Add setting to configure the splitview mode

res/values/arrays.xml

@@ -713,4 +713,15 @@
         <item name="3">ALWAYS</item>
     </string-array>
 
+    <string-array name="global_settings_splitview_mode_entries">
+        <item>@string/global_settings_splitview_always</item>
+        <item>@string/global_settings_splitview_never</item>
+        <item>@string/global_settings_splitview_when_in_landscape</item>
+    </string-array>
+
+    <string-array name="global_settings_splitview_mode_values">
+        <item>ALWAYS</item>
+        <item>NEVER</item>
+        <item>WHEN_IN_LANDSCAPE</item>
+    </string-array>
 </resources>

res/values/strings.xml

@@ -1129,4 +1129,9 @@ Please submit bug reports, contribute new features and ask questions at
     <string name="upgrade_database_format">Upgrading database of account \"<xliff:g id="account">%s</xliff:g>\"</string>
 
     <string name="message_list_loading">Loading…</string>
+
+    <string name="global_settings_splitview_mode_label">Show split-screen</string>
+    <string name="global_settings_splitview_always">Always</string>
+    <string name="global_settings_splitview_never">Never</string>
+    <string name="global_settings_splitview_when_in_landscape">When in Landscape orientation</string>
 </resources>

res/xml/global_preferences.xml

@@ -156,6 +156,14 @@
                 android:title="@string/global_settings_threaded_view_label"
                 android:summary="@string/global_settings_threaded_view_summary" />
 
+            <ListPreference
+                android:persistent="false"
+                android:key="splitview_mode"
+                android:title="@string/global_settings_splitview_mode_label"
+                android:entries="@array/global_settings_splitview_mode_entries"
+                android:entryValues="@array/global_settings_splitview_mode_values"
+                android:dialogTitle="@string/global_settings_splitview_mode_label" />
+
         </PreferenceCategory>
 
         <PreferenceCategory

src/com/fsck/k9/K9.java

@@ -210,6 +210,15 @@ public class K9 extends Application {
         NEVER
     }
 
+    /**
+     * Controls when to use the message list split view.
+     */
+    public enum SplitViewMode {
+        ALWAYS,
+        NEVER,
+        WHEN_IN_LANDSCAPE
+    }
+
     private static boolean mMessageListCheckboxes = false;
     private static int mMessageListPreviewLines = 2;
 
@@ -251,6 +260,7 @@ public class K9 extends Application {
 
     private static boolean sUseBackgroundAsUnreadIndicator = true;
     private static boolean sThreadedViewEnabled = true;
+    private static SplitViewMode sSplitViewMode = SplitViewMode.WHEN_IN_LANDSCAPE;
 
     /**
      * @see #areDatabasesUpToDate()
@@ -530,6 +540,7 @@ public class K9 extends Application {
         editor.putString("attachmentdefaultpath", mAttachmentDefaultPath);
         editor.putBoolean("useBackgroundAsUnreadIndicator", sUseBackgroundAsUnreadIndicator);
         editor.putBoolean("threadedView", sThreadedViewEnabled);
+        editor.putString("splitViewMode", sSplitViewMode.name());
         fontSizes.save(editor);
     }
 
@@ -737,6 +748,11 @@ public class K9 extends Application {
             sNotificationQuickDelete = NotificationQuickDelete.valueOf(notificationQuickDelete);
         }
 
+        String splitViewMode = sprefs.getString("splitViewMode", null);
+        if (splitViewMode != null) {
+            sSplitViewMode = SplitViewMode.valueOf(splitViewMode);
+        }
+
         mAttachmentDefaultPath = sprefs.getString("attachmentdefaultpath",  Environment.getExternalStorageDirectory().toString());
         sUseBackgroundAsUnreadIndicator = sprefs.getBoolean("useBackgroundAsUnreadIndicator", true);
         sThreadedViewEnabled = sprefs.getBoolean("threadedView", true);
@@ -1218,10 +1234,10 @@ public class K9 extends Application {
     }
 
     public static boolean wrapFolderNames() {
-    	return mWrapFolderNames;
+        return mWrapFolderNames;
     }
     public static void setWrapFolderNames(final boolean state) {
-    	mWrapFolderNames = state;
+        mWrapFolderNames = state;
     }
 
     public static String getAttachmentDefaultPath() {
@@ -1267,6 +1283,14 @@ public class K9 extends Application {
         sThreadedViewEnabled = enable;
     }
 
