Develop Reference

Firebase - Android - fetchProvidersForEmail - Why are all the calls asynchronous?

I'm new to Firebase and I'm having a lot of problems with the fact that all the tasks are called asynchronously.
For example, I am trying to use fetchProvidersForEmail to know if I should direct the user to sign up or log in. However, by the time the task finishes, it's too late.
I am not sure if it's clear but here is my current code (which works) and below is the method I would want to create. How can I get that done?
public static void printProviders(String email) {
FirebaseAuth auth = FirebaseAuth.getInstance();
auth.fetchProvidersForEmail(email).addOnCompleteListener(new OnCompleteListener<ProviderQueryResult>() {
#Override
public void onComplete(#NonNull Task<ProviderQueryResult> task) {
Log.d(TAG, "We have " + task.getResult().getProviders().size() + " results.");
for (int i = 0; i < task.getResult().getProviders().size(); i++) {
Log.d(TAG, "Provider " + (i+1) + ": " + task.getResult().getProviders().get(i));
}
}
}
);
}
Here is the pseudo-code of the method I would want to create (of course, this doesn't work)...
public static boolean emailIsRegistered(String email) {
FirebaseAuth auth = FirebaseAuth.getInstance();
auth.fetchProvidersForEmail(email).addOnCompleteListener(new OnCompleteListener<ProviderQueryResult>() {
#Override
public void onComplete(#NonNull Task<ProviderQueryResult> task) {
if (task.getResult().getProviders().size() > 0) {
return true;
}
return false;
}
});
}
However, this does not work because the return statement is void for onComplete() and because the task is executed asynchronously...
I am new to this. I tried to search through StackOverflow but couldn't find anything that helped me. Hopefully someone can help.
Thank you!

When you call fetchProvidersForEmail that information is not available in the APK of your app. The Firebase client has to call out to the servers to get this information.
Given the nature of the internet, this means that it will take an undetermined amount of time before the result comes back from those servers.
The client has a few options on what to do in the meantime:
wait until the data is available
continue executing and calling you back when the data is available
Waiting for the data would mean that your code stays simple. But it also means that your app is blocked while the data is being looked up. So: no spinner animation would run, the user can't do anything else (which may be fine for your app, but not for others), etc. This is considered a bad user experience. So bad in fact, that Android will show an Application Not Responding dialog if your app is in this state for 5 seconds.
So instead, the Firebase SDKs choose the other option: they let your code continue, while they're retrieveing the data from the servers. Then when the data is retrieved, they call back into a code block you provided. Most modern web APIs are built this way, so the sooner you come to grips with it, the sooner you can efficiently use those APIs.
The easiest way I found to grasps asynchronous programming is by reframing your problems. Right now you're trying to "first determine if the email is already used, then sign the user up or in".
if (emailIsRegistered(email)) {
signInUser(email);
}
else {
signUpUser(email);
}
This approach leads to a emailIsRegistered method that returns a boolean, something that is impossible with asynchronous methods.
Now let's reframe the problem to "determine if the email is already used. When we know this, sign the user up or in".
This leads to a different piece of code:
public static boolean emailIsRegistered(String email) {
FirebaseAuth auth = FirebaseAuth.getInstance();
auth.fetchProvidersForEmail(email).addOnCompleteListener(new OnCompleteListener<ProviderQueryResult>() {
#Override
public void onComplete(#NonNull Task<ProviderQueryResult> task) {
if (task.getResult().getProviders().size() > 0) {
signUserIn(email);
}
signUserUp(email);
}
});
We've moved the calls to sign the user up or in into the emailIsRegistered method and invoke then when the result becomes available.
Now this of course hard-coded the follow up action into the emailIsRegistered method, which makes it harder to re-use. That's why you quite often see a callback being passed into these functions. A great example of that is the OnCompleteListener that you're already using. Once the Firebase client gets the result from the servers, it calls the onComplete method that you passed in.
Learning to deal with asynchronous calls is both hard and important. I'm not sure if this is my best explanation of the concepts ever. So I'll include some previous explanations (from both me and others):
Setting Singleton property value in Firebase Listener
Firebase Android: How to read from different references sequentially
Is it possible to synchronously load data from Firebase?
Knowing when Firebase has completed API call?
Gathering data from Firebase asynchronously: when is the data-set complete?
What is callback in Android?

