Develop Reference

Android - How to detect "Power Save mode" in Huawei or other devices? [duplicate]

I am currently implement a feature where the users are requested to ignore battery optimisation for the application. The reason for doing so, is that the main functionality of the application is unfortunately drastically affected by power save mode.
To achieve my goal, I prompt the users by creating an Intent and setting the Action to ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS.
Although, before firing the Intent, I both check for isPowerSaveMode() and isIgnoringBatteryOptimizations() to ensure that I don't prompt the users when power save mode is not enabled; which is a requirement for the feature. The way I do so is by:
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
boolean isPowerSaveMode = pm.isPowerSaveMode(); // always returns false for Huawei devices
This works fine for the most devices, but for Huawei devices, isPowerSaveMode() always returns false. Consequently, since the preconditions fail, the prompt is never shown.
Has anyone else possibly encountered this issue? If so, what did you do to solve it?
As a note, the same issue is also present in the Xamarin.Android SDK.

Some Chinese ROM like Huawei or Xiaomi didn't implement the standard API for power save mode query. But like other system settings, a state flag will be saved to database when user turn power save mode on/off.
So we can utilize this state flag to solve the compatibility problem. Also a specific intent will send by system when toggle power save mode, we can listen this intent action to monitor power save mode changing.
Below is the detailed kotlin code implementation for Huawei or Xiaomi devices.
object PowerManagerCompat {
private const val TAG = "PowerManagerCompat"
interface PowerSaveModeChangeListener {
/**
* will be called when power save mode change, new state can be query via [PowerManagerCompat.isPowerSaveMode]
*/
fun onPowerSaveModeChanged()
}
private val POWER_SAVE_MODE_VALUES = mapOf(
"HUAWEI" to 4,
"XIAOMI" to 1
)
private val POWER_SAVE_MODE_SETTING_NAMES = arrayOf(
"SmartModeStatus", // huawei setting name
"POWER_SAVE_MODE_OPEN" // xiaomi setting name
)
private val POWER_SAVE_MODE_CHANGE_ACTIONS = arrayOf(
"huawei.intent.action.POWER_MODE_CHANGED_ACTION",
"miui.intent.action.POWER_SAVE_MODE_CHANGED"
)
private const val monitorViaBroadcast = true
/**
* Monitor power save mode change, only support following devices
* * Xiaomi
* * Huawei
*/
fun monitorPowerSaveModeChange(context: Context, powerSaveModeChangeListener: PowerSaveModeChangeListener) {
if (Build.MANUFACTURER.toUpperCase(Locale.getDefault()) !in POWER_SAVE_MODE_VALUES.keys) {
Log.w(TAG, "monitorPowerSaveModeChange: doesn't know how to monitor power save mode change for ${Build.MANUFACTURER}")
}
if (monitorViaBroadcast) {
context.registerReceiver(object : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
powerSaveModeChangeListener.onPowerSaveModeChanged()
}
}, IntentFilter().also {
for (a in POWER_SAVE_MODE_CHANGE_ACTIONS) {
it.addAction(a)
}
})
} else {
val contentObserver = object : ContentObserver(null) {
override fun onChange(selfChange: Boolean) {
super.onChange(selfChange)
powerSaveModeChangeListener.onPowerSaveModeChanged()
}
}
for (name in POWER_SAVE_MODE_SETTING_NAMES) {
context.contentResolver.registerContentObserver(
Uri.parse("content://settings/system/${name}"), false, contentObserver)
}
}
}
/**
* Check the system is currently in power save mode
* #see [PowerManager.isPowerSaveMode]
*/
fun isPowerSaveMode(context: Context): Boolean {
if (Build.MANUFACTURER.toUpperCase(Locale.getDefault()) in POWER_SAVE_MODE_VALUES.keys) {
return isPowerSaveModeCompat(context)
}
val powerManager = context.getSystemService(Context.POWER_SERVICE) as? PowerManager
return powerManager?.isPowerSaveMode ?: false
}
private fun isPowerSaveModeCompat(context: Context): Boolean {
for (name in POWER_SAVE_MODE_SETTING_NAMES) {
val mode = Settings.System.getInt(context.contentResolver, name, -1)
if (mode != -1) {
return POWER_SAVE_MODE_VALUES[Build.MANUFACTURER.toUpperCase(Locale.getDefault())] == mode
}
}
return false
}
}

