Add theme selector to first screen

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/welcome/WelcomeFragmentIntro.java

@@ -16,7 +16,10 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>. */
 package nodomain.freeyourgadget.gadgetbridge.activities.welcome;
 
+import android.content.Intent;
+import android.content.SharedPreferences;
 import android.os.Bundle;
+import android.os.Handler;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -24,11 +27,18 @@ import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.localbroadcastmanager.content.LocalBroadcastManager;
+
+import com.google.android.material.textfield.MaterialAutoCompleteTextView;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.Arrays;
+
+import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 import nodomain.freeyourgadget.gadgetbridge.R;
+import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 
 public class WelcomeFragmentIntro extends Fragment {
     private static final Logger LOG = LoggerFactory.getLogger(WelcomeFragmentIntro.class);
@@ -37,6 +47,28 @@ public class WelcomeFragmentIntro extends Fragment {
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
         super.onCreateView(inflater, container, savedInstanceState);
-        return inflater.inflate(R.layout.fragment_welcome_intro, container, false);
+
+        final View view = inflater.inflate(R.layout.fragment_welcome_intro, container, false);
+        final String[] themes = getResources().getStringArray(R.array.pref_theme_values);
+        final Prefs prefs = GBApplication.getPrefs();
+        final String currentTheme = prefs.getString("pref_key_theme", getString(R.string.pref_theme_value_system));
+        final int currentThemeIndex = Arrays.asList(themes).indexOf(currentTheme);
+
+        final MaterialAutoCompleteTextView themeMenu = view.findViewById(R.id.app_theme_dropdown_menu);
+        themeMenu.setSaveEnabled(false);  // https://github.com/material-components/material-components-android/issues/1464#issuecomment-1258051448
+        themeMenu.setText(getResources().getStringArray(R.array.pref_theme_options)[currentThemeIndex], false);
+        themeMenu.setOnItemClickListener((adapterView, view1, i, l) -> {
+            final SharedPreferences.Editor editor = prefs.getPreferences().edit();
+            editor.putString("pref_key_theme", themes[i]).apply();
+            final Handler handler = new Handler();
+            handler.postDelayed(() -> {
+                // Delay recreation of the Activity to give the dropdown some time to settle.
+                // If we recreate it immediately, the theme popup will reopen, which is not what the user expects.
+                Intent intent = new Intent();
+                intent.setAction(GBApplication.ACTION_THEME_CHANGE);
+                LocalBroadcastManager.getInstance(requireContext()).sendBroadcast(intent);
+            }, 500);
+        });
+        return view;
     }
 }

app/src/main/res/layout/fragment_welcome_intro.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
@@ -40,5 +41,21 @@
             android:textAlignment="center"
             android:text="@string/first_start_intro_tag_line" />
 
+        <com.google.android.material.textfield.TextInputLayout
+            style="@style/Widget.Material3.TextInputLayout.OutlinedBox.ExposedDropdownMenu"
+            android:id="@+id/app_theme_dropdown_input"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="30dp"
+            android:hint="@string/pref_title_theme">
+
+            <AutoCompleteTextView
+                android:id="@+id/app_theme_dropdown_menu"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:inputType="none"
+                app:simpleItems="@array/pref_theme_options" />
+
+        </com.google.android.material.textfield.TextInputLayout>
     </LinearLayout>
 </RelativeLayout>