Android background threading

I'm making image processor app. I need to scan the phone for pictures and list them with their number of pixels. So that's gonna be a a large impact on performance and as I understood, I need to make it work on background thread.
So my question is, what is the best approach for this? I understand that IntentService may be the best solution, but I'm not sure how I will implement progress bar with it, and I need to return Picture objects and later update the UI on shuffle button. I'm doing update with Glide library so that's gonna go smooth.
Reading about Asynctasks, I stumbled about comments how it's bad and leads to leaks in memory and should avoid using it. rXJava is too complicated at the moment.
This is my code:
Main activity:
#OnClick(R.id.shuffle)
public void shuffleList() {
Collections.shuffle(listOfImageFiles);
recyclerViewAdapter = new PictureRecycleViewAdapter(listOfImageFiles, this);
recyclerView.swapAdapter(recyclerViewAdapter, false);
recyclerViewAdapter.notifyDataSetChanged();
}
#OnClick(R.id.scan)
public void processImages() {
//progress bar
listOfPictures = new ArrayList<>();
//Gets data from default camera roll directory. Note that some of the phone companies have different file paths. So instead of hardcoding string paths, I used this instead.
String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getPath();
File filePath = new File(path);
listOfImageFiles = scanPhotos(filePath);
// async?
for (File file : listOfImageFiles
) {
Bitmap bitmap = BitmapFactory.decodeFile(file.getPath());
//int is sufficient for most today's pixels. long would be overkill - 4 vs 8 bytes
int pixels = bitmap.getHeight() * bitmap.getWidth();
listOfPictures.add(new Picture(file.getPath(), pixels));
}
}
public List<File> scanPhotos(File directory) {
List<File> listOfPictures = new ArrayList<>();
try {
File[] files = directory.listFiles();
for (File file : files
) {
if (file.isDirectory() && !file.isHidden()) {
listOfPictures.addAll(scanPhotos(file));
} else {
if (file.getName().endsWith(".jpg") || file.getName().endsWith(".jpeg") || file.getName().endsWith(".png")) {
listOfPictures.add(file);
}
}
}
} catch (Exception e) {
Log.e(e.getMessage(), e.getMessage());
}
return listOfPictures;
}

IntentService
IntentService is definitely a valid approach. You can use Broadcasts to return your result to another component of the app, be it Activity or another Service, for example:
Start the IntentService - if you need some parameters, place them in the Extras of the service intent.
Your IntentService runs on the background thread until the computation is finished.
Upon finishing, send a broadcast with computation result placed in intent extras.
In your activity, register a BroadcastReceiver that will listen for your computation result broadcast.
Upon getting the broadcast in your Activity, retrieve the computation result from intent extras.
You might also implement broadcasts received by your Service for things like cancellation of the computation or updating the parameters.
One of the advantages of IntentService is that you can easily integrate it with the JobScheduler API to defer execution until certain system conditions are met.
Alternatives
You can use a bus library, such as https://github.com/greenrobot/EventBus to communicate between Activity and Service - the only problem is, EventBus won't work with remote services (running in a separate process).
Like you've mentioned, using RxJava with IO and computation schedulers is also a good idea.
AsyncTask is fine as long as you not tie it with a hard reference to an activity - don't implement it as an inner class of Activity and if you want to communicate the result back, do it through a WeakReference<T>