Each oem modifies the SDK to suit their needs . Huawei devices don't use the default power saver function , instead they use something called "Protected apps". Protected apps are set of apps which are allowed to run even when the screen is turned off. So that's the reason it always returns false . Its better to throw a intent to protected apps screen but there is no way to know if your app is added to the protected apps list.
What is protected apps ?

I've found a way to manually request current Huawei Power Mode state and receive change events by adding a custom action to the IntentFilter:
(Note tested only on Huawei P20 Lite (ANE-LX3) # EMUI 8.0.0)
// Manually request Power Save Mode:
public Boolean isPowerSaveMode(Context context) {
if (Build.MANUFACTURER.equalsIgnoreCase("Huawei")) {
return isPowerSaveModeHuawei(context);
} else {
return isPowerSaveModeAndroid(context);
}
}
#TargetApi(21)
private Boolean isPowerSaveModeAndroid(Context context) {
boolean isPowerSaveMode = false;
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
if (pm != null) isPowerSaveMode = pm.isPowerSaveMode();
}
return isPowerSaveMode;
}
private Boolean isPowerSaveModeHuawei(Context context) {
try {
int value = android.provider.Settings.System.getInt(context.getContentResolver(), "SmartModeStatus");
return (value == 4);
} catch (Settings.SettingNotFoundException e) {
// Setting not found? Return standard android mechanism and hope for the best...
return isPowerSaveModeAndroid(context);
}
}
// Listening for changes in Power Save Mode
public void startMonitoringPowerSaveChanges(Context context) {
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
if (mPowerSaveChangeReceiver != null) {
return;
}
// Register for PowerSaver change updates.
mPowerSaveChangeReceiver = new PowerSaveChangeReceiver();
// Registering the receiver
IntentFilter filter = new IntentFilter();
filter.addAction(PowerManager.ACTION_POWER_SAVE_MODE_CHANGED);
// Add custom huawei action
filter.addAction("huawei.intent.action.POWER_MODE_CHANGED_ACTION");
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
filter.addAction(android.provider.Settings.ACTION_IGNORE_BATTERY_OPTIMIZATION_SETTINGS);
}
context.registerReceiver(mPowerSaveChangeReceiver, filter);
}
}
#TargetApi(21)
class PowerSaveChangeReceiver extends BroadcastReceiver {
public void onReceive(Context context, Intent intent) {
boolean isPowerSaveMode = false;
// Oh, Huawei...why don't you play by the same rules as everyone else?
if (intent.getAction().equals("huawei.intent.action.POWER_MODE_CHANGED_ACTION")) {
Bundle extras = intent.getExtras();
if ((extras != null) && extras.containsKey("state")) {
int state = intent.getExtras().getInt("state");
isPowerSaveMode = (state == 1); // ON=1; OFF=2
}
} else {
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
isPowerSaveMode = pm.isPowerSaveMode();
}
Log.d("MyTag", "[powersavechange] isPowerSaveMode? " + isPowerSaveMode);
}
}

I have faced new the same problem while inmplementation handheld and wearable devices.
The only solution I found is to disable battery saver mode for all apps.
I would suggest to detect the result of your methods after disabling such mode for all apps. This bug appear only on Huawei. Awful vendor.

