I'm having an app which is already live on play store and whole data of that app is stored in EncryptedSharedPreferences. I'm using androidx.security.crypto for the SharedPreferences. Now I'm going to have a new app on play store with different package name. So I want to access whole data of that app and transfer into new app. I tried using sharedId but it always returns null to me. Below I'm mentioning the custom shared preferences class what I'm using in an existing app.
class SharedPrefUtils(context: Context) {
private val keyGenParameterSpec = MasterKeys.AES256_GCM_SPEC
private val masterKeyAlias = MasterKeys.getOrCreate(keyGenParameterSpec)
private val PASS_KEY = context.getString(R.string.pass_key)
private val sharedPrefs = EncryptedSharedPreferences.create(
PASS_KEY,
masterKeyAlias,
context,
EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
)
So I want to know whether it's possible to access this type of data or not. If not, then what alternatives I can have.
Thanks.
I have a mutable list created in a viewmodel file that saves the data
//questions they cheated on
var cheatedList = mutableListOf<Int>(6)
I linked the viewmodel file with the file that has functions this way
private val quizViewModel : QuizViewModel by lazy {
ViewModelProviders.of(this).get(QuizViewModel::class.java)
}
it is working fine and i checked it. all i need from it is to save a content of Integers into a mutable list... I use this function to do so
showAnswerButton.setOnClickListener {
val answerText = when{
answerIsTrue -> R.string.true_button
else -> R.string.false_button
}
answerTextView.setText(answerText)
//create a function to return the result to MainActivity
setAnswerShownResult(true)
cheaterStatus = true
quizViewModel.cheatedList.add(currentIndex)
println(quizViewModel.cheatedList)
}
the good news is, it saves the index into the list... the bad news is once i move back to another activity, the list is destroyed and nothing is saved in it anymore...
how can i keep the mutablelist saved even if i closed the activity?
If you want the data to be saved even after closing the application and re opening it (Not temporary closing) you can use local storage like Room to save the data...
But if you only want to save the data in a session then as Tenfour04 said you can use a activity and multiple fragment and use a single viewmodel pattern to save.....
I am using EncryptedSharedPreferences to store user information locally (see this if you are not familiar). I have implemented AutoBackUp with BackUp rules. I backed up the preferences, cleared data on my app, and attempted to restore the data (following the steps outlined for backup and restore).
Looking at Device File Explorer in Android Studio, I can confirm that my Preferences file is being restored (it is properly named and there is encrypted data in it). However, my app functions as if the preferences file does not exist.
What am I missing?
Preferences code:
class PreferenceManager(context: Context) {
companion object {
private const val KEY_STORE_ALIAS = "APP_KEY_STORE"
private const val privatePreferences = "APP_PREFERENCES"
}
// See https://developer.android.com/topic/security/data#kotlin for more info
private val sharedPreferences = EncryptedSharedPreferences.create(
privatePreferences,
KEY_STORE_ALIAS,
context,
EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
)
init {
//val all = sharedPreferences.all
//for (item in all) {
//Log.e("PREFERENCES", "${item.key} - ${item.value}")
//}
}
#SuppressLint("ApplySharedPref")
fun clear() {
// Normally you want apply, but we need the changes to be done immediately
sharedPreferences.edit().clear().commit()
}
fun readBoolean(key: String, defaultValue: Boolean): Boolean {
return sharedPreferences.getBoolean(key, defaultValue)
}
fun readDouble(key: String): Double {
return sharedPreferences.getFloat(key, 0f).toDouble()
}
fun readString(key: String): String {
return sharedPreferences.getString(key, "")!!
}
fun removePreference(key: String) {
sharedPreferences.edit().remove(key).apply()
}
fun writeBoolean(key: String, value: Boolean) {
sharedPreferences.edit().putBoolean(key, value).apply()
}
fun writeDouble(key: String, value: Double) {
sharedPreferences.edit().putFloat(key, value.toFloat()).apply()
}
fun writeString(key: String, value: String) {
sharedPreferences.edit().putString(key, value).apply()
}
}
I am not implementing a BackupAgent currently.
From my understanding Jetpack Security relies on keys that are generated on the device hardware, and so it is that you cannot rely on that the original key is still there after a backup restore (think about changed devices).
