failure).
Any help appreciated.
private void getAdvertisingId(AdvertisingIdHolder receiver) {
AdvertisingIdClient.Info adInfo = null;
String id = null;
boolean isLAT = false;
try {
adInfo = AdvertisingIdClient.getAdvertisingIdInfo(App.getCtx());
id = adInfo.getId();
isLAT = adInfo.isLimitAdTrackingEnabled();
} catch (IOException e) {
SLog.e("error", e);
// Unrecoverable error connecting to Google Play services (e.g.,
// the old version of the service doesn't support getting AdvertisingId).
} catch (GooglePlayServicesNotAvailableException e) {
SLog.e("error", e);
// Google Play services is not available entirely.
} catch (GooglePlayServicesRepairableException e) {
e.printStackTrace();
}
receiver.receive(id, isLAT);
}

I went through trials and errors these days on getting advertising id. Finally I got it!
The connection error can be solved if we pass in getApplicationContext() instead of the context of current activity. Below is my working code:
private void getGaid() {
new Thread(new Runnable() {
#Override
public void run() {
try {
String gaid = AdvertisingIdClient.getAdvertisingIdInfo(
getApplicationContext()).getId();
if (gaid != null) {
Log.d("DEBUG", gaid);
// gaid get!
}
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (GooglePlayServicesRepairableException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (GooglePlayServicesNotAvailableException e) {
e.printStackTrace();
}
}
}).start();
}
getGaid() can be put in onCreate(), onResume(), or onClick() of a view, as long as the thread is called by the main ui thread.
Another thing you may need is to update google play services library to latest version. As the official document here mentioned, IOException is probably caused because the old version of the service doesn't support getting AdvertisingId.
Feel free to comment if there is any other questions.

Android Reflection - Android Jars

Case 1: Look at the code below. I am able to get Class and Method objects and it works well. Method I am trying to access is android.view.View::dispatchPointerEvent.
Case 2: When I replace class/Method with com.android.server.pm.PackageManagerService::grantPermissionsLPw, I get NoMethodFoundException. Class was accessible though.
Case 3: When I replace class/Method with android.hardware.input.InputManager::injectInputEvent, I get NoMethodFoundException. Class was accessible though.
Question is: Why some of the android class/methods are accessible via reflection and some other not?
Class _class = null;
try {
_class = Class.forName("android.view.View");
Log.i("Test", "Class found");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
Method method = null;
try {
Log.i("Test", "Pre-Method found");
method = _class.getDeclaredMethod("dispatchPointerEvent",
MotionEvent.class);
Log.i("Test", "Method found");
} catch (Exception e) {
Log.i("Test","I failed."+e.getMessage()+e.toString());
//e.printStackTrace();
}

Try this
Class _class = null;
try {
_class = Class.forName("com.android.server.pm.PackageManagerService");
Log.i("Test", "Class found");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
Method method = null;
try {
Log.i("Test", "Pre-Method found");
Class _class2 = Class.forName("android.content.pm.PackageParser$Package");
method = _class.getDeclaredMethod("grantPermissionsLPw",
_class2, boolean.class);
Log.i("Test", "Method found");
} catch (Exception e) {
Log.i("Test","I failed."+e.getMessage()+e.toString());
e.printStackTrace();
}

(Sorry but I cannot post comments, so have to post response)
Did you put the right method parameters? Where you have MotionEvent.class.

android.hardware.input.InputManager::injectInputEvent requires the android.permission.INJECT_EVENTS permission which is a system permission not available to apps. If you need to do this you'll have to root the device and sign your app as a system app.

Android Facebook SDK

I am working with Android Facebook SDK and wanted to get a friends list. I have created an "AsyncTask" for doing such a thing. I am pasting my doInBackgroundMethod here.
#Override
protected String doInBackground(String... url) {
String jsonResponse;
try {
jsonResponse = Factory.getFacebook().request(Utils.LOGGEDIN_USER_FRIENDS);
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
return jsonResponse;
}
Utils Code
public static final String LOGGEDIN_USER_FRIENDS = "me/friends";
The problem I am running in to is that it is returning an empty jsonResponse for the first time the application runs. When I open my app the second time I am getting the JsonResponse. But for the first time however I am getting empty jsonResponse.
Can any one help me out in this regard.

Well it was easy... It was messed up by creating a String variable in a Factory. Later on, the same day I saw that, and called the AsyncTask built in method get which provides the result in the same thread.