+    public static synchronized SplitViewMode getSplitViewMode() {
+        return sSplitViewMode;
+    }
+
+    public static synchronized void setSplitViewMode(SplitViewMode mode) {
+        sSplitViewMode = mode;
+    }
+
     /**
      * Check if we already know whether all databases are using the current database schema.
      *

src/com/fsck/k9/activity/MessageList.java

@@ -3,6 +3,7 @@ package com.fsck.k9.activity;
 import android.app.SearchManager;
 import android.content.Context;
 import android.content.Intent;
+import android.content.res.Configuration;
 import android.os.Build;
 import android.os.Bundle;
 import android.support.v4.app.FragmentManager;
@@ -66,6 +67,8 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     public static final String EXTRA_SEARCH_ACCOUNT = "com.fsck.k9.search_account";
     private static final String EXTRA_SEARCH_FOLDER = "com.fsck.k9.search_folder";
 
+    private static final String STATE_DISPLAY_MODE = "displayMode";
+
     public static void actionDisplaySearch(Context context, SearchSpecification search,
             boolean noThreading, boolean newTask) {
         actionDisplaySearch(context, search, noThreading, newTask, true);
@@ -103,6 +106,12 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
         return intent;
     }
 
+    private enum DisplayMode {
+        MESSAGE_LIST,
+        MESSAGE_VIEW,
+        SPLIT_VIEW
+    }
+
 
     private StorageManager.StorageListener mStorageListener = new StorageListenerImplementation();
 
@@ -112,6 +121,7 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     private TextView mActionBarUnread;
     private Menu mMenu;
 
+    private ViewGroup mMessageListContainer;
     private ViewGroup mMessageViewContainer;
     private View mMessageViewPlaceHolder;
 
@@ -134,6 +144,9 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
      */
     private boolean mNoThreading;
 
+    private DisplayMode mDisplayMode;
+
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -152,6 +165,7 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
 
         decodeExtras(getIntent());
         initializeFragments();
+        initializeDisplayMode(savedInstanceState);
         initializeLayout();
 
         ChangeLog cl = new ChangeLog(this);
@@ -176,12 +190,56 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
         }
     }
 
+    private void initializeDisplayMode(Bundle savedInstanceState) {
+        if (savedInstanceState != null) {
+            mDisplayMode = (DisplayMode) savedInstanceState.getSerializable(STATE_DISPLAY_MODE);
+        } else {
+            mDisplayMode = DisplayMode.MESSAGE_LIST;
+        }
+
+        switch (K9.getSplitViewMode()) {
+            case ALWAYS: {
+                mDisplayMode = DisplayMode.SPLIT_VIEW;
+                break;
+            }
+            case NEVER: {
+                // Either use the restored setting or DisplayMode.MESSAGE_LIST set above
+                break;
+            }
+            case WHEN_IN_LANDSCAPE: {
+                int orientation = getResources().getConfiguration().orientation;
+                if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
+                    mDisplayMode = DisplayMode.SPLIT_VIEW;
+                } else if (mMessageViewFragment != null) {
+                    mDisplayMode = DisplayMode.MESSAGE_VIEW;
+                } else {
+                    mDisplayMode = DisplayMode.MESSAGE_LIST;
+                }
+                break;
+            }
+        }
+    }
+
     private void initializeLayout() {
+        mMessageListContainer = (ViewGroup) findViewById(R.id.message_list_container);
         mMessageViewContainer = (ViewGroup) findViewById(R.id.message_view_container);
         mMessageViewPlaceHolder = getLayoutInflater().inflate(R.layout.empty_message_view, null);
 