Encryption is only as secure as the security of the key, and as long as it cannot leave the Keystore or the device, backup and restore cannot work automatically (without user interaction).
My approach (1) would be that you ask the user for a password, encrypt your regular shared preferences based on that password (maybe with another encryption library: for example https://github.com/iamMehedi/Secured-Preference-Store), and save the password with encryptedsharedpreferences from Jetpack. After restore of the backup ask the user for the password, save it again with Jetpack and decrypt the regular SharedPreferences.
That way even when the hardware keystore changes, you can restore the backup. The disadvantage is, that the user needs to remember a password.
I follow this approach with my app, just not with sharedpreferences (they are not sensible in my use case), but with the app database.
Another approach (2) would be to check for encrypted backups (available from Pie on), if you are only concerned about backups in the cloud. With that approach you don't encrypt the sharedpreferences locally, but the backups are encrypted by default. If you need local encryption, this approach is not for you, but the advantage is, that the user must only type in his/her lockscreen password on restore of the backups and after that everything gets restored without further user interaction.
A combination is also thinkable and is preferrable, if you can live without local encryption: Approach 1 for pre-9 and Approach 2 for post-9.
As #Floj12 mentioned EncryptedSharedPreferences use Keystore and you cannot back up the Keystore, so when your encrypted data will be restored you won't be able to decrypt it.
This is very sad that Google force two things that don't work together. Keystore on Android doesn't have a backup option like Keychain on iOS.
Here I will give you more option how can you backup the data:
Store user data one backend
Use a user-stored token to decrypt the backup
Have a static password for all apps
Export backup manually by the user in settings
I wrote about it more here:
https://medium.com/#thecodeside/android-auto-backup-keystore-encryption-broken-heart-love-story-8277c8b10505
I am trying to have this new feature working but I keep getting an empty database. There is not much documentation and the articles on medium are not detailed enough.
Using the debugImplementation com.amitshekhar.android:debug-db:1.0.6 plugin to look into my database and manually add an entry to it.
After doing so I download the database.
The file itself is not a *.db file but I change the name and put the .db extension (I have tried both with and without).
I add it to my assets folder and on my databasebuilder I add a .createFromAsset with the path so that I can use the database.
When restarting the app (deleting and reinstalling) I find that is it not pre populated.
What exactly am I doing wrong?
This is how I create the database. There is nothing special with it.
single(createdAtStart = true) {
Room.databaseBuilder(
get(),
CountryDatabase::class.java,
"country_database"
).createFromAsset("database/country_database.db").build()
}
single(createdAtStart = true) {
get<CountryDatabase>().countryDao()
}
#Database(entities = [LocalCountryData::class], version = 4)
abstract class CountryDatabase : RoomDatabase() {
abstract fun countryDao(): CountryDao
}
#Entity(tableName = "countries")
data class LocalCountryData(
#PrimaryKey
val country_name: String,
val country_short_code: String,
val regions_name: String,
val regions_short_code: String
)
When restarting the app I find that is it not pre populated.
createFromAssets will only be invoked and copy the database from the database folder of the assets folder if there is no existing database.
Rather than restarting the App, you should either :-
delete the App's data or
uninstall the App
and then run the App.
I recently coded an Android app. It's just a simple app that allows you to keep score of a basketball game with a few simple counter intervals. I'm getting demand to add a save feature, so you can save your scores and then load them back up. Currently, when you stop the app, your data is lost. So what I was wondering is what I would have to add to have the app save a label (score) and then load it back up. Thanks guys sorry I don't know much about this stuff.
You have two options, and I'll leave selection up to you.
Shared Preferences
This is a framework unique to Android that allows you to store primitive values (such as int, boolean, and String, although strictly speaking String isn't a primitive) in a key-value framework. This means that you give a value a name, say, "homeScore" and store the value to this key.
