Retroactively add EffectiveNavigation and TabCompat sample code.

This sample code was launched with the Implementing Effective Navigation and
Creating Backward-Compatible UIs training classes, but the source was never
added to AOSP. This retroactively adds the source, unmodified.

Change-Id: If6face5a0548107f7fd273e466b1ced2790f4f3a

13 files changed, 554 insertions, 0 deletions

diff --git a/samples/training/EffectiveNavigation/AndroidManifest.xml b/samples/training/EffectiveNavigation/AndroidManifest.xml
new file mode 100755
index 000000000..b1e4e11f3
--- /dev/null
+++ b/samples/training/EffectiveNavigation/AndroidManifest.xml
@@ -0,0 +1,38 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.android.effectivenavigation"
+    android:versionCode="1"
+    android:versionName="1.0">
+
+    <uses-sdk android:minSdkVersion="14" />
+
+    <application android:label="@string/app_name"
+        android:icon="@drawable/ic_launcher"
+        android:theme="@android:style/Theme.Holo.Light.DarkActionBar">
+
+        <activity android:name=".MainActivity" android:label="@string/app_name">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+        <activity android:name=".CollectionDemoActivity" android:label="@string/demo_collection" />
+
+    </application>
+</manifest>
diff --git a/samples/training/EffectiveNavigation/res/drawable-hdpi/ic_launcher.png b/samples/training/EffectiveNavigation/res/drawable-hdpi/ic_launcher.png
new file mode 100644
index 000000000..d2dae4c48
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/drawable-hdpi/ic_launcher.png
diff --git a/samples/training/EffectiveNavigation/res/drawable-ldpi/ic_launcher.png b/samples/training/EffectiveNavigation/res/drawable-ldpi/ic_launcher.png
new file mode 100644
index 000000000..d30b9651a
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/drawable-ldpi/ic_launcher.png
diff --git a/samples/training/EffectiveNavigation/res/drawable-mdpi/ic_launcher.png b/samples/training/EffectiveNavigation/res/drawable-mdpi/ic_launcher.png
new file mode 100644
index 000000000..66253457d
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/drawable-mdpi/ic_launcher.png
diff --git a/samples/training/EffectiveNavigation/res/drawable-xhdpi/ic_launcher.png b/samples/training/EffectiveNavigation/res/drawable-xhdpi/ic_launcher.png
new file mode 100644
index 000000000..67331ceb0
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/drawable-xhdpi/ic_launcher.png
diff --git a/samples/training/EffectiveNavigation/res/layout/activity_collection_demo.xml b/samples/training/EffectiveNavigation/res/layout/activity_collection_demo.xml
new file mode 100755
index 000000000..e34f471ff
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/layout/activity_collection_demo.xml
@@ -0,0 +1,35 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/pager"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <!--
+    This title strip will display the currently visible page title, as well as the page
+    titles for adjacent pages.
+    -->
+    <android.support.v4.view.PagerTitleStrip android:id="@+id/pager_title_strip"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="top"
+        android:background="#33b5e5"
+        android:textColor="#fff"
+        android:paddingTop="4dp"
+        android:paddingBottom="4dp" />
+
+</android.support.v4.view.ViewPager>
diff --git a/samples/training/EffectiveNavigation/res/layout/activity_main.xml b/samples/training/EffectiveNavigation/res/layout/activity_main.xml
new file mode 100755
index 000000000..339b592d5
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/layout/activity_main.xml
@@ -0,0 +1,20 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/pager"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />
diff --git a/samples/training/EffectiveNavigation/res/layout/fragment_collection_object.xml b/samples/training/EffectiveNavigation/res/layout/fragment_collection_object.xml
new file mode 100644
index 000000000..945bf066b
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/layout/fragment_collection_object.xml
@@ -0,0 +1,23 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+  
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+  
+      http://www.apache.org/licenses/LICENSE-2.0
+  
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@android:id/text1"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:gravity="center"
+    android:textSize="128sp"
+    android:padding="32dp" />
diff --git a/samples/training/EffectiveNavigation/res/layout/fragment_section_dummy.xml b/samples/training/EffectiveNavigation/res/layout/fragment_section_dummy.xml
new file mode 100644
index 000000000..1c678859e
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/layout/fragment_section_dummy.xml
@@ -0,0 +1,23 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+  
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+  
+      http://www.apache.org/licenses/LICENSE-2.0
+  