-        if (mMessageViewFragment == null) {
+        switch (mDisplayMode) {
-            showMessageViewPlaceHolder();
+            case MESSAGE_LIST: {
+                showMessageList();
+                break;
+            }
+            case MESSAGE_VIEW: {
+                showMessageView();
+                break;
+            }
+            case SPLIT_VIEW: {
+                if (mMessageViewFragment == null) {
+                    showMessageViewPlaceHolder();
+                }
+                break;
+            }
         }
     }
 
@@ -272,6 +330,13 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
         StorageManager.getInstance(getApplication()).addListener(mStorageListener);
     }
 
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+
+        outState.putSerializable(STATE_DISPLAY_MODE, mDisplayMode);
+    }
+
     private void initializeActionBar() {
         mActionBar = getSupportActionBar();
 
@@ -628,7 +693,11 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
             mMessageViewFragment = fragment;
             ft.commit();
 
-            mMessageListFragment.setActiveMessage(messageReference);
+            if (mDisplayMode == DisplayMode.SPLIT_VIEW) {
+                mMessageListFragment.setActiveMessage(messageReference);
+            } else {
+                showMessageView();
+            }
         }
     }
 
@@ -673,8 +742,12 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
         FragmentManager fragmentManager = getSupportFragmentManager();
         mMessageListFragment = (MessageListFragment) fragmentManager.findFragmentById(
                 R.id.message_list_container);
+        mMessageViewFragment = (MessageViewFragment) fragmentManager.findFragmentById(
+                R.id.message_view_container);
 
-        showMessageViewPlaceHolder();
+        if (mDisplayMode == DisplayMode.SPLIT_VIEW) {
+            showMessageViewPlaceHolder();
+        }
 
         configureMenu(mMenu);
     }
@@ -753,13 +826,7 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     }
 
     private void showMessageViewPlaceHolder() {
-        // Remove MessageViewFragment if necessary
+        removeMessageViewFragment();
-        if (mMessageViewFragment != null) {
-            FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
-            ft.remove(mMessageViewFragment);
-            mMessageViewFragment = null;
-            ft.commit();
-        }
 
         // Add placeholder view if necessary
         if (mMessageViewPlaceHolder.getParent() == null) {
@@ -769,6 +836,18 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
         mMessageListFragment.setActiveMessage(null);
     }
 
+    /**
+     * Remove MessageViewFragment if necessary.
+     */
+    private void removeMessageViewFragment() {
+        if (mMessageViewFragment != null) {
+            FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
+            ft.remove(mMessageViewFragment);
+            mMessageViewFragment = null;
+            ft.commit();
+        }
+    }
+
     @Override
     public void remoteSearchStarted() {
         // Remove action button for remote search
@@ -778,9 +857,10 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     @Override
     public void goBack() {
         FragmentManager fragmentManager = getSupportFragmentManager();
-        if (fragmentManager.getBackStackEntryCount() > 0) {
+        if (mDisplayMode == DisplayMode.MESSAGE_VIEW) {
+            showMessageList();
+        } else if (fragmentManager.getBackStackEntryCount() > 0) {
             fragmentManager.popBackStack();
-            showMessageViewPlaceHolder();
         } else if (mMessageListFragment.isManualSearch()) {
             onBackPressed();
         } else if (!mSingleFolderMode) {
@@ -871,4 +951,20 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     private void showNextMessage() {
         //TODO: implement
     }
+
+    private void showMessageList() {
+        mDisplayMode = DisplayMode.MESSAGE_LIST;
+
+        mMessageViewContainer.setVisibility(View.GONE);
+        mMessageListContainer.setVisibility(View.VISIBLE);
+        removeMessageViewFragment();
+        mMessageListFragment.setActiveMessage(null);
+    }
+
+    private void showMessageView() {
+        mDisplayMode = DisplayMode.MESSAGE_VIEW;
+
+        mMessageListContainer.setVisibility(View.GONE);
+        mMessageViewContainer.setVisibility(View.VISIBLE);
+    }
 }

