Set theme result from onBackPressed

app/src/main/java/com/philliphsu/clock2/settings/SettingsActivity.java

@@ -1,6 +1,11 @@
 package com.philliphsu.clock2.settings;
 
+import android.app.Activity;
+import android.content.Intent;
+import android.content.SharedPreferences;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
+import android.view.MenuItem;
 
 import com.philliphsu.clock2.BaseActivity;
 import com.philliphsu.clock2.R;
@@ -11,9 +16,14 @@ import com.philliphsu.clock2.R;
 public class SettingsActivity extends BaseActivity {
     public static final String EXTRA_THEME_CHANGED = "com.philliphsu.clock2.settings.extra.THEME_CHANGED";
 
+    private String mInitialTheme;
+    private SharedPreferences mPrefs;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        mPrefs = PreferenceManager.getDefaultSharedPreferences(this);
+        mInitialTheme = getSelectedTheme();
     }
 
     @Override
@@ -30,4 +40,31 @@ public class SettingsActivity extends BaseActivity {
     protected boolean isDisplayShowTitleEnabled() {
         return true;
     }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case android.R.id.home:
+                setThemeResult(getSelectedTheme());
+                return false; // Don't capture, proceed as usual
+            default:
+                return false;
+        }
+    }
+
+    @Override
+    public void onBackPressed() {
+        setThemeResult(getSelectedTheme());
+        super.onBackPressed();
+    }
+
+    private String getSelectedTheme() {
+        return mPrefs.getString(getString(R.string.key_theme), "");
+    }
+
+    private void setThemeResult(String selectedTheme) {
+        Intent result = new Intent();
+        result.putExtra(EXTRA_THEME_CHANGED, !selectedTheme.equals(mInitialTheme));
+        setResult(Activity.RESULT_OK, result);
+    }
 }

app/src/main/java/com/philliphsu/clock2/settings/SettingsFragment.java

@@ -1,8 +1,6 @@
 package com.philliphsu.clock2.settings;
 
-import android.app.Activity;
 import android.content.Context;
-import android.content.Intent;
 import android.content.SharedPreferences;
 import android.media.AudioManager;
 import android.media.Ringtone;
@@ -11,25 +9,17 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.preference.Preference;
 import android.preference.PreferenceFragment;
-import android.preference.PreferenceManager;
 import android.preference.RingtonePreference;
-import android.view.MenuItem;
 
 import com.philliphsu.clock2.R;
 
 public class SettingsFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {
 
-    private String mInitialTheme;
-    private SharedPreferences mPrefs;
-
     public SettingsFragment() {}
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        // We don't have a menu, but this is needed so we can receive callbacks to the options menu.
-        // The only callback we are interested in is onOptionsItemSelected().
-        setHasOptionsMenu(true);
         addPreferencesFromResource(R.xml.preferences);
         // Set ringtone summary
         setSummary(getPreferenceScreen().getSharedPreferences(), getString(R.string.key_timer_ringtone));
@@ -45,8 +35,6 @@ public class SettingsFragment extends PreferenceFragment implements SharedPrefer
                 return true;
             }
         });
-        mPrefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
-        mInitialTheme = mPrefs.getString(keyOfThemePreference(), "");
     }
 
     @Override
@@ -63,43 +51,9 @@ public class SettingsFragment extends PreferenceFragment implements SharedPrefer
                 .unregisterOnSharedPreferenceChangeListener(this);
     }
 
-    @Override
-    public boolean onOptionsItemSelected(MenuItem item) {
-        /*
-         * https://developer.android.com/guide/topics/ui/menus.html#RespondingOptionsMenu
-         * "If your activity includes fragments, the system first calls onOptionsItemSelected()
-         * for the activity then for each fragment (in the order each fragment was added)
-         * until one returns true or all fragments have been called."
-         */
-        switch (item.getItemId()) {
-            case android.R.id.home:
-                String selectedTheme = mPrefs.getString(keyOfThemePreference(), "");
-                Intent result = new Intent();
-                result.putExtra(SettingsActivity.EXTRA_THEME_CHANGED, !selectedTheme.equals(mInitialTheme));
-                getActivity().setResult(Activity.RESULT_OK, result);
-                return false; // Don't capture, proceed as usual
-            default:
-                return false;
-        }
-    }
-
     @Override
     public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
         setSummary(sharedPreferences, key);
-        // --------------------------------------------------------------------------------------
-        // TOneverDO
-        //
-        // A new instance of the activity would be created and onCreate() called again.
-        // Our reading of the initial theme for the previous instance, which would be destroyed,
-        // would not be retained.
-        // Reading the initial theme *for the new instance* would give us the theme
-        // that the previous instance had just changed to, prior to its recreate().
-        // As such, the result passed back *by the new instance* via the up button
-        // would always indicate the theme didn't change.
-//        if (key.equals(keyOfThemePreference())) {
-//            getActivity().recreate();
-//        }
-        // --------------------------------------------------------------------------------------
     }
 
     private void setSummary(SharedPreferences prefs, String key) {
@@ -112,8 +66,4 @@ public class SettingsFragment extends PreferenceFragment implements SharedPrefer
             pref.setSummary(ringtone.getTitle(getActivity()));
         }
     }
-
-    private String keyOfThemePreference() {
-        return getString(R.string.key_theme);
-    }
 }