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@android:id/text1"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:gravity="center"
+    android:textSize="24sp"
+    android:padding="32dp" />
diff --git a/samples/training/EffectiveNavigation/res/layout/fragment_section_launchpad.xml b/samples/training/EffectiveNavigation/res/layout/fragment_section_launchpad.xml
new file mode 100644
index 000000000..186b2f2a9
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/layout/fragment_section_launchpad.xml
@@ -0,0 +1,39 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+  
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+  
+      http://www.apache.org/licenses/LICENSE-2.0
+  
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <LinearLayout android:orientation="vertical"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center">
+
+        <Button android:id="@+id/demo_collection_button"
+            android:layout_width="300dp"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="16dp"
+            android:text="@string/demo_collection"/>
+
+        <Button android:id="@+id/demo_external_activity"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="@string/demo_external_activity" />
+
+    </LinearLayout>
+
+</FrameLayout>
diff --git a/samples/training/EffectiveNavigation/res/values/strings.xml b/samples/training/EffectiveNavigation/res/values/strings.xml
new file mode 100755
index 000000000..4ea2dbb3b
--- /dev/null
+++ b/samples/training/EffectiveNavigation/res/values/strings.xml
@@ -0,0 +1,24 @@
+<!--
+  Copyright 2012 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  -->
+
+<resources>
+    <string name="app_name">Effective Navigation</string>
+
+    <string name="dummy_section_text">Section %1d is just a dummy section.</string>
+
+    <string name="demo_external_activity">Demo External Activity</string>
+    <string name="demo_collection">Demo Collection</string>
+</resources>
diff --git a/samples/training/EffectiveNavigation/src/com/example/android/effectivenavigation/CollectionDemoActivity.java b/samples/training/EffectiveNavigation/src/com/example/android/effectivenavigation/CollectionDemoActivity.java
new file mode 100755
index 000000000..641d1a493
--- /dev/null
+++ b/samples/training/EffectiveNavigation/src/com/example/android/effectivenavigation/CollectionDemoActivity.java
@@ -0,0 +1,148 @@
+/*
+ * Copyright 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.effectivenavigation;
+
+import android.app.ActionBar;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentActivity;
+import android.support.v4.app.FragmentManager;
+import android.support.v4.app.FragmentStatePagerAdapter;
+import android.support.v4.app.NavUtils;
+import android.support.v4.app.TaskStackBuilder;
+import android.support.v4.view.ViewPager;
+import android.view.LayoutInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+public class CollectionDemoActivity extends FragmentActivity {
+
+    /**
+     * The {@link android.support.v4.view.PagerAdapter} that will provide fragments representing
+     * each object in a collection. We use a {@link android.support.v4.app.FragmentStatePagerAdapter}
+     * derivative, which will destroy and re-create fragments as needed, saving and restoring their
+     * state in the process. This is important to conserve memory and is a best practice when
+     * allowing navigation between objects in a potentially large collection.
+     */
+    DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
+
+    /**
+     * The {@link android.support.v4.view.ViewPager} that will display the object collection.
+     */
+    ViewPager mViewPager;
+
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_collection_demo);
+
+        // Create an adapter that when requested, will return a fragment representing an object in
+        // the collection.
+        // 
+        // ViewPager and its adapters use support library fragments, so we must use
+        // getSupportFragmentManager.
+        mDemoCollectionPagerAdapter = new DemoCollectionPagerAdapter(getSupportFragmentManager());
+
+        // Set up action bar.
+        final ActionBar actionBar = getActionBar();
+
+        // Specify that the Home button should show an "Up" caret, indicating that touching the
+        // button will take the user one step up in the application's hierarchy.
+        actionBar.setDisplayHomeAsUpEnabled(true);
+
+        // Set up the ViewPager, attaching the adapter.
+        mViewPager = (ViewPager) findViewById(R.id.pager);
+        mViewPager.setAdapter(mDemoCollectionPagerAdapter);
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case android.R.id.home:
+                // This is called when the Home (Up) button is pressed in the action bar.
+                // Create a simple intent that starts the hierarchical parent activity and
+                // use NavUtils in the Support Package to ensure proper handling of Up.