AsyncTask is fine, you just need to be careful with its implementation.
However, for longer running tasks there are better options. IntentService is a good option.
When it comes to a responsive UI when using an IntentService you could add two things.
Notifications
Create an ongoing notification that indicates that your App is working on something. This lets users know that their CPU cycles are being eaten by something in the background and they are less likely(?) to be confused and cranky about their device running slower.
Additionally, it gives your App more of an allowance for staying alive when Android is looking for background Apps to kill to release memory.
EventBus
You can make UI reporting extremely simple by using an EventBus library. I am personally a fan of greenbot/EventBus, but there are others.
Example
In your Activity:
#Subscribe(threadMode = ThreadMode.MAIN)
public void onProgressEvent(ProgressEvent event) {
mProgressBar.setProgress(event.value);
}
In your IntentService:
EventBus.getDefault().post(new ProgressEvent(5000));

How many mayLaunchUrl we can run at a time?

I am trying to utilize ChromeCustomTabs into our project. I ran into several issue when I used mayLaunchUrl. I checked the code Google has on the github. I simply set up an button to test the mayLaunchURL (prerender feature), when I looked up the traffic using chrome dev tool. I did the the traffic and tab got trigger and the url got loaded ( it is simply a GET call with params). However, when I click it multiple times, (after 8-10times, with different params everytime), it STOP working. I stop seeing the requests sent out. (Not seen on chrome dev tool, nor the Proxy I set up).
I wonder if there is a limit times ( restriction) for mayLaunchURL feature, in other words, how many pages we can pre-render in this case? Is there a way to manually cancel the pre-render page and free the resource?
is there a restriction in terms of times to bindCustomTabsService? The way I did to call mayLaunchURL is to have an activity and kill the activity once I finish the tab. Can I bind the service each time even I “kill (finish)” the activtiy every time?
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
customTabActivityHelper = new CustomTabActivityHelper();
customTabActivityHelper.setConnectionCallback(this);
}
#Override
protected void onStart() {
super.onStart();
customTabActivityHelper.bindCustomTabsService(this);
}
#Override
public void onCustomTabsConnected() {
Boolean mayLaunchUrlAccepted = customTabActivityHelper.mayLaunchUrl(Uri.parse(“the URL?f=“+params), null, null);
// the mayLaunchUrlAccepted always return true in my case. Even when there is no request sent.
}

Yes, mayLaunchURL() are very expensive in terms of battery/RAM/network, so it is throttled on app UID level. But limits get dropped after some time.
Best strategy is to use mayLaunchURL() if the confidence that the user will navigate to the URL is very high.
There is the "low confidence" mayLaunchURL() which is not throttled, but performs a more limited set of actions (currently preconnect, not specified which, may change). The low confidence mayLaunchURL is triggered by providing null as the uri and a list of URLs in otherLikelyBundles.

Google Drive Android API: Deleted folder still exists in query

Running the code below, I create a folder with Google Drive Android API on a tablet. After a few seconds, delete that folder from a remote location on a PC. When I re-run the code, the API still thinks 'MyFolder' exists, even though it was deleted and not visible in the Google Drive app on the tablet. The folder persistance finally disappears after a while and the code works as expected. Is this expected behavior for Cloud drives?
Query query = new Query.Builder()
.addFilter(Filters.and(Filters.eq(
SearchableField.TITLE, "MyFolder"),
Filters.eq(SearchableField.TRASHED, false)))
.build();
Drive.DriveApi.query(getGoogleApiClient(), query)
.setResultCallback(new ResultCallback<DriveApi.MetadataBufferResult>() {
#Override
public void onResult(DriveApi.MetadataBufferResult result) {
if (!result.getStatus().isSuccess()) {
showMessage("Cannot create folder in the root.");
} else {
boolean isFound = false;
for(Metadata m : result.getMetadataBuffer()) {
if(!isFound) {
if (m.getTitle().equals("MyFolder")) {
showMessage("Folder exists");
isFound = true;
}
}
}
if(!isFound) {
showMessage("Folder not found; creating it.");
MetadataChangeSet changeSet = new MetadataChangeSet.Builder()
.setTitle("MyFolder")
.build();
Drive.DriveApi.getRootFolder(getGoogleApiClient())
.createFolder(getGoogleApiClient(), changeSet)
.setResultCallback(new ResultCallback<DriveFolder.DriveFolderResult>() {
#Override
public void onResult(DriveFolder.DriveFolderResult result) {
if (!result.getStatus().isSuccess()) {
showMessage("Error while trying to create the folder");
} else {
mThwingAlbertFolderId = result.getDriveFolder().getDriveId();
showMessage("Created a folder: " + mThwingAlbertFolderId);
}
}
});
}
}
}
});

