Develop Reference

Android printing with Brother SDK via WiFi throws ERROR_WRONG_LABEL despite selecting correct labelNameIndex

I've been trying to print with Brother Print SDK 3.5.1 on Android 8.1.0. I keep getting ERROR_WRONG_LABEL.
This is the code I use
void printPdf() {
// Specify printer
final Printer printer = new Printer();
PrinterInfo settings = printer.getPrinterInfo();
settings.printerModel = PrinterInfo.Model.QL_810W;
settings.port = PrinterInfo.Port.NET;
settings.ipAddress = "192.168.1.73";
settings.workPath = "storage/emulated/0/Download/";
// Print Settings
settings.labelNameIndex = LabelInfo.QL700.W62RB.ordinal();
settings.printMode = PrinterInfo.PrintMode.FIT_TO_PAGE;
settings.orientation = PrinterInfo.Orientation.PORTRAIT;
settings.isAutoCut = true;
printer.setPrinterInfo(settings);
// Connect, then print
new Thread(new Runnable() {
#Override
public void run() {
if (printer.startCommunication()) {
PrinterStatus result = printer.printPdfFile("/storage/emulated/0/Download/hello world red.pdf", 1);
if (result.errorCode != PrinterInfo.ErrorCode.ERROR_NONE) {
Log.d("TAG", "ERROR - " + result.errorCode);
}
printer.endCommunication();
}
}
}).start();
}
My printer model is QL-810W and I use the black and red W62 roll.
I've tried the Sample Application, where setting W62RB in labelNameIndex prints fine.
Changing the roll for different one with different width didn't help.
I've also tried iterating over numbers 0 to 50 and using them as labelNameIndex.
Based on this thread, I thought that the issue may be in specifying the workPath attribute. Setting workPath to getContext().getCacheDir().getPath() results in ERROR_OUT_OF_MEMORY instead of ERROR_WRONG_LABEL. Not specifying workPath and adding <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> to AndroidManifest.xml results in ERROR_WRONG_LABEL
EDIT
I've modified the Brother Sample app and uploaded it to GitHub. The app now launches Activity_PrintPdf.java by default where I inserted my printing code with hardcoded values at the beginning of onCreate method - this works fine and prints the PDF file as expected.
Then I created a new Empty Activity project in Android Studio, copy pasted the library, added the imports to build.gradle and copy pasted the permissions into AndroidManifest.xml. Then I copy pasted the printing code at the beginning of onCreate method in MainActivity.java. Running the app results in ERROR_WRONG_LABEL.
This is the modified working example app and this is the one that results in the error. I want to use the code as native module that I call from my React Native app, so it's important that I manage to set up the printing code from scratch rather than modifying the existing example app.
EDIT 2
I've inspected the library with a debugger: when executing printer.setPrinterInfo(mPrinterInfo) the library internally calls private boolean createWorkPath(String dirPath) of Printer object. On return from this method, the debugger shows Source code doesn't match the bytecode and seems to forget the created directory. This also internally sets mResult.errorCode = ErrorCode.ERROR_WORKPATH_NOT_SET. However, instead of rising any error here the code just silently proceeds, which later results in ERROR_WRONG_LABEL when trying to print. Running the same code snipper in the modified Sample app works fine.
I'd be grateful if you could help or suggest what to try next.
Thank you!

I've now fixed the issue, which was that the Brother library silently failed to create a temporarily folder and instead of reporting an error, it continued and failed later to read the label information. Based on this thread, it is now required to specify runtime file read and write permissions as opposed to the compile-time ones in AndroidManifest.xml.
Adding
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
at the beginning of onCreate before the printing code fixed the issue.

Google play game Leaderboard can not submitScore

I am trying to submit a score at a Google Game Play Leaderboard using the following code line:
if(mGoogleApiClient.isConnected()) {
Games.Leaderboards.submitScoreImmediate(mGoogleApiClient, "xxxxxxxxxxxxxxxxx", myScore).setResultCallback(new ResultCallback<Leaderboards.SubmitScoreResult>() {
#Override
public void onResult(Leaderboards.SubmitScoreResult arg0) {
Log.e(TAG, "getStatusCode= "+arg0.getStatus().getStatusCode());
Log.e(TAG, "score submitted: "+arg0.getScoreData().toString());
}
});
}
The score is not uploaded and I get the following error ScoreSubmissionData:
ScoreSubmissionData{PlayerId=xxxxxxxxxxxxxxxx, StatusCode=2, TimesSpan=DAILY, Result=null, TimesSpan=WEEKLY, Result=null, TimesSpan=ALL_TIME, Result=null}
StatusCode=2 means STATUS_CLIENT_RECONNECT_REQUIRED
I call the above line inside onConnected() method so it is sure that I am connected...