private void isPowerSaveModeHuaweiXiaomi(){
if (Build.MANUFACTURER.equalsIgnoreCase("Xiaomi")) {
try {
int value = android.provider.Settings.System.getInt(getContext().getContentResolver(), "POWER_SAVE_MODE_OPEN");
} catch (Settings.SettingNotFoundException e) {
Log.d("Valor modo bateria:", "Error");
}
}else if (Build.MANUFACTURER.equalsIgnoreCase("Huawei")){
try {
int value = android.provider.Settings.System.getInt(getContext().getContentResolver(), "SmartModeStatus");
} catch (Settings.SettingNotFoundException e) {
Log.d("Valor modo bateria:", "Error");
}
}
}

On new Huawei devices such as Huawei P30 lite for instance the solution to this question is unknown as for now (27.12.2021). calling getInt with the key "SmartModeStatus" will throw a key unknown exception. Therefore the best we can do is the following.
private string HuaweiPowerSaveModeSettingsName = "SmartModeStatus";
private int HuaweiPowerSaveModeValue = 4;
public bool IsBatterySaverEnabled
=> Build.Manufacturer?.ToUpper() == "HUAWEI" ? GetIsBatterySaverEnabledHuawei() : GetIsBatterySaverEnabledAllDevicesExceptHuawei();
private bool GetIsBatterySaverEnabledAllDevicesExceptHuawei()
{
return PowerManager.FromContext(Application.Context)?.IsPowerSaveMode ?? false;
}
private bool GetIsBatterySaverEnabledHuawei()
{
try
{
var mode = Settings.System.GetInt(Application.Context.ContentResolver, HuaweiPowerSaveModeSettingsName);
return HuaweiPowerSaveModeValue == mode;
} catch (Exception e)
{
return GetIsBatterySaverEnabledAllDevicesExceptHuawei();
}
}

For huawei vtr-al00, SmartModeStatus 1 could be ultra save mode or the normal mode. I've used reflection to handle this.
final int _HX = Build.MANUFACTURER.equalsIgnoreCase("Xiaomi")?2
:Build.MANUFACTURER.equalsIgnoreCase("Huawei")?1
:0;
// “No Kotlin”
private boolean isPowerSaveModeCompat(){
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP
&& powerManager.isPowerSaveMode()) { // hopefully...
return true;
}
if (_HX==0) {
return false;
}
else if (_HX==1) {
try {
int value = Settings.System.getInt(getContentResolver(), "SmartModeStatus");
CMN.debug("isPowerSaveModeCompat::huawei::"+value);
// value 4==Save Mode; 1==Ultra Save Mode==Normal Mode;
// ( tested on my huawei vtr-al00 )
if(value==4) {
return true;
}
if(value==1) {
// what if Ultra save mode???
// https://github.com/huaweigerrit
// https://github.com/SivanLiu/HwFrameWorkSource
// https://stackoverflow.com/questions/2641111/where-is-android-os-systemproperties
// Class sysProp= Class.forName("android.os.SystemProperties");
// Method sysProp_getBool = sysProp.getMethod("getBoolean", new Class[]{String.class, boolean.class});
// Object[] parms = new Object[]{"sys.super_power_save", false};
// CMN.debug("huawei::UltraPowerSave::", sysProp_getBool.invoke(null, parms));
// CMN.debug("huawei::UltraPowerSave::", getSystemProperty("sys.super_power_save"));
return "true".equals(getSystemProperty("sys.super_power_save"));
}
} catch (Exception e) {
CMN.debug(e);
}
}
else if (_HX==2){
try {
int value = Settings.System.getInt(getContentResolver(), "POWER_SAVE_MODE_OPEN");
CMN.debug("isPowerSaveModeCompat::xiaomi::"+value);
// dont have xiaomi. not tested.
return value==1;
} catch (Exception e) {
CMN.debug(e);
}
}
// else if...
return false;
}
// https://stackoverflow.com/questions/9937099/how-to-get-the-build-prop-values
public String getSystemProperty(String key) {
String value = null;
try {
value = (String) Class.forName("android.os.SystemProperties")
.getMethod("get", String.class).invoke(null, key);
} catch (Exception e) {
e.printStackTrace();
}
return value;
}
Java is just shorter kotlin, even with so many comments and dirty tests!
:)