What you are seeing, is a 'normal' behavior of the GDAA, that can be explained if you look closer at the 'Lifecycle of a Drive file' diagram (warning: I've never seen the source code, just assuming from what I observed).
See, the GDAA, unlike the REST Api, creates a layer that does its best to create caching and network traffic optimization. So, when you manipulate the file/folder from the 'outside' (like the web app), the GDAA layer has no knowledge of the fact until it initiates synchronization, controlled by it's own logic. I myself originally assumed that GooDrive has this under control by dispatching some kind of notification back to the GDAA, but it apparently is not the case. Also, some Googlers mentioned 'requestSync()' as a cure, but I never succeeded to make it work.
What you think you're doing, is polling the GooDrive. But effectively, you're polling the GDAA (local GooPlaySvcs) whose DriveId is still valid (not updated), unlike the real GooDrive object that is already gone.
This is one thing that is not clearly stated in the docs. GDAA is not the best Api for EVERY application. It's caching mechanism is great for transparently managing online/offline states, network traffic optimization. battery life, ... But in your situation, you may be better off by using the REST Api, since the response you get reflects the current GooDrive state.
I myself faced a similar situation and had to switch from the GDAA back to the REST (and replaced polling with a private GCM based notification system). Needless to say, by using the REST Api, your app gets more complex, usually requiring sync adapter / service to do the data synchronization, managing network states, ... all the stuff GDAA gives you for free).
In case you want to play with the 2 apis side-by side, there are two identical CRUD implementation you can use (GDAA, REST) on Github.
Good Luck

Google drive api does not sync immediately, That is why the deleted folders are still showing, so you have to force google drive to sync using requestSync()
Drive.DriveApi.requestSync(mGoogleApiClient).await();
I fount an example snippet here:
http://wiki.workassis.com/android-google-drive-api-deleted-folder-still-exists-in-query/

As Sean mentioned, the Drive Android API caches metadata locally to reduce bandwidth and battery usage.
When you perform an action on the device, e.g. creating a folder, we attempt to apply that action on the server as soon as possible. Though there can be delays due to action dependencies and content transfers, you will generally see the results reflected on the server very quickly.
When an action is performed on the server, e.g. by deleting a folder via the web client, this action is reflected on the device the next time the Drive Android API syncs. In order to conserve battery and bandwidth, sync frequency depends on how the API is being used as this is a priority for users.
If you need to guarantee that a sync has occurred, you can explicitly request a sync using DriveApi.requestSync() and wait on the result. This is currently rate limited to 1 per minute, which is frequently hit during testing, but should have a much smaller impact on real world usage.
Please let us know on our issue tracker if this sync behavior is causing issues for your use case so we can investigate solutions.

Google drive uses its own lifecycle for Drive api and manage all things in cache that's why if you delete some file or folder and try to access using google drive apis it is still available because it is stored in cache so you need to explicitly call requestSync() method for that then after that cache will be updated and gives you that folder or file not found.
below is code for that:
Drive.DriveApi.requestSync(mGoogleApiClient).setResultCallback(new ResultCallback<Status>() {
#Override
public void onResult(#NonNull Status status) {
Log.e("sync_status", status.toString());
if (status.getStatus().isSuccess()) {
setRootFolderDriveId();
}
}
});
and don't call Drive.DriveApi.requestSync(mGoogleApiClient).await() because your main thread will block so it will crash. use above one and after get successful callback you can do your operation on google drive because it's updated.

