Made dark theme a pro feature

README.md

@@ -26,12 +26,12 @@ Features
 * Two way synchronization
 * Offline storage and operations
 * Material design
-* Dark theme
 
 Pro features
 ------------
 
 * Signatures
+* Dark theme
 * Account colors
 * Standard replies
 * Sort on time, unread or starred

app/src/main/java/eu/faircode/email/ActivityBase.java

@@ -35,7 +35,8 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
     protected void onCreate(Bundle savedInstanceState) {
         Log.i(Helper.TAG, "Create " + this.getClass().getName() + " version=" + BuildConfig.VERSION_NAME);
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
-        String theme = prefs.getString("theme", "light");
+        boolean pro = prefs.getBoolean("pro", false);
+        String theme = (pro ? prefs.getString("theme", "light") : "light");
         setTheme("light".equals(theme) ? R.style.AppThemeLight : R.style.AppThemeDark);
         PreferenceManager.getDefaultSharedPreferences(this).registerOnSharedPreferenceChangeListener(this);
         super.onCreate(savedInstanceState);

app/src/main/java/eu/faircode/email/FragmentSetup.java

@@ -203,10 +203,16 @@ public class FragmentSetup extends FragmentEx {
         tbDarkTheme.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton button, boolean checked) {
-                if (checked != (Boolean) button.getTag()) {
-                    button.setTag(checked);
-                    tbDarkTheme.setChecked(checked);
-                    prefs.edit().putString("theme", checked ? "dark" : "light").apply();
+                if (prefs.getBoolean("pro", false)) {
+                    if (checked != (Boolean) button.getTag()) {
+                        button.setTag(checked);
+                        tbDarkTheme.setChecked(checked);
+                        prefs.edit().putString("theme", checked ? "dark" : "light").apply();
+                    }
+                } else {
+                    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
+                    fragmentTransaction.replace(R.id.content_frame, new FragmentPro()).addToBackStack("pro");
+                    fragmentTransaction.commit();
                 }
             }
         });