Android Test - function with queryIntentActivities return empty list

so i'm working on a UI test class, the problem i'm facing is that the function triggered by my UI test contains a check with queryIntentActivities() and this function is returning me an empty list and i can't figure why. Any idea ?
The test class :
#RunWith(AndroidJUnit4::class)
class TestMyActivity {
private lateinit var scenario: ActivityScenario<MyActivity>
#Before
fun setUp() {
scenario = ActivityScenario.launch(MyActivity::class.java)
}
#Test
fun testMybutton() {
scenario.onActivity {
onView(withId(R.id.my_recyclerview))
.perform(
RecyclerViewActions.actionOnItem<ViewHolder>(
hasDescendant(withText("text that match")),
click()
)
)
intended(hasAction(Intent.ACTION_DIAL))
}
}
The function called on click :
public static void startCall(Context context, String phoneNumber) {
try {
Uri phoneUri = Uri.parse("tel:" + phoneNumber);
Intent intent = new Intent(Intent.ACTION_DIAL);
intent.setData(phoneUri);
// Check if some app in device can handle this intent ( = check if
// device
// can use
// dial feature, example : tablet can't)
PackageManager manager = context.getPackageManager();
List<ResolveInfo> infos = manager.queryIntentActivities(intent, 0);
if (infos.size() > 0) {
context.startActivity(intent);
}
} catch (Exception e) {
e.printStackTrace();
}
}
Thanks

Get isActiveNetworkMetered and isDefaultNetworkActive in API 29

After connectivityManager.getActiveNetworkInfo() got deprecated in API 29, it was quite a struggle to put together a network monitoring function that would also distinguish metered (cell) vs WiFi connection.
The problems I faced were 2:
connectivityManager.isActiveNetworkMetered() -- when both WiFi and Mobile data were on, it returned true (at least on my emulator, and I couldn't check on a device). When only WiFi was on, it returned false, as expected.
connectivityManager.isDefaultNetworkActive() -- it would always be active even if WiFi and Mobile were off.
The only way I found to work around this is via (1) onCapabilitiesChanged() and (2) getActiveNetwork()==null. The code is pasted below.
Do you know if there are other ways to do it? The whole implementation seems cumbersome, and the internet is full of deprecated examples.
Thanks
private static void monitorNetworks(){
NetworkRequest.Builder builder = new NetworkRequest.Builder();
connectivityManager.registerNetworkCallback(
builder.build(),
ncb = new ConnectivityManager.NetworkCallback() {
#Override
public void onAvailable(Network network) {
scanAndSend();
}
#Override
public void onLost(Network network) {
scanAndSend();
}
#Override
public void onUnavailable(){
scanAndSend();
}
#Override
public void onCapabilitiesChanged (Network network,
NetworkCapabilities networkCapabilities){
boolean metered = !networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_NOT_METERED);
Log.d(TAG, "NET_CAPABILITY_NOT_METERED: " +
String.valueOf(networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_NOT_METERED)));
sendMetered(metered);
}
}
);
}
private static void scanAndSend(){
boolean is_connected = false;
if(connectivityManager.getActiveNetwork()==null) is_connected = false;
else is_connected = true;
sendConnectivityIntent(IS_NETWORK_AVAILABLE, is_connected);
}
private static void sendMetered(boolean metered) {
sendIntent(IS_NETWORK_METERED, metered);
}
private static void sendIntent(String val_name, boolean val) {
Intent intent = new Intent();
intent.setAction(CONNECTIVITY_ACTION);
intent.putExtra(val_name, val);
context.sendBroadcast(intent);
}

