title: How to use Fragments in Android
body: <p>EDIT ::: Please refer to my answer below...</p>
  
  <p>Question:::</p>
  
  <p>I am very new to using Fragments in Android and I am completely messed up.</p>
  
  <p>I am just trying to build a simple sample application that uses Fragments. My scenario is, I have two fragments in my main activity. The first fragment has an edittext and a button. The second fragment has a textview. When I enter a name in the edittext and click on the button, the textview in the second fragment should display the name entered in the edittext of the first fragment.</p>
  
  <p>I am using the static assignment of fragments (assigning fragments in XML).</p>
  
  <p>Please refer to the XML files and Code below...</p>
  
  <p>activity_main.XML</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent" &gt;
  
      &lt;fragment
          android:id="@+id/fragment_content_1"
          android:name="com.example.fragmentexample.fragment_fragment_1"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent" &gt;
      &lt;/fragment&gt;
  
      &lt;fragment
          android:id="@+id/fragment_content_2"
          android:name="com.example.fragmentexample.fragment_fragment_2"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent" &gt;
  
          &lt;!-- Preview: layout=@layout/fragment_basic --&gt;
      &lt;/fragment&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>fragment_fragment_1.XML</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:orientation="vertical" &gt;
  
      &lt;EditText
          android:id="@+id/edtxtPersonName"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:ems="10"
          android:inputType="textPersonName" &gt;
  
          &lt;requestFocus /&gt;
      &lt;/EditText&gt;
  
      &lt;Button
          android:id="@+id/btnSayHi"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="Say Hi" /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>fragment_fragment_2.XML</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:orientation="vertical" &gt;
  
      &lt;TextView
          android:id="@+id/txtViewResult"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="I will say Hi" /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>Java Files :::</p>
  
  <p>MainActivity.Java</p>
  
  <pre><code>    public class MainActivity extends Activity {
  
          @Override
          protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_main);
          }
  
          @Override
          public boolean onCreateOptionsMenu(Menu menu) {
              // Inflate the menu; this adds items to the action bar if it is present.
              getMenuInflater().inflate(R.menu.activity_main, menu);
              return true;
          }
  
      }
  </code></pre>
  
  <p>Fragment_1.Java</p>
  
  <pre><code>public class Fragment_1 extends Fragment{
  
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container,
              Bundle savedInstanceState) {
          // TODO Auto-generated method stub      
  
          View view = inflater.inflate(R.layout.fragment_fragment_1, container, false);
  
          final EditText edtxtPersonName_Fragment = (EditText) view.findViewById(R.id.edtxtPersonName);
          Button btnSayHi_Fragment = (Button) view.findViewById(R.id.btnSayHi);
  
          btnSayHi_Fragment.setOnClickListener(new OnClickListener() {
  
              @Override
              public void onClick(View v) {
                  // TODO Auto-generated method stub
  
                  String name = edtxtPersonName_Fragment.getText().toString();
  
                  FragmentManager fm = getFragmentManager();
                  Fragment_2 f2 = (Fragment_2) fm.findFragmentById(R.id.fragment_content_2);
  
                  if(f2 != null &amp;&amp; f2.isInLayout())
                  {
                      f2.setName(name);
                  }
  
                  Activity activity = getActivity();
  
                  if(activity != null)
                  {
                      Toast.makeText(activity, "Say&amp;ing Hi in Progress...", Toast.LENGTH_LONG).show();
                  }
              }
          });
  
          return view;
  
  
      }
  
  }
  </code></pre>
  
  <p>Fragment_2.Java</p>
  
  <pre><code>public class Fragment_2 extends Fragment{
  
      View view;
  
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container,
              Bundle savedInstanceState) {
          // TODO Auto-generated method stub
  
          view = inflater.inflate(R.layout.fragment_fragment_2, container, false);        
          return view;
      }
  
      public void setName(String name)
      {
          TextView txtName = (TextView) view.findViewById(R.id.txtViewResult);
          txtName.setText("Hi " + name);
      }
  