Try reconnecting or apply a Loop-switch sequence to handle error like this. You might want to check this example showing how to use STATUS_CLIENT_RECONNECT_REQUIRED of the com.google.android.gms.games.GamesClient class.
Base on the document:
STATUS_CLIENT_RECONNECT_REQUIRED
The AppStateClient is in an inconsistent state and must reconnect to the service to resolve the issue.
Also here is the list of AppStateClient that you may encounter.
Hope this helps.

I have found the solution.
The application i make was first build to an other Laptop.
Now i have bought a new Laptop, i installed Android Studio and tried to change some code lines. But when i submitted a Score my Google play account (API Manager) could not recognize my new Laptop because it had a different SHA1 key.
So i added my new SHA1 key at the credentials of the API Manager and everything was ok !!

Parse deleteEventually() method doesn't work (Android code)

I'have downloaded the code of the Parse project "OfflineTodos" (see https://github.com/ParsePlatform/OfflineTodos) for Android. It's a very simple sample app, but I'm having problems with it.
I've tried so many combinations to make this work, but I couldn't!
This is part of the original code from class "NewTodoActivity":
deleteButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// The todo will be deleted eventually but will
// immediately be excluded from query results.
todo.deleteEventually();
setResult(Activity.RESULT_OK);
finish();
}
});
VERY simple, but it doesn't work! It just delete the local Todo Object, not the server one. I've wait a lot of time with the app running, but nothing happens.
The deleteInBackground() works fine, but I need to use the deleteEventually(), because my app will run in locals with bad internet signals.
I didn't make any changes at the original code.
I want this method (deleteEventually()) to delete immediatelly when the cellphone get network, is it possible? If not, what should I do?
Thanks.

Newer versions of android (above version 5) somehow don't seem to accept deleteEventually(). For now, I would suggest a just using deleteInBackground() for the newer versions
if (Integer.valueOf(android.os.Build.VERSION.SDK) >= 21) {
object.deleteInBackground();
}else{
object.deleteEventually();
}

Lucky patcher, how can I protect from it? [duplicate]

This question already has answers here:
Way to protect from Lucky Patcher / play licensing [closed]
(8 answers)
Closed 5 years ago.
I know this topic has been opened multiple times and I learnt a lot but I stumbled across a problem I really need advice on.
I'm using LVL with Obfuscation. I changed the default LVL ALOT so that anti-LVL does not break it. However, Lucky Patcher with one click breaks it! I tried to see the new broken APK. Yes it simply called my "allow method".
My question is if someone can recommend a way to prevent Lucky Patcher from breaking it? I know I can't make it bullet-proof, but I want it at least to be not so easy for one-click software.

Code to check your certificate:
public void checkSignature(final Context context) {
try {
Signature[] signatures = context.getPackageManager().getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES).signatures;
if (signatures[0].toCharsString() != <YOUR CERTIFICATE STRING GOES HERE>) {
// Kill the process without warning. If someone changed the certificate
// is better not to give a hint about why the app stopped working
android.os.Process.killProcess(android.os.Process.myPid());
}
}
catch (NameNotFoundException ex) {
// Must never fail, so if it does, means someone played with the apk, so kill the process
android.os.Process.killProcess(android.os.Process.myPid());
}
}
Next how to find which one is your certificate. You must produce an APK, in release mode, as the debug certificate is different from the release one. Output your certificate into your Logcat:
signatures[0].toCharsString();
Remember that when you are back to debug mode, the certificate is different again. To avoid debug issues use next line to skip the verification:
if ((context.getApplicationContext().getApplicationInfo().flags &= ApplicationInfo.FLAG_DEBUGGABLE) != 0)
return;
Next the lucky patcher checker.
I decompiled all versions of Lucky Patcher, and I've found that its creator used 2 package names between all realeases. So you only need to keep track of new versions and keep adding future package names.
private boolean checkLuckyPatcher() {
if (packageExists("com.dimonvideo.luckypatcher"))
return true;
if (packageExists("com.chelpus.lackypatch"))
return true;
if (packageExists("com.android.vending.billing.InAppBillingService.LACK"))
return true;
return false;
}
private boolean packageExists(final String packageName) {
try {
ApplicationInfo info = this.getPackageManager().getApplicationInfo(packageName, 0);
if (info == null) {
// No need really to test for null, if the package does not
// exist it will really rise an exception. but in case Google
// changes the API in the future lets be safe and test it
return false;
}
return true;
}
catch (Exception ex) {
// If we get here only means the Package does not exist
}
return false;
}