SharedPreferences settings = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
SharedPreferences.Editor editor = settings.edit();
editor.putInt("homeScore", YOUR_HOME_SCORE);
// Apply the edits!
editor.apply();
// Get from the SharedPreferences
SharedPreferences settings = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
int homeScore = settings.getInt("homeScore", 0);
Internal Storage
This, in my opinion, is what you might be looking for. You can store anything you want to a file, so this gives you more flexibility. However, the process can be trickier because everything will be stored as bytes, and that means you have to be careful to keep your read and write processes working together.
int homeScore;
byte[] homeScoreBytes;
homeScoreBytes[0] = (byte) homeScore;
homeScoreBytes[1] = (byte) (homeScore >> 8); //you can probably skip these two
homeScoreBytes[2] = (byte) (homeScore >> 16); //lines, because I've never seen a
//basketball score above 128, it's
//such a rare occurance.
FileOutputStream outputStream = getApplicationContext().openFileOutput(FILENAME, Context.MODE_PRIVATE);
outputStream.write(homeScoreBytes);
outputStream.close();
Now, you can also look into External Storage, but I don't recommend that in this particular case, because the external storage might not be there later. (Note that if you pick this, it requires a permission)
OP is asking for a "save" function, which is more than just preserving data across executions of the program (which you must do for the app to be worth anything.)
I recommend saving the data in a file on the sdcard which allows you to not only recall it later, but allows the user to mount the device as an external drive on their own computer and grab the data for use in other places.
So you really need a multi-point system:
1) Implement onSaveInstanceState(). In this method, you're passed a Bundle, which is basically like a dictionary. Store as much information in the bundle as would be needed to restart the app exactly where it left off. In your onCreate() method, check for the passed-in bundle to be non-null, and if so, restore the state from the bundle.
2) Implement onPause(). In this method, create a SharedPreferences editor and use it to save whatever state you need to start the app up next time. This mainly consists of the users' preferences (hence the name), but anything else relavent to the app's start-up state should go here as well. I would not store scores here, just the stuff you need to restart the app. Then, in onCreate(), whenever there's no bundle object, use the SharedPreferences interface to recall those settings.
3a) As for things like scores, you could follow Mathias's advice above and store the scores in the directory returned in getFilesDir(), using openFileOutput(), etc. I think this directory is private to the app and lives in main storage, meaning that other apps and the user would not be able to access the data. If that's ok with you, then this is probably the way to go.
3b) If you do want other apps or the user to have direct access to the data, or if the data is going to be very large, then the sdcard is the way to go. Pick a directory name like com/user1446371/basketballapp/ to avoid collisions with other applications (unless you're sure that your app name is reasonably unique) and create that directory on the sdcard. As Mathias pointed out, you should first confirm that the sdcard is mounted.
File sdcard = Environment.getExternalStorageDirectory();
if( sdcard == null || !sdcard.isDirectory()) {
fail("sdcard not available");
}
File datadir = new File(sdcard, "com/user1446371/basketballapp/");
if( !datadir.exists() && !datadir.mkdirs() ) {
fail("unable to create data directory");
}
if( !datadir.isDirectory() ) {
fail("exists, but is not a directory");
}
// Now use regular java I/O to read and write files to data directory
I recommend simple CSV files for your data, so that other applications can read them easily.
Obviously, you'll have to write activities that allow "save" and "open" dialogs. I generally just make calls to the openintents file manager and let it do the work. This requires that your users install the openintents file manager to make use of these features, however.
In onCreate:
SharedPreferences sharedPref = getSharedPreferences("mySettings", MODE_PRIVATE);
String mySetting = sharedPref.getString("mySetting", null);
In onDestroy or equivalent:
SharedPreferences sharedPref = getSharedPreferences("mySettings", MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("mySetting", "Hello Android");
editor.commit();
Use SharedPreferences, http://developer.android.com/reference/android/content/SharedPreferences.html
Here's a sample:
http://developer.android.com/guide/topics/data/data-storage.html#pref
If the data structure is more complex or the data is large, use an Sqlite database; but for small amount of data and with a very simple data structure, I'd say, SharedPrefs will do and a DB might be overhead.
There is a lot of options to store your data and Android offers you to chose anyone
Your data storage options are the following:
Shared Preferences
Store private primitive data in key-value pairs.
Internal Storage
Store private data on the device memory.
External Storage
Store public data on the shared external storage.
SQLite Databases
Store structured data in a private database.
