Add new sample for 101 class on fragments.

The app has a fragment with a list that shows a couple phony
article names and a fragment that displays the phony articles.
They appear side by side on a large screen, but one at a time on smaller screens.

Change-Id: Ic78b772e1c8d1ddbfa6fa3fdb0b54a2363951063

samples/training/basic/FragmentBasics/AndroidManifest.xml

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+<!--
+Copyright (C) 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.
+-->
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.android.fragments"
+    android:versionCode="1"
+    android:versionName="1.0" >
+
+    <uses-sdk android:minSdkVersion="4" android:targetSdkVersion="15" />
+
+    <application
+        android:icon="@drawable/ic_launcher"
+        android:label="@string/app_name" >
+        <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>
+    </application>
+
+</manifest>

samples/training/basic/FragmentBasics/project.properties

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+# This file is automatically generated by Android Tools.
+# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
+#
+# This file must be checked in Version Control Systems.
+#
+# To customize properties used by the Ant build system edit
+# "ant.properties", and override values to adapt the script to your
+# project structure.
+#
+# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
+#proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
+
+# Project target.
+target=android-15

samples/training/basic/FragmentBasics/res/layout-large/news_articles.xml

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+<!--
+Copyright (C) 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.
+-->
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="horizontal"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <fragment android:name="com.example.android.fragments.HeadlinesFragment"
+              android:id="@+id/headlines_fragment"
+              android:layout_weight="1"
+              android:layout_width="0dp"
+              android:layout_height="match_parent" />
+
+    <fragment android:name="com.example.android.fragments.ArticleFragment"
+              android:id="@+id/article_fragment"
+              android:layout_weight="2"
+              android:layout_width="0dp"
+              android:layout_height="match_parent" />
+
+</LinearLayout>

samples/training/basic/FragmentBasics/res/layout/article_view.xml

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+<!--
+Copyright (C) 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.
+-->
+<?xml version="1.0" encoding="utf-8"?>
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/article"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:padding="16dp"
+    android:textSize="18sp" />

samples/training/basic/FragmentBasics/res/layout/news_articles.xml

@@ -0,0 +1,20 @@
+<!--
+Copyright (C) 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.
+-->
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/fragment_container"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />

samples/training/basic/FragmentBasics/res/values/strings.xml

@@ -0,0 +1,19 @@
+<!--
+Copyright (C) 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.
+-->
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">Fragment Basics</string>
+</resources>

samples/training/basic/FragmentBasics/src/com/example/fragments/ArticleFragment.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 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.fragments;
+
+import android.support.v4.app.Fragment;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+public class ArticleFragment extends Fragment {
+    final static String ARG_POSITION = "position";
+    int mCurrentPosition = -1;
+
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
+        Bundle savedInstanceState) {
+
+        // If activity recreated (such as from screen rotate), restore
+        // the previous article selection set by onSaveInstanceState().
+        // This is primarily necessary when in the two-pane layout.
+        if (savedInstanceState != null) {
+            mCurrentPosition = savedInstanceState.getInt(ARG_POSITION);
+        }
+
+        // Inflate the layout for this fragment
+        return inflater.inflate(R.layout.article_view, container, false);
+    }
+
+    @Override
+    public void onStart() {
+        super.onStart();
+
+        // During startup, check if there are arguments passed to the fragment.
+        // onStart is a good place to do this because the layout has already been
+        // applied to the fragment at this point so we can safely call the method
+        // below that sets the article text.
+        Bundle args = getArguments();
+        if (args != null) {
+            // Set article based on argument passed in
+            updateArticleView(args.getInt(ARG_POSITION));
+        } else if (mCurrentPosition != -1) {
+            // Set article based on saved instance state defined during onCreateView
+            updateArticleView(mCurrentPosition);
+        }
+    }
+
+    public void updateArticleView(int position) {
+        TextView article = (TextView) getActivity().findViewById(R.id.article);
+        article.setText(Ipsum.Articles[position]);
+        mCurrentPosition = position;
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+
+        // Save the current article selection in case we need to recreate the fragment
+        outState.putInt(ARG_POSITION, mCurrentPosition);
+    }
+}

