First simple Fragment API demo.

Change-Id: I8d21485bc12445fe8a670796ddbc3e5ef57fd390

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

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2010 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.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.View;
+import android.view.ViewGroup;
+import android.view.View.OnClickListener;
+import android.widget.Button;
+import android.widget.TextView;
+
+public class SimpleFragment extends Activity {
+    int mWhichFragment;
+    Fragment mCurFragment;
+    
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.simple_fragment);
+        switchToFragment(0);
+        
+        // Watch for button clicks.
+        Button button = (Button)findViewById(R.id.next);
+        button.setOnClickListener(new OnClickListener() {
+            public void onClick(View v) {
+                switchToFragment(mWhichFragment == 0 ? 1 : 0);
+            }
+        });
+    }
+    
+    void switchToFragment(int which) {
+        mWhichFragment = which;
+        Fragment newFragment = which == 0
+                ? new FirstFragment() : new SecondFragment();
+        FragmentTransaction ft = openFragmentTransaction();
+        if (mCurFragment != null) {
+            ft.remove(mCurFragment);
+        }
+        ft.add(newFragment, R.id.simple_fragment);
+        mCurFragment = newFragment;
+        ft.commit();
+    }
+    
+    class FirstFragment extends Fragment {
+        public View onCreateView(LayoutInflater inflater, ViewGroup container) {
+            return inflater.inflate(R.layout.hello_world, container, false);
+        }
+    }
+    
+    class SecondFragment extends Fragment {
+        public View onCreateView(LayoutInflater inflater, ViewGroup container) {
+            View v = inflater.inflate(R.layout.hello_world, container, false);
+            View tv = v.findViewById(R.id.text);
+            ((TextView)tv).setText("Second Hello World!");
+            return v;
+        }
+    }
+}