Develop Reference

How to restrict bound service to be called by particular packages

I have written a bound service and I would like this service to be only called from particular app. I do not want other apps to be able to make calls to this service.
The options I know so far are:
Use a permission. There seems to be 3 secured permission, dangerous, signature and signatureOrSystem. Unfortunately, none of these permissions will work for me as I don't want users to accept this permission also both app does not have same signature and these are not system app.
Get app name on service bind or when making a call to service. I looked up a way to do this on stackoverflow here. This unfortunately does not works for me as it always returns the app ID in which the service resides.
Is there any other option for me or I can use the above mentioned options with some change to achieve the desired requirement.
Bound Service Code
public class SampleCommsService extends Service {
private static Messenger messanger;
#Override
public IBinder onBind(Intent intent) {
Log.e("TEST", "package intent: " + intent.getPackage());
String callingApp = MyApplication.getAppContext().getPackageManager().getNameForUid(Binder.getCallingUid());
Log.e("TEST", "onBind - package name: " + callingApp);
return getMyBinder();
}
private synchronized IBinder getMyBinder() {
if (messanger == null) {
messanger = new Messenger(new SettingsProcessor());
}
return messanger.getBinder();
}
class SettingsProcessor extends Handler {
private static final int GET_SETTINGS_REQUEST = 1;
private static final int UPDATE_SETTINGS_RESPONSE = 2;
private static final String SETTINGS = "settings";
#Override
public void handleMessage(Message msg) {
String callingApp = MyApplication.getAppContext().getPackageManager().getNameForUid(Binder.getCallingUid());
Log.e("TEST", "handle message - package name: " + callingApp);
switch (msg.what) {
case GET_SETTINGS_REQUEST:
sendSettingsValue(msg);
break;
default:
super.handleMessage(msg);
}
}
private void sendSettingsValue(Message msg) {
try {
Message resp = Message.obtain(null, UPDATE_SETTINGS_RESPONSE);
Bundle bundle = new Bundle();
bundle.putBoolean(SETTINGS, MyApplication.isSettingsEnabled());
resp.setData(bundle);
msg.replyTo.send(resp);
} catch (RemoteException e) {
// ignore
}
}
}
}
Output on calling api:
02-01 15:21:03.138 7704-7704/my.service.package E/TEST: package intent: null
02-01 15:21:03.139 7704-7704/my.service.package E/TEST: onBind - package name: my.service.package
02-01 15:21:12.429 7704-7704/my.service.package E/TEST: handle message - package name: my.service.package

OK, I was able to solve this problem based on a given answer here. The answer given in the link obviously does not works, but you can get the app ID from the Handler used for the bound service.
class SettingsProcessor extends Handler {
#Override
public void handleMessage(Message msg) {
String callingApp = MyApplication.getAppContext().getPackageManager().getNameForUid(msg.sendingUid);
Log.e("TEST", "handle message - package name: " + callingApp);
}
}
Instead of Binder.getCallingUid(), I am using msg.sendingUid and it works fine for me.