+                Intent upIntent = new Intent(this, MainActivity.class);
+                if (NavUtils.shouldUpRecreateTask(this, upIntent)) {
+                    // This activity is not part of the application's task, so create a new task
+                    // with a synthesized back stack.
+                    TaskStackBuilder.from(this)
+                            // If there are ancestor activities, they should be added here.
+                            .addNextIntent(upIntent)
+                            .startActivities();
+                    finish();
+                } else {
+                    // This activity is part of the application's task, so simply
+                    // navigate up to the hierarchical parent activity.
+                    NavUtils.navigateUpTo(this, upIntent);
+                }
+                return true;
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
+    /**
+     * A {@link android.support.v4.app.FragmentStatePagerAdapter} that returns a fragment
+     * representing an object in the collection.
+     */
+    public static class DemoCollectionPagerAdapter extends FragmentStatePagerAdapter {
+
+        public DemoCollectionPagerAdapter(FragmentManager fm) {
+            super(fm);
+        }
+
+        @Override
+        public Fragment getItem(int i) {
+            Fragment fragment = new DemoObjectFragment();
+            Bundle args = new Bundle();
+            args.putInt(DemoObjectFragment.ARG_OBJECT, i + 1); // Our object is just an integer :-P
+            fragment.setArguments(args);
+            return fragment;
+        }
+
+        @Override
+        public int getCount() {
+            // For this contrived example, we have a 100-object collection.
+            return 100;
+        }
+
+        @Override
+        public CharSequence getPageTitle(int position) {
+            return "OBJECT " + (position + 1);
+        }
+    }
+
+    /**
+     * A dummy fragment representing a section of the app, but that simply displays dummy text.
+     */
+    public static class DemoObjectFragment extends Fragment {
+
+        public static final String ARG_OBJECT = "object";
+
+        @Override
+        public View onCreateView(LayoutInflater inflater, ViewGroup container,
+                Bundle savedInstanceState) {
+            View rootView = inflater.inflate(R.layout.fragment_collection_object, container, false);
+            Bundle args = getArguments();
+            ((TextView) rootView.findViewById(android.R.id.text1)).setText(
+                    Integer.toString(args.getInt(ARG_OBJECT)));
+            return rootView;
+        }
+    }
+}
diff --git a/samples/training/EffectiveNavigation/src/com/example/android/effectivenavigation/MainActivity.java b/samples/training/EffectiveNavigation/src/com/example/android/effectivenavigation/MainActivity.java
new file mode 100755
index 000000000..a560ee4e4
--- /dev/null
+++ b/samples/training/EffectiveNavigation/src/com/example/android/effectivenavigation/MainActivity.java
@@ -0,0 +1,204 @@
+/*
+ * Copyright 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.effectivenavigation;
+
+import android.app.ActionBar;
+import android.app.FragmentTransaction;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentActivity;
+import android.support.v4.app.FragmentManager;
+import android.support.v4.app.FragmentPagerAdapter;
+import android.support.v4.view.ViewPager;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
+
+    /**
+     * The {@link android.support.v4.view.PagerAdapter} that will provide fragments for each of the
+     * three primary sections of the app. We use a {@link android.support.v4.app.FragmentPagerAdapter}
+     * derivative, which will keep every loaded fragment in memory. If this becomes too memory
+     * intensive, it may be best to switch to a {@link android.support.v4.app.FragmentStatePagerAdapter}.
+     */
+    AppSectionsPagerAdapter mAppSectionsPagerAdapter;
+
+    /**
+     * The {@link ViewPager} that will display the three primary sections of the app, one at a
+     * time.
+     */
+    ViewPager mViewPager;
+
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        // Create the adapter that will return a fragment for each of the three primary sections
+        // of the app.
+        mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());
+
+        // Set up the action bar.
+        final ActionBar actionBar = getActionBar();
+
+        // Specify that the Home/Up button should not be enabled, since there is no hierarchical
+        // parent.
+        actionBar.setHomeButtonEnabled(false);
+
+        // Specify that we will be displaying tabs in the action bar.
+        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
+
+        // Set up the ViewPager, attaching the adapter and setting up a listener for when the
+        // user swipes between sections.
