Add dark mode

app/src/main/java/com/github/gotify/settings/SettingsActivity.java

@@ -0,0 +1,56 @@
+package com.github.gotify.settings;
+
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.view.MenuItem;
+import androidx.annotation.NonNull;
+import androidx.appcompat.app.ActionBar;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.preference.PreferenceFragmentCompat;
+import androidx.preference.PreferenceManager;
+import com.github.gotify.R;
+
+public class SettingsActivity extends AppCompatActivity
+        implements SharedPreferences.OnSharedPreferenceChangeListener {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.settings_activity);
+        getSupportFragmentManager()
+                .beginTransaction()
+                .replace(R.id.settings, new SettingsFragment())
+                .commit();
+        setSupportActionBar(findViewById(R.id.toolbar));
+        ActionBar actionBar = getSupportActionBar();
+        if (actionBar != null) {
+            actionBar.setDisplayHomeAsUpEnabled(true);
+            actionBar.setDisplayShowCustomEnabled(true);
+        }
+        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
+        sharedPreferences.registerOnSharedPreferenceChangeListener(this);
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
+        if (item.getItemId() == android.R.id.home) {
+            finish();
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
+    @Override
+    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
+        if (getString(R.string.setting_key_theme).equals(key)) {
+            ThemeHelper.setTheme(
+                    this, sharedPreferences.getString(key, getString(R.string.theme_default)));
+        }
+    }
+
+    public static class SettingsFragment extends PreferenceFragmentCompat {
+        @Override
+        public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+            setPreferencesFromResource(R.xml.root_preferences, rootKey);
+        }
+    }
+}