WeChat InApp payment screen shows up only for first time

I'm trying to implement WeChat InApp payments in our app. But we are struggling to make it work.
I will try to sum it up real quick.
Given user is not logged in, WeChat login screen show up every time.
Given user is logged in, when clicked on pay button for a first time, WeChat order info screen shows up, but when clicked back, and clicked on pay button again (in our app), WeChat screen doesn’t show up.
We did implemented WXPayEntryActivity but neither onCreate, onNewIntent nor onResp are called. And yes, this activity is sending broadcast but neither toast nor log shows up.
I tried call registerApp on application started, I tried it just before creating payment req.
Did anybody come across this issue?
Can WeChat help me directly?
Want to see some code?
This is my payment class
public class WXInAppPayment {
public void startPayment(AppCompatActivity activity, PaymentDataResponse data) {
IWXAPI api = getApi(activity);
if (api.isWXAppInstalled()) {
api.sendReq(getPayRequest(data));
} else {
// Showing toast
}
}
public WXReceiver getReceiver() {
// returning BR for wechat payments
return new WXReceiver();
}
public IntentFilter getIntentFilter() {
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(Constants.WE_CHAT_BR_ID);
return intentFilter;
}
private IWXAPI getApi(AppCompatActivity activity) {
final IWXAPI api = WXAPIFactory.createWXAPI(activity, null);
api.registerApp(Constants.WE_CHAT_APP_ID);
return api;
}
private PayReq getPayRequest(PaymentDataResponse data) {
PayReq request = new PayReq();
request.appId = dataFromAPI.appId;
request.partnerId = dataFromAPI.partnerId;
request.prepayId = dataFromAPI.prepayId;
request.packageValue = dataFromAPI.packageValue;
request.nonceStr = dataFromAPI.nonceStr;
request.timeStamp = dataFromAPI.timestimeStampamp;
request.sign = dataFromAPI.sign;
return request;
}
}
And this is WXPayEntryActivity. In manifest:
<activity android:name=".wxapi.WXPayEntryActivity"
android:label="#string/app_name"
android:exported="true"/>
And class:
public class WXPayEntryActivity extends Activity implements IWXAPIEventHandler {
private final String TAG = getClass().getSimpleName();
private IWXAPI api;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
api = WXAPIFactory.createWXAPI(this, Constants.WE_CHAT_APP_ID);
api.handleIntent(getIntent(), this);
}
#Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
setIntent(intent);
api.handleIntent(intent, this);
}
#Override
public void onReq(BaseReq baseReq) {
Log.e(TAG, "onReq: " + baseReq.transaction);
}
#Override
public void onResp(BaseResp baseResp) {
Log.e(TAG, "onResp: " + baseResp.errStr + " " + baseResp.errCode);
Intent intent = new Intent(Constants.WE_CHAT_BR_ID);
intent.putExtra("error_code", baseResp.errCode);
intent.putExtra("error_string", baseResp.errStr);
sendBroadcast(intent);
finish();
}
}

I went through same issue... Your code look fine.
lets cover the scenario:
This is normal ... if user is not logged in.. Wechat App will
redirect to login screen
"Only first time payment passed" happened due to wrong packageName. consider these checks:
You need to use ApplicationId not packageName
WhiteSpace
Debug buildType by default has suffix: .debug to applicatonId
Check AppSign which is MD5 of cert you sign with.. Be careful not to use the default one for debug buildType.
Try to reassign ApplicationId and AppSign it again.(that was our issue 😞) due to hidden WS not visible.
Contact Wechat team support.. they have logs to payment.

How can I use Android TextToSpeak in a MVVMCross plugin?

I have seen plenty of examples of how to use Android TextToSpeak in an Activity, and have also managed to get this to work just fine. I've also managed to get it to work using a bound service in a plugin, but it seems overcomplicated for my purposes. Here is my VoiceService class:
public class VoiceService : IVoiceService, TextToSpeech.IOnInitListener
{
public event EventHandler FinishedSpeakingEventHandler;
private TextToSpeech _tts;
public void Init()
{
// Use a speech progress listener so we get notified when the service finishes speaking the prompt
var progressListener = new SpeechProgressListener();
progressListener.FinishedSpeakingEventHandler += OnUtteranceCompleted;
//_tts = new TextToSpeech(Application.Context, this);
_tts = new TextToSpeech(Mvx.Resolve<IMvxAndroidCurrentTopActivity>().Activity, this);
_tts.SetOnUtteranceProgressListener(progressListener);
}
public void OnInit(OperationResult status)
{
// THIS EVENT NEVER FIRES!
Console.WriteLine("VoiceService TextToSpeech Initialised. Status: " + status);
if (status == OperationResult.Success)
{
}
}
public void Speak(string prompt)
{
if (!string.IsNullOrEmpty(prompt))
{
var map = new Dictionary<string, string> { { TextToSpeech.Engine.KeyParamUtteranceId, new Guid().ToString() } };
_tts.Speak(prompt, QueueMode.Flush, map);
Console.WriteLine("tts_Speak: " + prompt);
}
else
{
Console.WriteLine("tts_Speak: PROMPT IS NULL OR EMPTY!");
}
}
/// <summary>
/// When we finish speaking, call the event handler
/// </summary>
public void OnUtteranceCompleted(object sender, EventArgs e)
{
if (FinishedSpeakingEventHandler != null)
{
FinishedSpeakingEventHandler(this, new EventArgs());
}
}
public void Dispose()
{
//throw new NotImplementedException();
}
public IntPtr Handle { get; private set; }
}
Note that the OnInit method never gets called.
In my viewmodel I'd like to do this:
_voiceService.Init();
_voiceService.FinishedSpeakingEventHandler += _voiceService_FinishedSpeakingEventHandler;
... and then later ...
_voiceService.Speak(prompt);
When I do this I get these messages in the output:
10-13 08:13:59.734 I/TextToSpeech( 2298): Sucessfully bound to com.google.android.tts
(happens when I create the new TTS object)
and
10-13 08:14:43.924 W/TextToSpeech( 2298): speak failed: not bound to TTS engine
(when I call tts.Speak(prompt))
If I was using an activity I would create an intent to get this to work, but I'm unsure how to do that in a plugin.
Thanks in advance,
David