Android Java USB serial communication plugin for Unity not running

I created a Java plugin that utilizes the UsbManager devices to communicate with a specified serial device. I'm using Android Studio to run the plugin and can write to the proper device, but I don't understand how to integrate my code with Unity. I pass the Context in the constructor so I can create the UsbManager, but I don't know how to this in Unity or if there's another way to get the Context.
What's the proper way to pass the Context from Unity to my plugin? I'm also not sure if my function is working in Unity, because I don't know if permissions are needed for USB as well in the manifest file.
Unity Code:
void Start()
{
ajc = new AndroidJavaObject("com.company.dg.USBController");
int connected = ajc.Call<int>("startUSB");
}
Java Code:
public class USBController {
private Context context;
private static final String ACTION_USB_PERMISSION = "com.company.dg.USB_PERMISSION";
private final int BAUD_RATE = 19200;
private int bytesRead;
private byte[] readBuffer;
private UsbManager usbManager;
private UsbDeviceConnection connection;
private UsbSerialDevice serial;
private UsbDevice dg = null;
public USBController(Context context){
this.context = context;
}
public int startUSB(){
//usbManager = (UsbManager) context.getSystemService(context.USB_SERVICE);
HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
UsbDevice dg = null;
if(deviceList.size() == 0){
return -2;
}
// 1st and only device
dg = deviceList.values().iterator().next();
if(dg != null){
PendingIntent pi = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);
usbManager.requestPermission(dataglove, pi);
UsbDeviceConnection connection = usbManager.openDevice(dataglove);
UsbSerialDevice serial = UsbSerialDevice.createUsbSerialDevice(dg, connection);
serial.open();
serial.setBaudRate(BAUD_RATE);
serial.setDataBits(UsbSerialInterface.DATA_BITS_8);
serial.setStopBits(UsbSerialInterface.STOP_BITS_1);
serial.setParity(UsbSerialInterface.PARITY_NONE);
serial.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF);
serial.read(callback);
} else {
return -1;
}
return 0;
}
private UsbSerialInterface.UsbReadCallback callback = new UsbSerialInterface.UsbReadCallback() {
#Override
public void onReceivedData(byte[] data) {
bytesRead = data.length;
readBuffer = data;
}
};

What's the proper way to pass the Context from Unity to my plugin?
C# side:
Your USBController class has a constructor that takes Context as an argument. Before calling the startUSB function, obtain the Unity Context then send it to the constructor when you're creating an instance of USBController.
Get Unity Context:
AndroidJavaClass unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
AndroidJavaObject unityActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity");
AndroidJavaObject unityContext = unityActivity.Call<AndroidJavaObject>("getApplicationContext");
Send the Context to your Java code when creating an instance of it:
ajc = new AndroidJavaObject("com.bebopsensors.dg.USBController", unityContext);
Now, you can call your startUSB function:
int connected = ajc.Call<int>("startUSB");
Java Side:
In your startUSB function, you can now use the Context with the getSystemService. I noticed you commented that out. Note that the context.USB_SERVICE should be Context.USB_SERVICE. The c in Context should be capitalized.
public int startUSB()
{
usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
....
....
}
Don't know if permissions are needed for USB as well in the manifest
file.
Not really sure about that but I believe that calling the requestPermission function which you did should be enough to handle that. If this is not working then I suggest you test your Java program in Android only and Without Unity to see if it's working. If it works there, the solution I suggested should also work.

How to change Android O / Oreo / api 26 app language

I want to change the language of the app and this works fine until API 26.
For api > 25 I put Locale.setDefault(Locale.Category.DISPLAY, mynewlanglocale); before setContentView(R.layout.activity_main); but nothing changes.
The docs don't explain too much about this.