Network Connection
Store data on the web with your own network server
Check here for examples and tuto
2021 Answer
Old question but in 2021 you can use several things to save data.
1. Using local database - Room Library
Room is a library that let you store data in the internal SqlLite database that come with your Android device, it's a local database. It's easy and really powerful.
https://developer.android.com/training/data-storage/room
2. Using a remote database - Firebase / Your own database implementation
You can use Firebase services or your own database implementation on your server to remote store your data, that way you could access the data throw multiple devices.
https://firebase.google.com/docs/firestore
3. Storing a local file
You can store all information in a local file saved in the device's external storage, using maybe a .txt file with a \n as data separator. That option looks really "caveman" in 2021.
https://stackoverflow.com/a/14377185/14327871
4. Using SharedPreferences
As many people pointed you can also use the sharedPreferences to store little information as pair of key - value, it's useful for example when saving user preferences across a session.
https://developer.android.com/training/data-storage/shared-preferences?hl=en
For the OP case I would suggest using the 1st or 2nd option.
Shared preferences:
android shared preferences example for high scores?
Does your application has an access to the "external Storage Media". If it does then you can simply write the value (store it with timestamp) in a file and save it. The timestamp will help you in showing progress if thats what you are looking for. {not a smart solution.}
You can store your scores and load them back easily! by using this method
Use this library Paper Db
Add this library on your app:
implementation 'io.github.pilgr:paperdb:2.7.1'
and then initialize it once in the activity onCreate() you are storing:
Paper.init(context)
create a key to store your scores
int myScore=10;
Paper.book().write("scores", myScore);
and get the value of the score :
int mySavedScores=Paper.book().read("scores");
that's It!!! now you can save and access the value even application is closed
and refer the documentation for more methods and information,
it's a Good habit to read the documentation.
Please don't forget one thing - Internal Storage data are deleted when you uninstall the app. In some cases it can be "unexpected feature". Then it's good to use external storage.
Google docs about storage - Please look in particular at getExternalStoragePublicDirectory
Quick answer:
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
Boolean Music;
public static final String PREFS_NAME = "MyPrefsFile";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//restore preferences
SharedPreferences settings = this.getSharedPreferences(PREFS_NAME, 0);
Music = settings.getBoolean("key", true);
}
#Override
public void onClick() {
//save music setup to system
SharedPreferences settings = this.getSharedPreferences(PREFS_NAME, 0);
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean("key", Music);
editor.apply();
}
}
In my opinion db4o is the easiest way to go.
Here you can find a tutorial:
http://community.versant.com/documentation/reference/db4o-7.12/java/tutorial/
And here you can download the library:
http://www.db4o.com/community/download.aspx?file=db4o-8.0-java.zip
(Just put the db4o-8.0...-all-java5.jar in the lib directory into your project's libs folder.
If there is no libs folder in you project create it)
As db4o is a object oriented database system you can directly save you objects into the database and later get them back.
use this methods to use sharedPreferences very easily.
private val sharedPreferences = context.getSharedPreferences("myPreferences", Context.MODE_PRIVATE)
fun put(key: String, value: String) = sharedPreferences.edit().putString(key, value).apply()
fun put(key: String, value: Int) = sharedPreferences.edit().putInt(key, value).apply()
fun put(key: String, value: Float) = sharedPreferences.edit().putFloat(key, value).apply()
fun put(key: String, value: Boolean) = sharedPreferences.edit().putBoolean(key, value).apply()
fun put(key: String, value: Long) = sharedPreferences.edit().putLong(key, value).apply()
fun getString(key: String, defaultValue: String? = null): String? = sharedPreferences.getString(key, defaultValue)
fun getInt(key: String, defaultValue: Int = -1): Int = sharedPreferences.getInt(key, defaultValue)
fun getFloat(key: String, defaultValue: Float = -1F): Float = sharedPreferences.getFloat(key, defaultValue)
fun getBoolean(key: String, defaultValue: Boolean = false): Boolean = sharedPreferences.getBoolean(key, defaultValue)
fun getLong(key: String, defaultValue: Long = -1L): Long = sharedPreferences.getLong(key, defaultValue)
fun clearAll() = sharedPreferences.edit().clear().apply()
put them in a class and get context in its constructor.