Don't implement Handle yourself, instead derive from Java.Lang.Object
public class VoiceService : Java.Lang.Object, IVoiceService, TextToSpeech.IOnInitListener
and remove your Dispose() and Handle implementation
More info here: http://developer.xamarin.com/guides/android/advanced_topics/java_integration_overview/android_callable_wrappers/
Also, I suggest you take an async approach when implementing your service, which would make calling it from view-model something like
await MvxResolve<ITextToSpeechService>().SpeakAsync(text);

Login function with ASync networking request?

I'm using 'Retrofit' for making asynchronous network requests, how might i right a function for handling logins? For instance i've currently attempted:
public UserAuthResponse Login(String username, String password) {
try {
Callback<UserAuthResponse> getAuthCallback = new Callback<UserAuthResponse>() {
#Override
public void failure(RetrofitError arg0) {
if (arg0 != null) {
if (arg0.getMessage() != null
&& arg0.getMessage().length() > 0) {
Log.e("KFF-Retrofit", arg0.getMessage());
}
}
}
#Override
public void success(UserAuthResponse listItem,
retrofit.client.Response arg1) {
Log.e("dg", listItem.getUser().getFirstname());
}
};
service.authUser(username, MD5(password), getAuthCallback);
return response;
} catch (RetrofitError e) {
e.printStackTrace();
return null;
}
}
But this is flawed: there is no way of returning the 'UserAuthResponse' from the function? How can i pass back the result?
It seems like i need a synchronous call to the web service but then i'm hit with a 'NetworkOnMainThreadException'
What is the best practice for things like this? Sorry about the poor explanation, struggling to form the right words.

Well the things is that when you're using the Callback as your means of getting the results from Retrofit you automatically giving away the possibility of having the response returned inline. There's a few ways this can be solved. I suppose it's up to you to choose which one fits best with your design.
You could decide to not use the Callback approach and use the inline result from Retrofit but then you'd need to handle the scheduling yourself otherwise you'll hit the Exception of NetworkOnMainThreadException like you mentioned.
You could also pass in a listener to your login method. This listener could then be called by the result Callback. This could be useful if you're trying to hide Retrofit behind some sort of service layer and expose a simple login interface.
interface OnLoginListener {
onLoginSuccessful(UserAuthResponse response);
onLoginFailed(Throwable t);
}
public void Login(String username, String password, final OnLoginListener listener) {
Callback<UserAuthResponse> getAuthCallback = new Callback<UserAuthResponse>() {
#Override
public void failure(RetrofitError e) {
// You can handle Retrofit exception or simply pass them down to the listener as is
listener.onLoginFailed(e);
}
#Override
public void success(UserAuthResponse listItem,
retrofit.client.Response arg1) {
// handle successful case here and pass down the data to the listener
listener.onLoginSucessful(listItem);
}
};
service.authUser(username, MD5(password), getAuthCallback);
}

use this line i Manifest
<uses-permission android:name="android.permission.INTERNET"/>
or use this before network operation (not suggestible)
if (Build.VERSION.SDK_INT>= 10) {
ThreadPolicy tp = ThreadPolicy.LAX;
StrictMode.setThreadPolicy(tp);
}

How to display message to all users my application?

I need to implement functionality to display application news/announcements for all users.
I will do it rarely so push notification is not for me.
Are there any library or sample, how to implement this fast and easy? Or better will be to implement it in next way:
When application starts - read html file on server, if file was updated after the last attempt - display content of file in popup.

All you need is to load an html, or better, a simple text file containing the notification index like:
in yourdomain.com/notificationnumber.txt
contains
"4"
Check in your applications, probably simply using SharedPreferences for the last displayed version. Then load all notification, for example:
yourdomain.com/notification3.html
yourdomain.com/notification4.html
Display them and store the index number to know which notifcations have been shown to the user. There are no special libraries needed for such a task.

