Android: Send locale/language change events on system locale changes

This enables applications to retranslate or otherwise update their UI
when the Android system locale/language settings are changed during
their runtime.

Change-Id: Id482ca146080d9f3e74990f64e686f6b3504887c
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
(cherry picked from commit 83483b8b200ab5cedf659f418c7296719902ddc4)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/android/jar/src/org/qtproject/qt/android/QtActivityBase.java

@@ -8,6 +8,7 @@ import android.app.Activity;
 import android.app.AlertDialog;
 import android.app.Dialog;
 import android.content.Intent;
+import android.content.pm.ActivityInfo;
 import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.net.Uri;
@@ -29,6 +30,7 @@ public class QtActivityBase extends Activity
     private String m_applicationParams = "";
     private boolean m_isCustomThemeSet = false;
     private boolean m_retainNonConfigurationInstance = false;
+    private Configuration m_prevConfig;
 
     private QtActivityDelegate m_delegate;
 
@@ -122,6 +124,8 @@ public class QtActivityBase extends Activity
             e.printStackTrace();
             showErrorDialog();
         }
+
+        m_prevConfig = new Configuration(getResources().getConfiguration());
     }
 
     @Override
@@ -183,6 +187,12 @@ public class QtActivityBase extends Activity
     {
         super.onConfigurationChanged(newConfig);
         m_delegate.handleUiModeChange(newConfig.uiMode & Configuration.UI_MODE_NIGHT_MASK);
+
+        int diff = newConfig.diff(m_prevConfig);
+        if ((diff & ActivityInfo.CONFIG_LOCALE) != 0)
+            QtNative.updateLocale();
+
+        m_prevConfig = new Configuration(newConfig);
     }
 
     @Override

src/android/jar/src/org/qtproject/qt/android/QtNative.java

@@ -435,6 +435,7 @@ public class QtNative
 
     // application methods
     static native void updateApplicationState(int state);
+    static native void updateLocale();
 
     // menu methods
     static native boolean onPrepareOptionsMenu(Menu menu);

src/plugins/platforms/android/androidjnimain.cpp

@@ -633,6 +633,12 @@ static void updateApplicationState(JNIEnv */*env*/, jobject /*thiz*/, jint state
     }
 }
 
+static void updateLocale(JNIEnv */*env*/, jobject /*thiz*/)
+{
+    QCoreApplication::postEvent(QCoreApplication::instance(), new QEvent(QEvent::LocaleChange));
+    QCoreApplication::postEvent(QCoreApplication::instance(), new QEvent(QEvent::LanguageChange));
+}
+
 static void handleOrientationChanged(JNIEnv */*env*/, jobject /*thiz*/, jint newRotation, jint nativeOrientation)
 {
     // Array of orientations rotated in 90 degree increments, counterclockwise
@@ -736,7 +742,8 @@ static JNINativeMethod methods[] = {
     { "updateApplicationState", "(I)V", (void *)updateApplicationState },
     { "onActivityResult", "(IILandroid/content/Intent;)V", (void *)onActivityResult },
     { "onNewIntent", "(Landroid/content/Intent;)V", (void *)onNewIntent },
-    { "onBind", "(Landroid/content/Intent;)Landroid/os/IBinder;", (void *)onBind }
+    { "onBind", "(Landroid/content/Intent;)Landroid/os/IBinder;", (void *)onBind },
+    { "updateLocale", "()V", (void *)updateLocale },
 };
 
 #define FIND_AND_CHECK_CLASS(CLASS_NAME) \