Add animation when switching from message list to message view

res/anim/slide_in_left.xml

@@ -0,0 +1,13 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android" >
+
+    <translate
+        android:duration="200"
+        android:fromXDelta="-50%p"
+        android:toXDelta="0" />
+
+    <alpha
+        android:duration="200"
+        android:fromAlpha="0.0"
+        android:toAlpha="1.0" />
+
+</set>

res/anim/slide_in_right.xml

@@ -0,0 +1,13 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android" >
+
+    <translate
+        android:duration="200"
+        android:fromXDelta="50%p"
+        android:toXDelta="0" />
+
+    <alpha
+        android:duration="200"
+        android:fromAlpha="0.0"
+        android:toAlpha="1.0" />
+
+</set>

res/anim/slide_out_left.xml

@@ -0,0 +1,13 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android" >
+
+    <translate
+        android:duration="200"
+        android:fromXDelta="0"
+        android:toXDelta="-50%p" />
+
+    <alpha
+        android:duration="200"
+        android:fromAlpha="1.0"
+        android:toAlpha="0.0" />
+
+</set>

res/anim/slide_out_right.xml

@@ -0,0 +1,13 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android" >
+
+    <translate
+        android:duration="200"
+        android:fromXDelta="0"
+        android:toXDelta="50%p" />
+
+    <alpha
+        android:duration="200"
+        android:fromAlpha="1.0"
+        android:toAlpha="0.0" />
+
+</set>

res/layout/message_list.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.fsck.k9.view.ViewSwitcher xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/container"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent" >
+
+    <FrameLayout
+        android:id="@+id/message_list_container"
+        android:layout_width="fill_parent"
+        android:layout_height="fill_parent" />
+
+    <FrameLayout
+        android:id="@+id/message_view_container"
+        android:layout_width="fill_parent"
+        android:layout_height="fill_parent" />
+
+</com.fsck.k9.view.ViewSwitcher>

res/layout/split_message_list.xml

@@ -18,7 +18,6 @@
         android:layout_width="1px"
         android:layout_height="fill_parent"
         android:background="?attr/messageListDividerColor"
-        android:visibility="gone"
         tools:ignore="PxUsage" />
 
     <FrameLayout

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

@@ -19,6 +19,7 @@ import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.animation.AnimationUtils;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 import android.widget.Toast;
@@ -29,6 +30,7 @@ import com.actionbarsherlock.view.MenuItem;
 import com.fsck.k9.Account;
 import com.fsck.k9.Account.SortType;
 import com.fsck.k9.K9;
+import com.fsck.k9.K9.SplitViewMode;
 import com.fsck.k9.Preferences;
 import com.fsck.k9.R;
 import com.fsck.k9.activity.misc.SwipeGestureDetector.OnSwipeGestureListener;
@@ -50,6 +52,7 @@ import com.fsck.k9.search.SearchSpecification.Searchfield;
 import com.fsck.k9.search.SearchSpecification.SearchCondition;
 import com.fsck.k9.view.MessageHeader;
 import com.fsck.k9.view.MessageTitleView;
+import com.fsck.k9.view.ViewSwitcher;
 
 import de.cketti.library.changelog.ChangeLog;
 
@@ -148,7 +151,6 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     private TextView mActionBarUnread;
     private Menu mMenu;
 
-    private ViewGroup mMessageListContainer;
     private ViewGroup mMessageViewContainer;
     private View mMessageViewPlaceHolder;
 
@@ -180,6 +182,7 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
      * finish the activity.
      */
     private boolean mMessageListWasDisplayed = false;
+    private ViewSwitcher mViewSwitcher;
 
 
     @Override
@@ -191,7 +194,17 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
             return;
         }
 
+        if (useSplitView()) {
             setContentView(R.layout.split_message_list);
+        } else {
+            setContentView(R.layout.message_list);
+            mViewSwitcher = (ViewSwitcher) findViewById(R.id.container);
+            mViewSwitcher.setAnimateFirstView(false);
+            mViewSwitcher.setFirstInAnimation(AnimationUtils.loadAnimation(this, R.anim.slide_in_left));
+            mViewSwitcher.setFirstOutAnimation(AnimationUtils.loadAnimation(this, R.anim.slide_out_right));
+            mViewSwitcher.setSecondInAnimation(AnimationUtils.loadAnimation(this, R.anim.slide_in_right));
+            mViewSwitcher.setSecondOutAnimation(AnimationUtils.loadAnimation(this, R.anim.slide_out_left));
+        }
 
         initializeActionBar();
 
