MainActivity: Add animation when switching fragments.

app/src/main/java/org/yaaic/activity/MainActivity.java

@@ -169,9 +169,13 @@ public class MainActivity extends ActionBarActivity implements YaaicActivity, Se
     private void switchToFragment(Fragment fragment, String tag) {
         drawer.closeDrawers();
 
-        FragmentTransaction transaction = getFragmentManager().beginTransaction();
-        transaction.replace(R.id.container, fragment, tag);
-        transaction.commit();
+        getFragmentManager()
+                .beginTransaction()
+                .setCustomAnimations(
+                        R.animator.card_flip_right_in, R.animator.card_flip_right_out,
+                        R.animator.card_flip_left_in, R.animator.card_flip_left_out)
+                .replace(R.id.container, fragment, tag)
+                .commit();
     }
 
     public void onAbout(View view) {

app/src/main/res/animator/card_flip_left_in.xml

@@ -0,0 +1,20 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Before rotating, immediately set the alpha to 0. -->
+    <objectAnimator
+        android:valueFrom="1.0"
+        android:valueTo="0.0"
+        android:propertyName="alpha"
+        android:duration="0" />
+    <objectAnimator
+        android:valueFrom="-180"
+        android:valueTo="0"
+        android:propertyName="rotationY"
+        android:interpolator="@android:interpolator/accelerate_decelerate"
+        android:duration="@integer/card_flip_time_full" />
+    <objectAnimator
+        android:valueFrom="0.0"
+        android:valueTo="1.0"
+        android:propertyName="alpha"
+        android:startOffset="@integer/card_flip_time_half"
+        android:duration="1" />
+</set>

app/src/main/res/animator/card_flip_left_out.xml

@@ -0,0 +1,14 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+    <objectAnimator
+        android:valueFrom="0"
+        android:valueTo="180"
+        android:propertyName="rotationY"
+        android:interpolator="@android:interpolator/accelerate_decelerate"
+        android:duration="@integer/card_flip_time_full" />
+    <objectAnimator
+        android:valueFrom="1.0"
+        android:valueTo="0.0"
+        android:propertyName="alpha"
+        android:startOffset="@integer/card_flip_time_half"
+        android:duration="1" />
+</set>

app/src/main/res/animator/card_flip_right_in.xml

@@ -0,0 +1,19 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+    <objectAnimator
+        android:valueFrom="1.0"
+        android:valueTo="0.0"
+        android:propertyName="alpha"
+        android:duration="0" />
+    <objectAnimator
+        android:valueFrom="180"
+        android:valueTo="0"
+        android:propertyName="rotationY"
+        android:interpolator="@android:interpolator/accelerate_decelerate"
+        android:duration="@integer/card_flip_time_full" />
+    <objectAnimator
+        android:valueFrom="0.0"
+        android:valueTo="1.0"
+        android:propertyName="alpha"
+        android:startOffset="@integer/card_flip_time_half"
+        android:duration="1" />
+</set>

app/src/main/res/animator/card_flip_right_out.xml

@@ -0,0 +1,14 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+    <objectAnimator
+        android:valueFrom="0"
+        android:valueTo="-180"
+        android:propertyName="rotationY"
+        android:interpolator="@android:interpolator/accelerate_decelerate"
+        android:duration="@integer/card_flip_time_full" />
+    <objectAnimator
+        android:valueFrom="1.0"
+        android:valueTo="0.0"
+        android:propertyName="alpha"
+        android:startOffset="@integer/card_flip_time_half"
+        android:duration="1" />
+</set>

app/src/main/res/values/animation.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="card_flip_time_full">800</integer>
+    <integer name="card_flip_time_half">400</integer>
+</resources>

app/src/main/res/values/styles.xml

@@ -12,7 +12,7 @@
 
     <style name="FloatingActionButton" parent="android:Widget.Material.Button">
         <item name="android:background">@drawable/fab_background</item>
-        <item name="android:stateListAnimator">@anim/fab_state_list_animator</item>
+        <item name="android:stateListAnimator">@animator/fab_state_list_animator</item>
         <item name="android:layout_width">56dp</item>
         <item name="android:layout_height">56dp</item>
     </style>