Refactor theme changing to avoid code repetition

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/SettingsActivity.java

@@ -33,7 +33,6 @@ import android.preference.PreferenceFragment;
 import android.preference.PreferenceScreen;
 import android.support.v7.widget.Toolbar;
 import android.text.TextUtils;
-import android.view.ContextThemeWrapper;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.LinearLayout;
@@ -42,6 +41,7 @@ import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.compatibility.AppCompatPreferenceActivity;
 import org.sufficientlysecure.keychain.ui.util.Notify;
+import org.sufficientlysecure.keychain.ui.util.ThemeChanger;
 import org.sufficientlysecure.keychain.ui.widget.IntegerListPreference;
 import org.sufficientlysecure.keychain.util.Log;
 import org.sufficientlysecure.keychain.util.Preferences;
@@ -60,13 +60,14 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
 
     private PreferenceScreen mKeyServerPreference = null;
     private static Preferences sPreferences;
-    private String mCurrentTheme = null;
+    private ThemeChanger mThemeChanger;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         sPreferences = Preferences.getPreferences(this);
 
-        changeTheme();
+        mThemeChanger = new ThemeChanger(this);
+        mThemeChanger.changeTheme();
         super.onCreate(savedInstanceState);
 
         setupToolbar();
@@ -122,31 +123,13 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
     protected void onResume() {
         super.onResume();
 
-        if (changeTheme()) {
+        if (mThemeChanger.changeTheme()) {
             Intent intent = getIntent();
             finish();
             startActivity(intent);
         }
     }
 
-    protected boolean changeTheme() {
-        String newTheme = sPreferences.getTheme();
-        if (mCurrentTheme != null && mCurrentTheme.equals(newTheme)) {
-            return false;
-        }
-
-        int themeId = R.style.LightTheme;
-        if (Constants.Pref.Theme.DARK.equals(newTheme)) {
-            themeId = R.style.DarkTheme;
-        }
-
-        ContextThemeWrapper w = new ContextThemeWrapper(this, themeId);
-        getTheme().setTo(w.getTheme());
-        mCurrentTheme = newTheme;
-
-        return true;
-    }
-
     /**
      * Hack to get Toolbar in PreferenceActivity. See http://stackoverflow.com/a/26614696
      */

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/BaseActivity.java

@@ -23,16 +23,14 @@ import android.os.Bundle;
 import android.support.v7.app.ActionBar;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
-import android.view.ContextThemeWrapper;
 import android.view.Gravity;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
 
-import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
-import org.sufficientlysecure.keychain.util.Preferences;
+import org.sufficientlysecure.keychain.ui.util.ThemeChanger;
 
 /**
  * Setups Toolbar
@@ -40,14 +38,12 @@ import org.sufficientlysecure.keychain.util.Preferences;
 public abstract class BaseActivity extends AppCompatActivity {
     protected Toolbar mToolbar;
     protected View mStatusBar;
-    private static Preferences sPreferences;
-    private String mCurrentTheme = null;
+    protected ThemeChanger mThemeChanger;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
-        sPreferences = Preferences.getPreferences(this);
-
-        changeTheme();
+        mThemeChanger = new ThemeChanger(this);
+        mThemeChanger.changeTheme();
         super.onCreate(savedInstanceState);
         initLayout();
         initToolbar();
@@ -57,37 +53,13 @@ public abstract class BaseActivity extends AppCompatActivity {
     protected void onResume() {
         super.onResume();
 
-        if (changeTheme()) {
+        if (mThemeChanger.changeTheme()) {
             Intent intent = getIntent();
             finish();
             startActivity(intent);
         }
     }
 
-    /**
-     * Apply the theme set in preferences if it isn't equal to mCurrentTheme
-     * anymore or mCurrentTheme hasn't been set yet.
-     * If a new theme is applied in this method, then return true, so
-     * the caller can re-create the activity, if need be.
-     */
-    protected boolean changeTheme() {
-        String newTheme = sPreferences.getTheme();
-        if (mCurrentTheme != null && mCurrentTheme.equals(newTheme)) {
-            return false;
-        }
-
-        int themeId = R.style.LightTheme;
-        if (Constants.Pref.Theme.DARK.equals(newTheme)) {
-            themeId = R.style.DarkTheme;
-        }
-
-        ContextThemeWrapper w = new ContextThemeWrapper(this, themeId);
-        getTheme().setTo(w.getTheme());
-        mCurrentTheme = newTheme;
-
-        return true;
-    }
-
     protected void initLayout() {
 
     }

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/util/ThemeChanger.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2015 Thialfihar <thi@thialfihar.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.ui.util;
+
+import android.content.Context;
+import android.view.ContextThemeWrapper;
+
+import org.sufficientlysecure.keychain.Constants;
+import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.util.Preferences;
+
+public class ThemeChanger {
+    private Context mContext;
+    private Preferences mPreferences;
+    private String mCurrentTheme = null;
+
+    public ThemeChanger(Context context) {
+        mContext = context;
+        mPreferences = Preferences.getPreferences(mContext);
+    }
+
+    /**
+     * Apply the theme set in preferences if it isn't equal to mCurrentTheme
+     * anymore or mCurrentTheme hasn't been set yet.
+     * If a new theme is applied in this method, then return true, so
+     * the caller can re-create the activity, if need be.
+     */
+    public boolean changeTheme() {
+        String newTheme = mPreferences.getTheme();
+        if (mCurrentTheme != null && mCurrentTheme.equals(newTheme)) {
+            return false;
+        }
+
+        int themeId = R.style.LightTheme;
+        if (Constants.Pref.Theme.DARK.equals(newTheme)) {
+            themeId = R.style.DarkTheme;
+        }
+
+        ContextThemeWrapper w = new ContextThemeWrapper(mContext, themeId);
+        mContext.getTheme().setTo(w.getTheme());
+        mCurrentTheme = newTheme;
+
+        return true;
+    }
+}