You can do it in main thread:
Drive.DriveApi.requestSync(mGoogleApiClient).setResultCallback(new ResultCallback<com.google.android.gms.common.api.Status>() {
#Override
public void onResult(com.google.android.gms.common.api.Status status) {
if (!status.getStatus().isSuccess()) {
Log.e("SYNCING", "ERROR" + status.getStatusMessage());
} else {
Log.e("SYNCING", "SUCCESS");
// execute your code to interact with Google Drive
}
}
});

I was having the same issue and using "Drive.DriveApi.requestSync" did the trick.
Also I suggest taking a look at https://github.com/francescocervone/RxDrive because you can concatenate the sync to other drive operations using rxandroid.
For example, this becomes a delete-and-sync operation:
Observable<Boolean> deleteFile = rxDrive.delete(file);
Observable<Void> syncDrive = rxDrive.sync();
Observable.concat(deleteFile, syncDrive);

The reason why you get listed deleted files from your query is that Google Drive has a "Trash" folder that is "searchable". You need to empty your trash first.

How to notify users about an Android app update?

I've built an Android app which is now on Play Market. From time to time, I make updates to it, and I'd like to let users know that a new version is available.
How can I send an update notification to the users of the app?

You do not need to do anything specific for this. Since you mentioned that you are using Google Play, the update notification is taken care of by Google Play.
You just need to update the APK with a higher versionCode and Google Play should do the rest.

Update 2020: now you can use in-app updates mechanism
Docs: https://developer.android.com/guide/playcore/in-app-updates

You can do this in a lot of ways, depending on when you want the user to be able to see that there is an update available.
If you want the user to know about the update when the app is started, just create a utility method (inside the onCreate method of your main/first Activity) that checks if a newer version is available in Google Play. If it does, display an alert dialog with a relevant message and an Intent which opens your app in Google Play when the user clicks on the positive button of the alert dialog.
If you are updating the app regularly, the user will keep getting this alert dialog every time the app is started and hence, may get irritated. Thus, this is not the best approach.
If you want the user to get a notification on the phone (and not when the user starts the app), you can use the AlarmManager class to schedule a background service which checks for an update at regular intervals. If the service finds that an upgrade is actually available, publish a notification with an intent that opens your app in Google Play.
Of course, another approach is to leave it to the OS itself. If the user has not set the "Automatically update" preference for your app, the user will get a notification regularly about an update available for your, as well as any other apps.
But not all users enable background data on their devices, so this is not completely reliable.
In the end, you must respect the users preferences. If the user does not want to automatically update the app, or does not want to see a nagging dialog box whenever he/she starts your app, don't alert the user about the update.
In my opinion, you should create a PreferenceActivity that has a preference like "Check for updates regularly", which can be set from within your app. If it is set, do the needful in your own service. May be even give the user an option to select the period after which the service will check for an update.
I hope this helps!

It is up to each phone owner if she wants to be notified on new versions by google play, and it's up to each phone's manufacturer if this is to be enabled by default.
If you however are in a situation where you "require" the user to update to the new version to be compatible with some form of protocol or you have a similar similar use case where you have a server component somewhere, you might want to notify the user of a potential version conflict in the UI based on information about what is the latest version.
This information can be grabbed directrly from google play, however as #Yahel pointed out in this question google play is a closed system with no official API, and you might need to rely on unpredictable undocumented API. There is an unofficial API library here.
This leaves only one option, which is to keep this information on your own server. If you allready have a serverside this might be trivial. Simply put the latest version in an XML file and retreive that at regular intervals from your code. If the version code is outdated, trigger the notification in your UI. Here is an example implementation for doing that.
I hope this was helpful :-)