I had the same problem: since Android 8.0+ some parts of my app did't change their language anymore. Updating of both application and activity context helps me. Here is an example of MainActivity function:
private void setApplicationLanguage(String newLanguage) {
Resources activityRes = getResources();
Configuration activityConf = activityRes.getConfiguration();
Locale newLocale = new Locale(newLanguage);
activityConf.setLocale(newLocale);
activityRes.updateConfiguration(activityConf, activityRes.getDisplayMetrics());
Resources applicationRes = getApplicationContext().getResources();
Configuration applicationConf = applicationRes.getConfiguration();
applicationConf.setLocale(newLocale);
applicationRes.updateConfiguration(applicationConf,
applicationRes.getDisplayMetrics());
}

Yes in android Oreo localization is not working fine with updateconfiguration. But it is deprecated in android N itself. Instead of updateconfiguration use createconfiguration in each attachcontext. it is working fine for me. Try this...
In you activity add this..
#Override
protected void attachBaseContext(Context newBase) {
if(Build.VERSION.SDK_INT > Build.VERSION_CODES.N_MR1) {
super.attachBaseContext(MyContextWrapper.wrap(newBase, "ta"));
}
else {
super.attachBaseContext(newBase);
}
}
In MyContextWrapper.java
public static ContextWrapper wrap(Context context, String language) {
Resources res = context.getResources();
Configuration configuration = res.getConfiguration();
Locale newLocale = new Locale(language);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
configuration.setLocale(newLocale);
LocaleList localeList = new LocaleList(newLocale);
LocaleList.setDefault(localeList);
configuration.setLocales(localeList);
context = context.createConfigurationContext(configuration);
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
configuration.setLocale(newLocale);
context = context.createConfigurationContext(configuration);
} else {
configuration.locale = newLocale;
res.updateConfiguration(configuration, res.getDisplayMetrics());
}
return new ContextWrapper(context);
}

updateConfiguration is deprecated and you should use createConfigurationContext. I solved it this way:
#Override
protected void attachBaseContext(Context newBase) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
Configuration config = newBase.getResources().getConfiguration();
//Update your config with the Locale i. e. saved in SharedPreferences
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(newBase);
String language = prefs.getString(SP_KEY_LANGUAGE, "en_US");
Locale.setDefault(locale);
config.setLocale(new Locale(language));
newBase = newBase.createConfigurationContext(config);
}
super.attachBaseContext(newBase);
}

Updated For All android versions till Oreo
Create a class like this
public class LocaleUtils {
#Retention(RetentionPolicy.SOURCE)
#StringDef({ENGLISH, FRENCH, SPANISH})
public #interface LocaleDef {
String[] SUPPORTED_LOCALES = {ENGLISH, FRENCH, SPANISH};
}
public static final String ENGLISH = "en";
public static final String FRENCH = "fr";
public static final String SPANISH = "es";
public static void initialize(Context context) {
setLocale(context, ENGLISH);
}
public static void initialize(Context context, #LocaleDef String defaultLanguage) {
setLocale(context, defaultLanguage);
}
public static boolean setLocale(Context context, #LocaleDef String language) {
return updateResources(context, language);
}
private static boolean updateResources(Context context, String language) {
Locale locale = new Locale(language);
Locale.setDefault(locale);
Resources resources = context.getResources();
Configuration configuration = resources.getConfiguration();
context.createConfigurationContext(configuration);
configuration.locale = locale;
resources.updateConfiguration(configuration, resources.getDisplayMetrics());
return true;
}
}
Now when you select the language from your app, Save the language code in Shared Preference like below
private static SharedPreferences getDefaultSharedPreference(Context context) {
if (PreferenceManager.getDefaultSharedPreferences(Application.getInstance().getApplicationContext()) != null)
return PreferenceManager.getDefaultSharedPreferences(Application.getInstance().getApplicationContext());
else
return null;
}
public static void setSelectedLanguageId(String id){
final SharedPreferences prefs = getDefaultSharedPreference(Application.getInstance().getApplicationContext());
SharedPreferences.Editor editor = prefs.edit();
editor.putString("app_language_id", id);
editor.apply();
}
public static String getSelectedLanguageId(){
return getDefaultSharedPreference(Application.getInstance().getApplicationContext())
.getString("app_language_id", "en");
}
These three functions should be written inside a Utiltiy class(your preference). Then when you select the app language from the app, call the setSelectedLanguageId() function and pass the language id as parameter.
This way you have saved the selected language in your app. Now in your application class write a function like this
public void initAppLanguage(Context context){
LocaleUtils.initialize(context, PreferenceUtil.getSelectedLanguageId() );
}
Here the PreferenceUtil is my Utiltiy class. You should replace it with your utility class function.
You should also create a variable in your application class
private static Application applicationInstance;
and in your Application class's onCreate method, initialise applicationInstance to be the applications context like this
applicationInstance = this;
Now write a getter function in your application class
public static synchronized Application getInstance() {
return applicationInstance;
}
And now when you start your first activity, call this method in your activity's onCreate
Application.getInstance().initAppLanguage(this);
Remember that we are passing the activity's context to the initAppLanguage() function, not the application context. Passing the Application context won't make it work in Oreo(atleast for me).
So when you select the language try to restart your application completely.
You can acheive this by
Intent i = getBaseContext().getPackageManager().getLaunchIntentForPackage(getBaseContext().getPackageName());
startActivity(i);
Hope this helps you!

