Add theme setting

This prepares that different themes can be added. Currently light and
dark will just use the default OK theme.

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/Constants.java

@@ -103,6 +103,7 @@ public final class Constants {
         public static final String PROXY_HOST = "proxyHost";
         public static final String PROXY_PORT = "proxyPort";
         public static final String PROXY_TYPE = "proxyType";
+        public static final String THEME = "theme";
     }
 
     /**

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

@@ -53,6 +53,7 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
     public static final String ACTION_PREFS_CLOUD = "org.sufficientlysecure.keychain.ui.PREFS_CLOUD";
     public static final String ACTION_PREFS_ADV = "org.sufficientlysecure.keychain.ui.PREFS_ADV";
     public static final String ACTION_PREFS_PROXY = "org.sufficientlysecure.keychain.ui.PREFS_PROXY";
+    public static final String ACTION_PREFS_GUI = "org.sufficientlysecure.keychain.ui.PREFS_GUI";
 
     public static final int REQUEST_CODE_KEYSERVER_PREF = 0x00007005;
 
@@ -106,6 +107,10 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
             initializeUseNumKeypadForYubiKeyPin(
                     (CheckBoxPreference) findPreference(Constants.Pref.USE_NUMKEYPAD_FOR_YUBIKEY_PIN));
 
+        } else if (action != null && action.equals(ACTION_PREFS_GUI)) {
+            addPreferencesFromResource(R.xml.gui_preferences);
+
+            initializeTheme((ListPreference) findPreference(Constants.Pref.THEME));
         }
     }
 
@@ -425,14 +430,30 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
                 mUseTor.setEnabled(true);
             }
         }
-
     }
 
-    @TargetApi(Build.VERSION_CODES.KITKAT)
+    /**
+     * This fragment shows gui preferences.
+     */
+    public static class GuiPrefsFragment extends PreferenceFragment {
+
+        @Override
+        public void onCreate(Bundle savedInstanceState) {
+            super.onCreate(savedInstanceState);
+
+
+            // Load the preferences from an XML resource
+            addPreferencesFromResource(R.xml.gui_preferences);
+
+            initializeTheme((ListPreference) findPreference(Constants.Pref.THEME));
+        }
+    }
+
     protected boolean isValidFragment(String fragmentName) {
         return AdvancedPrefsFragment.class.getName().equals(fragmentName)
                 || CloudSearchPrefsFragment.class.getName().equals(fragmentName)
                 || ProxyPrefsFragment.class.getName().equals(fragmentName)
+                || GuiPrefsFragment.class.getName().equals(fragmentName)
                 || super.isValidFragment(fragmentName);
     }
 
@@ -461,6 +482,19 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
                 });
     }
 
+    private static void initializeTheme(final ListPreference mTheme) {
+        mTheme.setValue(sPreferences.getTheme());
+        mTheme.setSummary(mTheme.getEntry());
+        mTheme.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
+            public boolean onPreferenceChange(Preference preference, Object newValue) {
+                mTheme.setValue((String) newValue);
+                mTheme.setSummary(mTheme.getEntry());
+                sPreferences.setTheme((String) newValue);
+                return false;
+            }
+        });
+    }
+
     private static void initializeSearchKeyserver(final CheckBoxPreference mSearchKeyserver) {
         Preferences.CloudSearchPrefs prefs = sPreferences.getCloudSearchPrefs();
         mSearchKeyserver.setChecked(prefs.searchKeyserver);

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

@@ -22,6 +22,7 @@ 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;
@@ -29,6 +30,7 @@ import android.view.ViewGroup;
 import android.widget.TextView;
 
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.util.Preferences;
 
 /**
  * Setups Toolbar
@@ -36,9 +38,19 @@ import org.sufficientlysecure.keychain.R;
 public abstract class BaseActivity extends AppCompatActivity {
     protected Toolbar mToolbar;
     protected View mStatusBar;
+    private static Preferences sPreferences;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        sPreferences = Preferences.getPreferences(this);
+        int themeId = R.style.LightTheme;
+        if ("dark".equals(sPreferences.getTheme())) {
+            themeId = R.style.DarkTheme;
+        }
+
+        ContextThemeWrapper w = new ContextThemeWrapper(this, themeId);
+        getTheme().setTo(w.getTheme());
+
         super.onCreate(savedInstanceState);
         initLayout();
         initToolbar();

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Preferences.java

@@ -220,6 +220,15 @@ public class Preferences {
         return mSharedPreferences.getBoolean(Pref.TEXT_USE_COMPRESSION, true);
     }
 
+    public String getTheme() {
+        return mSharedPreferences.getString(Pref.THEME, "light");
+    }
+
+    public void setTheme(String value) {
+        SharedPreferences.Editor editor = mSharedPreferences.edit();
+        editor.putString(Constants.Pref.THEME, value);
+        editor.commit();
+    }
 
     public void setUseArmor(boolean useArmor) {
         SharedPreferences.Editor editor = mSharedPreferences.edit();