I know this is an old question but still if people are coming here to check this question, Google is now providing official support for in-app notification for application update the full documentation can be found here

Use this : https://www.push-link.com/

Google Play will notify your users that the app has an update via the notification bar.
If you set up a notification system yourself, the likely result would be that, although the user is notified of an update sooner, when he/she goes to Google Play to install the update it will not yet be available. This is because there is a lag from the time you "publish" an app/update and the time until it appears on Play. Telling your users that there is an update when the update is unavailable would only lead to confusion and frustration.
My advice: stick with Google's update notification system and don't worry about trying to get users an update 15 minutes sooner.

Some people use Android Cloud-to-Device Messaging (C2DM) to notify their users of updates. I don't think I'd bother, since I think Google Play does a pretty good job of notifying me of updates already, and implementing C2DM adds a whole new dimension to writing an app (because it requires a server component). But maybe you want to offer your users a richer update notification than you get from Google Play.

#Davek804's answer above is wrong. android:versionCode is an integer value that represents the version of the application code, relative to other versions, so using "1.5b" there is incorrect. Use "15" (or "150") instead

Found a nice solution for your problem:
Let´s say you want to check for version updates manually on app start and notify your users for the new Update.
Step 1: Download android-market-api (not the .jar file, the full project!)
Step 2: After importing it to eclipse, write in your activity the following code:
MarketService ms = new MarketService(activity);
ms.level(MarketService.REVISION).checkVersion();
now, we need to modify MarketService.java, because it seems to be broken.
Step 3: rewrite callback method and add the following methods
protected void callback(String url, JSONObject jo, AjaxStatus status){
if(jo == null) return;
String googlePlayversion = jo.optString("version", "0");
String smartphone_version = "";
PackageInfo pInfo;
try {
pInfo = act.getPackageManager().getPackageInfo(act.getPackageName(), 0);
smartphone_version = pInfo.versionName;
} catch (NameNotFoundException e) {}
boolean new_version_avaible = compare(smartphone_version, googlePlayversion);
if(new_version_avaible){
showUpdateDialog(jo);
}
}
private static boolean compare(String v1, String v2) {
String s1 = normalisedVersion(v1);
String s2 = normalisedVersion(v2);
int cmp = s1.compareTo(s2);
String cmpStr = cmp < 0 ? "<" : cmp > 0 ? ">" : "==";
System.out.printf("result: "+"'%s' %s '%s'%n", v1, cmpStr, v2);
if(cmpStr.contains("<")){
return true;
}
if(cmpStr.contains(">")||cmpStr.contains("==")){
return false;
}
return false;
}
public static String normalisedVersion(String version) {
return normalisedVersion(version, ".", 4);
}
public static String normalisedVersion(String version, String sep, int maxWidth) {
String[] split = Pattern.compile(sep, Pattern.LITERAL).split(version);
StringBuilder sb = new StringBuilder();
for (String s : split) {
sb.append(String.format("%" + maxWidth + 's', s));
}
return sb.toString();
}
If you want to test it, modify googlePlayversion string to a higher version than your local one.
The source comparison method I used is from How do you compare two version Strings in Java?

There is also a very good approach for checking version and give user in app notification or when you want to forcefully update the application if you can decide the first connection of your app with the server.In the response of the first request you can send the current version of app stored on your server and then on client end you can take the appropriate action.
Advantages of this approach-:
1-No extra request for version no.
2-It is also applicable if you are downloading the app other than the google playstore.
3-you can also use this idea if you want to check the version at particular operation of your app ex- transaction(if you add a new payment gateway.)

Don't know if you want to walk extra miles. You can try out google appengine, which serve version number for your app and let you android app check the appengine to see if there is a new version when the application is launched. That way, it does not matter if your app is in google play market nor amazon app store nor if it is installed on the phone without those two via sideloading. It is not very hard to setup appengine just for serving your application version in json. Replace "Hello World" string with your app version name ...