+        mViewPager = (ViewPager) findViewById(R.id.pager);
+        mViewPager.setAdapter(mAppSectionsPagerAdapter);
+        mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
+            @Override
+            public void onPageSelected(int position) {
+                // When swiping between different app sections, select the corresponding tab.
+                // We can also use ActionBar.Tab#select() to do this if we have a reference to the
+                // Tab.
+                actionBar.setSelectedNavigationItem(position);
+            }
+        });
+
+        // For each of the sections in the app, add a tab to the action bar.
+        for (int i = 0; i < mAppSectionsPagerAdapter.getCount(); i++) {
+            // Create a tab with text corresponding to the page title defined by the adapter.
+            // Also specify this Activity object, which implements the TabListener interface, as the
+            // listener for when this tab is selected.
+            actionBar.addTab(
+                    actionBar.newTab()
+                            .setText(mAppSectionsPagerAdapter.getPageTitle(i))
+                            .setTabListener(this));
+        }
+    }
+
+    @Override
+    public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
+    }
+
+    @Override
+    public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
+        // When the given tab is selected, switch to the corresponding page in the ViewPager.
+        mViewPager.setCurrentItem(tab.getPosition());
+    }
+
+    @Override
+    public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
+    }
+
+    /**
+     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to one of the primary
+     * sections of the app.
+     */
+    public static class AppSectionsPagerAdapter extends FragmentPagerAdapter {
+
+        public AppSectionsPagerAdapter(FragmentManager fm) {
+            super(fm);
+        }
+
+        @Override
+        public Fragment getItem(int i) {
+            switch (i) {
+                case 0:
+                    // The first section of the app is the most interesting -- it offers
+                    // a launchpad into the other demonstrations in this example application.
+                    return new LaunchpadSectionFragment();
+
+                default:
+                    // The other sections of the app are dummy placeholders.
+                    Fragment fragment = new DummySectionFragment();
+                    Bundle args = new Bundle();
+                    args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, i + 1);
+                    fragment.setArguments(args);
+                    return fragment;
+            }
+        }
+
+        @Override
+        public int getCount() {
+            return 3;
+        }
+
+        @Override
+        public CharSequence getPageTitle(int position) {
+            return "Section " + (position + 1);
+        }
+    }
+
+    /**
+     * A fragment that launches other parts of the demo application.
+     */
+    public static class LaunchpadSectionFragment extends Fragment {
+
+        @Override
+        public View onCreateView(LayoutInflater inflater, ViewGroup container,
+                Bundle savedInstanceState) {
+            View rootView = inflater.inflate(R.layout.fragment_section_launchpad, container, false);
+
+            // Demonstration of a collection-browsing activity.
+            rootView.findViewById(R.id.demo_collection_button)
+                    .setOnClickListener(new View.OnClickListener() {
+                        @Override
+                        public void onClick(View view) {
+                            Intent intent = new Intent(getActivity(), CollectionDemoActivity.class);
+                            startActivity(intent);
+                        }
+                    });
+
+            // Demonstration of navigating to external activities.
+            rootView.findViewById(R.id.demo_external_activity)
+                    .setOnClickListener(new View.OnClickListener() {
+                        @Override
+                        public void onClick(View view) {
+                            // Create an intent that asks the user to pick a photo, but using
+                            // FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET, ensures that relaunching
+                            // the application from the device home screen does not return
+                            // to the external activity.
+                            Intent externalActivityIntent = new Intent(Intent.ACTION_PICK);
+                            externalActivityIntent.setType("image/*");
+                            externalActivityIntent.addFlags(
+                                    Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
+                            startActivity(externalActivityIntent);
+                        }
+                    });
+
+            return rootView;
+        }
+    }
+
+    /**
+     * A dummy fragment representing a section of the app, but that simply displays dummy text.
+     */
+    public static class DummySectionFragment extends Fragment {
+
+        public static final String ARG_SECTION_NUMBER = "section_number";
+
+        @Override
+        public View onCreateView(LayoutInflater inflater, ViewGroup container,
+                Bundle savedInstanceState) {
+            View rootView = inflater.inflate(R.layout.fragment_section_dummy, container, false);
+            Bundle args = getArguments();
+            ((TextView) rootView.findViewById(android.R.id.text1)).setText(
+                    getString(R.string.dummy_section_text, args.getInt(ARG_SECTION_NUMBER)));
+            return rootView;
+        }
+    }
+}