src/com/fsck/k9/activity/setup/Prefs.java

@@ -24,6 +24,7 @@ import com.fsck.k9.Account;
 import com.fsck.k9.K9;
 import com.fsck.k9.K9.NotificationHideSubject;
 import com.fsck.k9.K9.NotificationQuickDelete;
+import com.fsck.k9.K9.SplitViewMode;
 import com.fsck.k9.Preferences;
 import com.fsck.k9.R;
 import com.fsck.k9.activity.ColorPickerDialog;
@@ -93,6 +94,7 @@ public class Prefs extends K9PreferenceActivity {
     private static final String PREFERENCE_BACKGROUND_AS_UNREAD_INDICATOR = "messagelist_background_as_unread_indicator";
     private static final String PREFERENCE_THREADED_VIEW = "threaded_view";
     private static final String PREFERENCE_FOLDERLIST_WRAP_NAME = "folderlist_wrap_folder_name";
+    private static final String PREFERENCE_SPLITVIEW_MODE = "splitview_mode";
 
     private static final int ACTIVITY_CHOOSE_FOLDER = 1;
 
@@ -139,6 +141,7 @@ public class Prefs extends K9PreferenceActivity {
     private CheckBoxPreference mBatchButtonsUnselect;
     private CheckBoxPreference mBackgroundAsUnreadIndicator;
     private CheckBoxPreference mThreadedView;
+    private ListPreference mSplitViewMode;
 
 
     public static void actionPrefs(Context context) {
@@ -425,6 +428,10 @@ public class Prefs extends K9PreferenceActivity {
             mBatchButtonsArchive.setEnabled(false);
             mBatchButtonsArchive.setSummary(R.string.global_settings_archive_disabled_reason);
         }
+
+        mSplitViewMode = (ListPreference) findPreference(PREFERENCE_SPLITVIEW_MODE);
+        initListPreference(mSplitViewMode, K9.getSplitViewMode().name(),
+                mSplitViewMode.getEntries(), mSplitViewMode.getEntryValues());
     }
 
     private void saveSettings() {
@@ -487,6 +494,7 @@ public class Prefs extends K9PreferenceActivity {
         K9.setBatchButtonsFlag(mBatchButtonsFlag.isChecked());
         K9.setBatchButtonsUnselect(mBatchButtonsUnselect.isChecked());
 
+        K9.setSplitViewMode(SplitViewMode.valueOf(mSplitViewMode.getValue()));
         K9.setAttachmentDefaultPath(mAttachmentPathPreference.getSummary().toString());
         boolean needsRefresh = K9.setBackgroundOps(mBackgroundOps.getValue());
         K9.setUseGalleryBugWorkaround(mUseGalleryBugWorkaround.isChecked());

src/com/fsck/k9/preferences/GlobalSettings.java

@@ -18,6 +18,7 @@ import com.fsck.k9.Account;
 import com.fsck.k9.FontSizes;
 import com.fsck.k9.K9;
 import com.fsck.k9.K9.NotificationHideSubject;
+import com.fsck.k9.K9.SplitViewMode;
 import com.fsck.k9.R;
 import com.fsck.k9.Account.SortType;
 import com.fsck.k9.helper.DateFormatter;
@@ -228,6 +229,9 @@ public class GlobalSettings {
         s.put("threadedView", Settings.versions(
                 new V(20, new BooleanSetting(true))
             ));
+        s.put("splitViewMode", Settings.versions(
+                new V(23, new EnumSetting(SplitViewMode.class, SplitViewMode.WHEN_IN_LANDSCAPE))
+            ));
 
         SETTINGS = Collections.unmodifiableMap(s);
 

src/com/fsck/k9/preferences/Settings.java

@@ -35,7 +35,7 @@ public class Settings {
      *
      * @see SettingsExporter
      */
-    public static final int VERSION = 22;
+    public static final int VERSION = 23;
 
     public static Map<String, Object> validate(int version, Map<String,
             TreeMap<Integer, SettingsDescription>> settings,