This can be using a simple webservice just this is one of the way to acheive.
i.e., when ever the app launch hit that webservice with the current version of the user app and on the server you need to check whether any new version is available or not(Must maintain the newest version of the app) and send the corresponding response to the user. If any newer version is available prompt the user to download the newest version of the application and if no newest version is available then allow the user to continue.
Hope so atleast something must be useful to you.

There are two models that are basically used to tackle the issue.
Pull Based
Push Based
Its depends on the architecture or design of particular system that determines whether pull based or push mechanism is used.
For pull based model you just make one http request to concerned server regarding the new version of application. The current application version no can be saved in SQLLite in android application. This can be given to server and new version can be checked against it at the server.
For push mechanism you can use C2DM push notification service.. details of which are given at http://code.google.com/android/c2dm/

Generally when you upload a new application to Google play most users get a notification about an update, some will have the app automatically downloaded to their device, depending on the settings they have.
If you seriously want to make a notification from your app to ask them to update (so that everyone gets the notification, whatever their Google play settings are, then you will have to make a web service which returns the number of the newest version. You can then compare that inside your app and post a notification. You could use Google App Engine ( https://developers.google.com/appengine/) because that works with eclipse and java, which you probably already have.
I would not recommend this approach as it creates a lot of work for you to provide something that most users have already got.

i think this is too late but it can be help some one
public enum AppVersionUpgradeNotifier {
INSTANCE;
private static final String TAG = "AppVersionUpdateManager";
private static final String PREFERENCES_APP_VERSION = "pref_app_version_upgrade";
private static final String KEY_LAST_VERSION = "last_version";
private SharedPreferences sharedPreferences;
private VersionUpdateListener versionUpdateListener;
private boolean isInitialized;
public static synchronized void init(Context context, VersionUpdateListener versionUpdateListener) {
if (context == null || versionUpdateListener == null) {
throw new IllegalArgumentException(TAG + " : Context or VersionUpdateListener is null");
}
if (!INSTANCE.isInitialized) {
INSTANCE.initInternal(context, versionUpdateListener);
} else {
Log.w(TAG, "Init called twice, ignoring...");
}
}
private void initInternal(Context context, VersionUpdateListener versionUpdateListener) {
this.sharedPreferences = context.getSharedPreferences(PREFERENCES_APP_VERSION, Context.MODE_PRIVATE);
this.versionUpdateListener = versionUpdateListener;
this.isInitialized = true;
checkVersionUpdate();
}
private void checkVersionUpdate() {
int lastVersion = getLastVersion();
int currentVersion = getCurrentVersion();
if (lastVersion < currentVersion) {
if (versionUpdateListener.onVersionUpdate(currentVersion, lastVersion)) {
upgradeLastVersionToCurrent();
}
}
}
private int getLastVersion() {
return sharedPreferences.getInt(KEY_LAST_VERSION, 0);
}
private int getCurrentVersion() {
return BuildConfig.VERSION_CODE;
}
public void upgradeLastVersionToCurrent() {
sharedPreferences.edit().putInt(KEY_LAST_VERSION, getCurrentVersion()).apply();
}
public interface VersionUpdateListener {
boolean onVersionUpdate(int newVersion, int oldVersion);
}
}
use it on
public class MyApplication extends Application implements AppVersionUpgradeNotifier.VersionUpdateListener {
#Override
public void onCreate() {
super.onCreate();
AppVersionUpgradeNotifier.init(this,this);
}
#Override
public boolean onVersionUpdate(int newVersion, int oldVersion) {
//do what you want
return true;
}
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
android:versionCode="1.5b"
android:versionName="1.5b">
When you re-upload your app to Google Play, if these two attributes have been changed from the previous upload, Google Play will automatically send notifications to users who have installed your app. This is the AndroidManifest file.