Feature app-defined language implementation

[tanaynigam]

Description

Line Summary

Add feature app-defined language implementation. A user can define their own language setting to be used by OneSignal-SDK

Details

• Add LanguageContext, LanguageProviderAppDefined and LanguageProviderDevice class
• LanguageContext uses strategy pattern to retrieve either app-defined or device language
• LanguageProviderAppDefined retrieves app-defined language
• LanguageProviderDevice retrieves device language
• Add LanguageProvider interface that defines method getLanguage
• Add network call to OneSignal.setLanguage method that saves app-defined language to OneSignal.preferences
• Remove OSUtils.getCorrectedLanguage method
• Replace LanguageProviderDevice.getLanguage method with implementation from OSUtils.getCorrectedLanguage
• Add OSSharedPreferences dependency injection to LanguageContext and LanguageProviderAppDefined constructors
• Inject OneSignal.preferences into LanguageContext initialization
• Add LanguageContext dependency injection in OSInAppMessageController, OSInAppMessageControllerFactory and OSInAppMessageDummyController constructors
• Add LanguageContext.getLanguage to OSInAppMessageController.variantIdForMessage
• Add singleton pattern to LanguageContext class
• Add getLanguage method to NotificationChannelManager.createChannel using LanguageContext instance

Test

• Add MainOneSignalClassRunner testSetLanguageOnPlayerCreate, testSetLanguagePUTRequest, testSetLanguageOnSession unit tests
• Test device using button click to call OneSignal.setLanguage to set it to language different from language defined by the device. OneSignal app dashboard reflects the language set using OneSignal.setLanguage

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This change is 

[jkasten2]

Left a few comments in the code with some nits line-by-line:

Also a number of tests are failing due to null errors:

1. Missing LanguageContext for IAMs in tests. https://travis-ci.com/github/OneSignal/OneSignal-Android-SDK/builds/226256046#L3605-L3611
2. Some notification channel tests failing. https://travis-ci.com/github/OneSignal/OneSignal-Android-SDK/builds/226256046#L1845-L1850

Reviewed 12 of 12 files at r1.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on @emawby and @tanaynigam)

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OneSignalSDK/onesignal/src/main/java/com/onesignal/OneSignal.java, line 1694 at r1 (raw file):

         OneSignalStateSynchronizer.updateDeviceInfo(deviceInfo);
      } catch (JSONException exception) {
         String operation = language.equals("") ? "remove" : "set";

We can omit this operation logic as you can only set a language, not remove it.

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OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageContext.java, line 19 at r1 (raw file):

    public LanguageContext(OSSharedPreferences preferences) {
        instance = this;
        if ( preferences.getString(

nit, remove extra space before preferences.

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OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageProviderAppDefined.java, line 4 at r1 (raw file):

import com.onesignal.OSSharedPreferences;

public class LanguageProviderAppDefined implements LanguageProvider{

nit, should be space after LanguageProvider

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OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageProviderDevice.java, line 5 at r1 (raw file):

import java.util.Locale;

public class LanguageProviderDevice implements LanguageProvider{

nit, should be space after LanguageProvider

[jkasten2]

Reviewed 5 of 5 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @emawby)

[Jeasmine]

Reviewable status: all files reviewed, 4 unresolved discussions (waiting on @tanaynigam)

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OneSignalSDK/onesignal/src/main/java/com/onesignal/OneSignal.java, line 1677 at r2 (raw file):

      }

      if (shouldLogUserPrivacyConsentErrorMessageForMethodName("setLanguage()"))

Instead of "setLanguage()" string, what about using the constant OSTaskRemoteController.SET_Language?

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OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageContext.java, line 19 at r2 (raw file):

    public LanguageContext(OSSharedPreferences preferences) {
        instance = this;
        if (preferences.getString(

For easier readability, would you mind putting the if condition inside a variable?

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OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageProviderAppDefined.java, line 21 at r2 (raw file):

    public String getLanguage() {
        return preferences.getString(
                preferences.getPreferencesName(), PREFS_OS_LANGUAGE, "en");

Code styling comment, would you mind moving the "en" string to a class constant string?

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OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageProviderDevice.java, line 10 at r2 (raw file):

        // https://github.com/OneSignal/OneSignal-Android-SDK/issues/64
        if (lang.equals("iw"))

would it make sense to have enums instead of strings?

[jkasten2]

Reviewed 7 of 7 files at r3.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on @tanaynigam)