As of current version (6.4.6), Lucky Patcher generates very short token. For example, real purchase token:
felihnbdiljiajicjhdpcgbb.AO-J1OyQgD6gEBTUHhduDpATg3hLkTYSWyVZUvFwe4KzT3r-O7o5kdt_PbG7sSUuoC1l6dtqsYZW0ZuoEkVUOq5TMi8LO1MvDwdx5Kr7vIHCVBDcjCl3CKP4UigtKmXotCUd6znJ0KfW
And that is Lucky Token:
kvfmqjhewuojbsfiwqngqqmc
Pretty straight forward solution is to check string length of token
#Override public void onIabPurchaseFinished(IabResult result, Purchase info) {
if (info.getToken().length < 25) {
Log.wtf("PIRATE", "PIRATE DETECTED");
return;
}
}

Implement a function that gets called under certain actions, and which checks whether the LuckyPatcher package is installed in the device.
If found, then exit your app. Don’t allow to use it regardless if is paid or not, better bad reviews than thousands of illegal copies. Alternatively you could show a message stating that LuckyPatcher has been found and the app can't run.
If your app gets patched by LuckyPatcher, meaning that it has hacked your LVL implementation, then at least your app will not execute due to the LuckyPatcher package detection.

A way, is to check if lucky patcher is installed and if so, then show a message to the user, and kill your process afterwards. If a user has it, means he is trying to crack your software or other developer's one. So better not to allow to use your app in a phone that has it installed. Fight piracy.

Whenever Lucky Patcher creates a modded APK file, it always ends up with a different package name, as you can't run two apps under the same package name.
Here's a simple solution that checks if your code is running under the wrong package name:
PackageManager pm = getPackageManager();
try {
PackageInfo packageInfo = pm.getPackageInfo("YOUR_PACKAGE_NAME",PackageManager.GET_ACTIVITIES);
} catch (PackageManager.NameNotFoundException e){
finish();
//If you get here, your code is running under a different package name... Kill the process!
}
I just call finish(); on my app and I can't break it, but it might be best to use android.os.Process.killProcess(android.os.Process.myPid()); as #PerracoLabs suggested.

Unauthorized Caller Error

I am stuck writing some code that uses reflection that calls IConnectivityManager.startLegacyVpn
The error I get is java.lang.SecurityException: Unauthorized Caller
Looking through the android source I see this is the code hanging me up:
if (Binder.getCallingUid() != Process.SYSTEM_UID) { raise the above exception }
My question is if I root my AVD and install my app in system/app will this be sufficient to get around this error?
If so, any tips on how to do this (every time I try to move my apk to the system/app folder it says the app is not installed when I click on the app icon.
Thanks!

I have the same problem, following android 4.01 open source, i see somethings like this:
public synchronized LegacyVpnInfo getLegacyVpnInfo() {
// Only system user can call this method.
if (Binder.getCallingUid() != Process.SYSTEM_UID) {
throw new SecurityException("Unauthorized Caller");
}
return (mLegacyVpnRunner == null) ? null : mLegacyVpnRunner.getInfo();
}
Or,
// Only system user can revoke a package.
if (Binder.getCallingUid() != Process.SYSTEM_UID) {
throw new SecurityException("Unauthorized Caller");
}
Or,
public void protect(ParcelFileDescriptor socket, String interfaze) throws Exception {
PackageManager pm = mContext.getPackageManager();
ApplicationInfo app = pm.getApplicationInfo(mPackage, 0);
if (Binder.getCallingUid() != app.uid) {
throw new SecurityException("Unauthorized Caller");
}
jniProtect(socket.getFd(), interfaze);
}
However, these block of code above is belongs to com.android.server.connectivity.Vpn
(class Vpn), which is not defined in interface IConnectivityManager.
I also find in startLegacyVpnInfo() function but i can't see anything involve exception
"Unauthorized Caller", so i wonder why startLegacyVpnInfo() function throws this exception?
Any solutions for this?

I am trying to make the same calls. So far I can confirm that rooting the device and copying the apk to /system/app does not work, it does not start under the system uid.
Also, this does not work:
Field uidField = Process.class.getDeclaredField("SYSTEM_UID");
uidField.setAccessible(true);
uidField.set(null, Process.myUid());
Those calls succeed, but they don't seem to affect the SYSTEM_UID field, the field is probably optimized out at compile time.

If you include android: sharedUserId="android.uid.system" into your manifest tag (not just the manifest), this should then run the application as system. This should now let you run the code.
As for pushing to /system/app, you need to run adb root followed by adb remount. This will now let you push to /system/app.