It is possible, however i would not recommend to set the language programatically
Android is designed so the System UI and your App have the same language, if you change it programmatically you would be fighting the system
Instead what you can do is enable multilanguage support by adding different strings.xml languages, this will change the language automatically
I reccommend reading through this Google Developers article:
Supporting Different Languages and Cultures
If you really need to change it programatically you can do the following
Locale locale = new Locale("en");
Locale.setDefault(locale);
Configuration config = context.getResources().getConfiguration();
config.setLocale(locale);
context.createConfigurationContext(config);
context.getResources().updateConfiguration(config, context.getResources().getDisplayMetrics());
On SDK >= 21, you need to call 'Resources.updateConfiguration()', otherwise resources will not be updated.
Hope it helps.

Here is complete solution worked for kitkat, Lollipop, Marshmallow, Nougat and Oreo too. Just follow all below step.
First create a java class like below
import android.content.Context;
import android.content.res.Configuration;
import java.util.Locale;
public class LocaleUtils {
public static void updateConfig(Context mContext, String sLocale) {
Locale locale = new Locale(sLocale);
Locale.setDefault(locale);
Configuration config = mContext.getResources().getConfiguration();
config.locale = locale;
mContext.getResources().updateConfiguration(config,
mContext.getResources().getDisplayMetrics());
}
}
Now add this snippet on Button click where you want to change locale
String lang="hi";//pass your language here
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(mContext);
SharedPreferences.Editor editor = preferences.edit();
editor.clear();
editor.putString("lang", lang");
editor.putBoolean("langSelected", true);
editor.apply();
LocaleUtils.updateConfig(mContext,lang);
Intent intent = mContext.getIntent();
mContext.overridePendingTransition(0, 0);
mContext.finish();
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
mContext.overridePendingTransition(0, 0);
mContext.startActivity(intent);
Finally paste the below code in Splash Activity or in Launching Activity.
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String lang = preferences.getString("lang", "");
boolean langSelected = preferences.getBoolean("langSelected", false);
SharedPreferences.Editor editor = preferences.edit();
if (langSelected) {
editor.clear();
editor.putString("lang", lang);
editor.putBoolean("langSelected", true);
editor.apply();
LocaleUtils.updateConfig(this,lang);
} else {
LocaleUtils.updateConfig(this, Locale.getDefault().getLanguage());
editor.clear();
editor.putString("lang", Locale.getDefault().getLanguage());
editor.putBoolean("langSelected", false);
editor.apply();
}

After use all solution in all sources finally i found my issue. That makes me angry for 2 days.
Everyone knows that in Android Oreo (API 26) we must use createConfigurationContext, But My problem is using Country name with local.
Replace
en_US with en
ar_AE with ar
fa_IR with fa
And my problem solved.
Hope to help someone

You need to use getApplicationContext() instead of getContext()