samples/training/basic/FragmentBasics/src/com/example/fragments/HeadlinesFragment.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 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.fragments;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.support.v4.app.ListFragment;
+import android.view.View;
+import android.widget.ArrayAdapter;
+import android.widget.ListView;
+
+public class HeadlinesFragment extends ListFragment {
+    OnHeadlineSelectedListener mCallback;
+
+    // The container Activity must implement this interface so the frag can deliver messages
+    public interface OnHeadlineSelectedListener {
+        /** Called by HeadlinesFragment when a list item is selected */
+        public void onArticleSelected(int position);
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        // We need to use a different list item layout for devices older than Honeycomb
+        int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
+                android.R.layout.simple_list_item_activated_1 : android.R.layout.simple_list_item_1;
+
+        // Create an array adapter for the list view, using the Ipsum headlines array
+        setListAdapter(new ArrayAdapter<String>(getActivity(), layout, Ipsum.Headlines));
+    }
+
+    @Override
+    public void onStart() {
+        super.onStart();
+
+        // When in two-pane layout, set the listview to highlight the selected list item
+        // (We do this during onStart because at the point the listview is available.)
+        if (getFragmentManager().findFragmentById(R.id.article_fragment) != null) {
+            getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
+        }
+    }
+
+    @Override
+    public void onAttach(Activity activity) {
+        super.onAttach(activity);
+
+        // This makes sure that the container activity has implemented
+        // the callback interface. If not, it throws an exception.
+        try {
+            mCallback = (OnHeadlineSelectedListener) activity;
+        } catch (ClassCastException e) {
+            throw new ClassCastException(activity.toString()
+                    + " must implement OnHeadlineSelectedListener");
+        }
+    }
+
+    @Override
+    public void onListItemClick(ListView l, View v, int position, long id) {
+        // Notify the parent activity of selected item
+        mCallback.onArticleSelected(position);
+        
+        // Set the item as checked to be highlighted when in two-pane layout
+        getListView().setItemChecked(position, true);
+    }
+}

samples/training/basic/FragmentBasics/src/com/example/fragments/Ipsum.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 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.fragments;
+
+public class Ipsum {
+
+    static String[] Headlines = {
+        "Article One",
+        "Article Two"
+    };
+
+    static String[] Articles = {
+        "Article One\n\nExcepteur pour-over occaecat squid biodiesel umami gastropub, nulla laborum salvia dreamcatcher fanny pack. Ullamco culpa retro ea, trust fund excepteur eiusmod direct trade banksy nisi lo-fi cray messenger bag. Nesciunt esse carles selvage put a bird on it gluten-free, wes anderson ut trust fund twee occupy viral. Laboris small batch scenester pork belly, leggings ut farm-to-table aliquip yr nostrud iphone viral next level. Craft beer dreamcatcher pinterest truffaut ethnic, authentic brunch. Esse single-origin coffee banksy do next level tempor. Velit synth dreamcatcher, magna shoreditch in american apparel messenger bag narwhal PBR ennui farm-to-table.",
+        "Article Two\n\nVinyl williamsburg non velit, master cleanse four loko banh mi. Enim kogi keytar trust fund pop-up portland gentrify. Non ea typewriter dolore deserunt Austin. Ad magna ethical kogi mixtape next level. Aliqua pork belly thundercats, ut pop-up tattooed dreamcatcher kogi accusamus photo booth irony portland. Semiotics brunch ut locavore irure, enim etsy laborum stumptown carles gentrify post-ironic cray. Butcher 3 wolf moon blog synth, vegan carles odd future."
+    };
+}

samples/training/basic/FragmentBasics/src/com/example/fragments/MainActivity.java

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+/*
+ * Copyright (C) 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.fragments;
+
+import android.os.Bundle;
+import android.support.v4.app.FragmentActivity;
+import android.support.v4.app.FragmentTransaction;
+
+public class MainActivity extends FragmentActivity 
+        implements HeadlinesFragment.OnHeadlineSelectedListener {
+
+    /** Called when the activity is first created. */
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.news_articles);
+
+        // Check whether the activity is using the layout version with
+        // the fragment_container FrameLayout. If so, we must add the first fragment
+        if (findViewById(R.id.fragment_container) != null) {
+
+            // However, if we're being restored from a previous state,
+            // then we don't need to do anything and should return or else
+            // we could end up with overlapping fragments.
+            if (savedInstanceState != null) {
+                return;
+            }
+
+            // Create an instance of ExampleFragment
+            HeadlinesFragment firstFragment = new HeadlinesFragment();
+
+            // In case this activity was started with special instructions from an Intent,
+            // pass the Intent's extras to the fragment as arguments
+            firstFragment.setArguments(getIntent().getExtras());
+
+            // Add the fragment to the 'fragment_container' FrameLayout
+            getSupportFragmentManager().beginTransaction()
+                    .add(R.id.fragment_container, firstFragment).commit();
+        }
+    }
+
+    public void onArticleSelected(int position) {
+        // The user selected the headline of an article from the HeadlinesFragment
+
+        // Capture the article fragment from the activity layout
+        ArticleFragment articleFrag = (ArticleFragment)
+                getSupportFragmentManager().findFragmentById(R.id.article_fragment);
+
+        if (articleFrag != null) {
+            // If article frag is available, we're in two-pane layout...
+
+            // Call a method in the ArticleFragment to update its content
+            articleFrag.updateArticleView(position);
+
+        } else {
+            // If the frag is not available, we're in the one-pane layout and must swap frags...
+
+            // Create fragment and give it an argument for the selected article
+            ArticleFragment newFragment = new ArticleFragment();
+            Bundle args = new Bundle();
+            args.putInt(ArticleFragment.ARG_POSITION, position);
+            newFragment.setArguments(args);
+            FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
+
+            // Replace whatever is in the fragment_container view with this fragment,
+            // and add the transaction to the back stack so the user can navigate back
+            transaction.replace(R.id.fragment_container, newFragment);
+            transaction.addToBackStack(null);
+
+            // Commit the transaction
+            transaction.commit();
+        }
+    }
+}