If the announcements are not very frequent, then checking the html file on the server each time the application is launched is good enough.

I feel like it depends on the styling options, which your notifications require:
if no rich styling is needed, you could simply check an XML-file, Text-file or similar for some notification information (Texts, notification coded) as bjornson proposed and then just show an AlertDialog with the specific information.
If you require rich styling, you may need to load the content from a server by utilizing a WebView. So for example your app's frontpage could partly consist of a WebView that in specific cases shows the news, which you intend to present to the user. Please note, that the WebView-technique is/was used by Facebook to update certain parts of their apps without the troubles of releasing a new version in the various App Stores.

I have used an rss-feed from a wordpress blog for this, if there is a new entry, a webview is opened and the new entry is displayed. Instead of displaying the entry, one could just parse the data and display ist (using jdom or other libraries to read the html document) We use IntentService to check once every hour, but you could just do it once on strartup.
So the Service is build like this:
public class UpdateService extends IntentService
{
//INtent Services have a constructer where you have to pass a String to the super class.
public UpdateService()
{
super("UpdateService");
}
#Override
public IBinder onBind(Intent intent)
{
return null;
}
#Override
public void onCreate()
{
super.onCreate();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
super.onStartCommand(intent, flags, startId);
return Service.START_NOT_STICKY;
}
#Override
public void onDestroy()
{
super.onDestroy();
}
//This method downloads the file from a url and checks if its well formed. It has its own thread because android does not allow access to the internet in the same thread
private void checkfornews()
{
final SAXBuilder builder = new SAXBuilder();
new Thread(new Runnable()
{
public void run()
{
// command line should offer URIs or file names
try
{
Document doc = builder.build(url);
Element root = doc.getRootElement();
readnews(root);
// If there are no well-formedness errors,
// then no exception is thrown
}
// indicates a well-formedness error
catch (JDOMException e)
{
}
catch (IOException e)
{
}
}
}).start();
}
}
//checking for the lateste link, if its a new one we have a new link to show
private void readnews(Element root)
{
List<Element> children = root.getChildren();
Iterator<Element> childrenIterator = children.iterator();
while(childrenIterator.hasNext())
{
Element child = childrenIterator.next();
List<Element> grandchildren = child.getChildren();
Iterator<Element> grandchildrenIterator = grandchildren.iterator();
int counter=0;
while(grandchildrenIterator.hasNext())
{
Element grandchild = grandchildrenIterator.next();
String name = grandchild.getName();
if(name.equals("item") && counter ==0)
{
String title="";
String link="";
String category="";
List<Element> ggc = grandchild.getChildren();
Iterator<Element> ggci= ggc.iterator();
while(ggci.hasNext())
{
Element ggch = ggci.next();
if((ggch.getName()).equals("title"))
{
title=ggch.getText();
}
if(ggch.getName().equals("link"))
{
link=ggch.getText();
}
if(ggch.getName().equals("category"))
{
category=ggch.getText();
}
}
if(category.equals("SoundOfTheCity"))
{
counter++;
Logging.i(TAG, "found some news");
String latestnews = prefs.getString("SOTCNews", "");
if(!(latestnews.equals(link)))
{
Logging.i(TAG, "and its new");
Editor edit = prefs.edit();
edit.putString("SOTCNews", link);
edit.commit();
showNotification(title, link);
}
}
}
}
}
}
private void showNotification(String title, String link)
{
//do what needs to be done with the new data
}
#Override
protected void onHandleIntent(Intent intent)
{
checkfornews();
scheduleNext();
}
private void scheduleNext()
{
int checkingDelay = UPDATE_DELAY;
Calendar cal = Calendar.getInstance();
cal.add(Calendar.HOUR, checkingDelay);
Intent intent = new Intent(this, UpdateService.class);
PendingIntent pendingIntent = PendingIntent.getService(this, UPDATEALARM, intent, 0);
AlarmManager am = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), pendingIntent);
}
}
depending on the form of the html file you have to redo the readnews method and then the showNotification method.
If you don't want to have a backend like wordpress (or use a blog-like feature) you could just store the content of a static webpage instead of the url and if this content changes, use the showNotification method. This would probably do the trick and is a lot less work.