@@ -284,32 +297,23 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
             mDisplayMode = (displayMessage) ? DisplayMode.MESSAGE_VIEW : DisplayMode.MESSAGE_LIST;
         }
 
-        switch (K9.getSplitViewMode()) {
+        if (useSplitView()) {
-            case ALWAYS: {
             mDisplayMode = DisplayMode.SPLIT_VIEW;
-                break;
+        } else if (mMessageViewFragment != null || mDisplayMode == DisplayMode.MESSAGE_VIEW) {
-            }
-            case NEVER: {
-                // Use the value set at the beginning of this method.
-                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) {
             mDisplayMode = DisplayMode.MESSAGE_VIEW;
-                } else {
-                    mDisplayMode = DisplayMode.MESSAGE_LIST;
-                }
-                break;
-            }
         }
     }
 
+    private boolean useSplitView() {
+        SplitViewMode splitViewMode = K9.getSplitViewMode();
+        int orientation = getResources().getConfiguration().orientation;
+
+        return (splitViewMode == SplitViewMode.ALWAYS ||
+                (splitViewMode == SplitViewMode.WHEN_IN_LANDSCAPE &&
+                orientation == Configuration.ORIENTATION_LANDSCAPE));
+    }
+
     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);
     }
@@ -326,7 +330,6 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
             }
             case SPLIT_VIEW: {
                 mMessageListWasDisplayed = true;
-                findViewById(R.id.message_list_divider).setVisibility(View.VISIBLE);
                 if (mMessageViewFragment == null) {
                     showMessageViewPlaceHolder();
                 } else {
@@ -1319,8 +1322,8 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
         mMessageListWasDisplayed = true;
         mDisplayMode = DisplayMode.MESSAGE_LIST;
 
-        mMessageViewContainer.setVisibility(View.GONE);
+        mViewSwitcher.showFirstView();
-        mMessageListContainer.setVisibility(View.VISIBLE);
+
         removeMessageViewFragment();
         mMessageListFragment.setActiveMessage(null);
 
@@ -1330,8 +1333,7 @@ public class MessageList extends K9FragmentActivity implements MessageListFragme
     private void showMessageView() {
         mDisplayMode = DisplayMode.MESSAGE_VIEW;
 
-        mMessageListContainer.setVisibility(View.GONE);
+        mViewSwitcher.showSecondView();
-        mMessageViewContainer.setVisibility(View.VISIBLE);
 
         showMessageTitleView();
     }

src/com/fsck/k9/view/ViewSwitcher.java

@@ -0,0 +1,78 @@
+package com.fsck.k9.view;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.animation.Animation;
+import android.widget.ViewAnimator;
+
+/**
+ * A {@link ViewAnimator} that animates between two child views using different animations
+ * depending on which view is displayed.
+ */
+public class ViewSwitcher extends ViewAnimator {
+    private Animation mFirstInAnimation;
+    private Animation mFirstOutAnimation;
+    private Animation mSecondInAnimation;
+    private Animation mSecondOutAnimation;
+
+
+    public ViewSwitcher(Context context) {
+        super(context);
+    }
+
+    public ViewSwitcher(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public void showFirstView() {
+        if (getDisplayedChild() == 0) {
+            return;
+        }
+
+        setInAnimation(mFirstInAnimation);
+        setOutAnimation(mFirstOutAnimation);
+        setDisplayedChild(0);
+    }
+
+    public void showSecondView() {
+        if (getDisplayedChild() == 1) {
+            return;
+        }
+
+        setInAnimation(mSecondInAnimation);
+        setOutAnimation(mSecondOutAnimation);
+        setDisplayedChild(1);
+    }
+
+    public Animation getFirstInAnimation() {
+        return mFirstInAnimation;
+    }
+
+    public void setFirstInAnimation(Animation inAnimation) {
+        this.mFirstInAnimation = inAnimation;
+    }
+
+    public Animation getmFirstOutAnimation() {
+        return mFirstOutAnimation;
+    }
+
+    public void setFirstOutAnimation(Animation outAnimation) {
+        mFirstOutAnimation = outAnimation;
+    }
+
+    public Animation getSecondInAnimation() {
+        return mSecondInAnimation;
+    }
+
+    public void setSecondInAnimation(Animation inAnimation) {
+        mSecondInAnimation = inAnimation;
+    }
+
+    public Animation getSecondOutAnimation() {
+        return mSecondOutAnimation;
+    }
+
+    public void setSecondOutAnimation(Animation outAnimation) {
+        mSecondOutAnimation = outAnimation;
+    }
+}