Add API demo for fragment menus.

Change-Id: I85714938861dea06bb72f39dd7d1465c0d3926e4

samples/ApiDemos/src/com/example/android/apis/app/FragmentMenu.java

@@ -0,0 +1,115 @@
+package com.example.android.apis.app;
+
+import com.example.android.apis.R;
+
+import android.app.Activity;
+import android.app.Fragment;
+import android.app.FragmentTransaction;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.View.OnClickListener;
+import android.widget.Button;
+import android.widget.CheckBox;
+import android.widget.TextView;
+
+/**
+ * Demonstrates how fragments can participate in the options menu.
+ */
+public class FragmentMenu extends Activity {
+    Fragment mFragment1;
+    Fragment mFragment2;
+    CheckBox mCheckBox1;
+    CheckBox mCheckBox2;
+    
+    // Update fragment visibility when check boxes are changed.
+    final OnClickListener mClickListener = new OnClickListener() {
+        public void onClick(View v) {
+            updateFragmentVisibility();
+        }
+    };
+    
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.fragment_menu);
+        
+        // Make sure the two menu fragments are created.
+        FragmentTransaction ft = openFragmentTransaction();
+        mFragment1 = findFragmentByTag("f1");
+        if (mFragment1 == null) {
+            mFragment1 = new Menu1Fragment();
+            ft.add(mFragment1, "f1");
+        }
+        mFragment2 = findFragmentByTag("f2");
+        if (mFragment2 == null) {
+            mFragment2 = new Menu2Fragment();
+            ft.add(mFragment2, "f2");
+        }
+        ft.commit();
+        
+        // Watch check box clicks.
+        mCheckBox1 = (CheckBox)findViewById(R.id.menu1);
+        mCheckBox1.setOnClickListener(mClickListener);
+        mCheckBox2 = (CheckBox)findViewById(R.id.menu2);
+        mCheckBox2.setOnClickListener(mClickListener);
+        
+        // Make sure fragments start out with correct visibility.
+        updateFragmentVisibility();
+    }
+    
+    @Override
+    protected void onRestoreInstanceState(Bundle savedInstanceState) {
+        super.onRestoreInstanceState(savedInstanceState);
+        // Make sure fragments are updated after check box view state is restored.
+        updateFragmentVisibility();
+    }
+
+    // Update fragment visibility based on current check box state.
+    void updateFragmentVisibility() {
+        FragmentTransaction ft = openFragmentTransaction();
+        if (mCheckBox1.isChecked()) ft.show(mFragment1);
+        else ft.hide(mFragment1);
+        if (mCheckBox2.isChecked()) ft.show(mFragment2);
+        else ft.hide(mFragment2);
+        ft.commit();
+    }
+    
+    /**
+     * A fragment that displays a menu.  This fragment happens to not
+     * have a UI (it does not implement onCreateView), but it could also
+     * have one if it wanted.
+     */
+    public static class Menu1Fragment extends Fragment {
+        @Override
+        public void onCreate(Bundle savedInstanceState) {
+            super.onCreate(savedInstanceState);
+            setHasOptionsMenu(true);
+        }
+
+        @Override
+        public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+            menu.add("Menu 1a");
+            menu.add("Menu 1b");
+        }
+    }
+
+    /**
+     * Second fragment with a menu.
+     */
+    public static class Menu2Fragment extends Fragment {
+        @Override
+        public void onCreate(Bundle savedInstanceState) {
+            super.onCreate(savedInstanceState);
+            setHasOptionsMenu(true);
+        }
+
+        @Override
+        public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+            menu.add("Menu 2");
+        }
+    }
+}