  }
  </code></pre>
  
  <p>When I run the application, there are whole lot of exceptions.. Here is the logcat trace..</p>
  
  <pre><code>04-16 15:06:48.781: E/AndroidRuntime(420): FATAL EXCEPTION: main
  04-16 15:06:48.781: E/AndroidRuntime(420): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fragmentexample/com.example.fragmentexample.MainActivity}: android.view.InflateException: Binary XML file line #5: Error inflating class fragment
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.ActivityThread.access$500(ActivityThread.java:122)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.os.Handler.dispatchMessage(Handler.java:99)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.os.Looper.loop(Looper.java:132)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.ActivityThread.main(ActivityThread.java:4123)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at java.lang.reflect.Method.invokeNative(Native Method)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at java.lang.reflect.Method.invoke(Method.java:491)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at dalvik.system.NativeStart.main(Native Method)
  04-16 15:06:48.781: E/AndroidRuntime(420): Caused by: android.view.InflateException: Binary XML file line #5: Error inflating class fragment
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:688)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.view.LayoutInflater.rInflate(LayoutInflater.java:724)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.view.LayoutInflater.inflate(LayoutInflater.java:391)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.view.LayoutInflater.inflate(LayoutInflater.java:347)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:223)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Activity.setContentView(Activity.java:1786)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at com.example.fragmentexample.MainActivity.onCreate(MainActivity.java:12)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Activity.performCreate(Activity.java:4397)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)
  04-16 15:06:48.781: E/AndroidRuntime(420):  ... 11 more
  04-16 15:06:48.781: E/AndroidRuntime(420): Caused by: android.app.Fragment$InstantiationException: Unable to instantiate fragment com.example.fragmentexample.fragment_fragment_1: make sure class name exists, is public, and has an empty constructor that is public
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Fragment.instantiate(Fragment.java:567)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Fragment.instantiate(Fragment.java:535)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Activity.onCreateView(Activity.java:4168)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:664)
  04-16 15:06:48.781: E/AndroidRuntime(420):  ... 21 more
  04-16 15:06:48.781: E/AndroidRuntime(420): Caused by: java.lang.ClassNotFoundException: com.example.fragmentexample.fragment_fragment_1 in loader dalvik.system.PathClassLoader[/data/app/com.example.fragmentexample-1.apk]
  04-16 15:06:48.781: E/AndroidRuntime(420):  at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:251)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at java.lang.ClassLoader.loadClass(ClassLoader.java:540)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at java.lang.ClassLoader.loadClass(ClassLoader.java:500)
  04-16 15:06:48.781: E/AndroidRuntime(420):  at android.app.Fragment.instantiate(Fragment.java:557)
  04-16 15:06:48.781: E/AndroidRuntime(420):  ... 24 more
  </code></pre>
  
  <p>I have seen examples on how to do it, but couldn't figure it out. Please point the regions where i am doing it wrong, and also please post the correct way of doing it.</p>
  
  <p>Thanks a lot for your time...</p>
  
  <p>EDIT :::</p>
  
  <p>I have changed the MainActivity.java to extend FragmentActivity instead of Activity and also changed the android:name values in the activity_main.xml to point to Java Files instead of fragments...</p>
  
  <p>I get the following exceptions :::</p>
  
  <pre><code>04-16 15:29:43.821: E/AndroidRuntime(563): FATAL EXCEPTION: main
  04-16 15:29:43.821: E/AndroidRuntime(563): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fragmentexample/com.example.fragmentexample.MainActivity}: android.view.InflateException: Binary XML file line #5: Error inflating class fragment
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.ActivityThread.access$500(ActivityThread.java:122)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.os.Handler.dispatchMessage(Handler.java:99)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.os.Looper.loop(Looper.java:132)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.ActivityThread.main(ActivityThread.java:4123)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at java.lang.reflect.Method.invokeNative(Native Method)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at java.lang.reflect.Method.invoke(Method.java:491)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at dalvik.system.NativeStart.main(Native Method)
  04-16 15:29:43.821: E/AndroidRuntime(563): Caused by: android.view.InflateException: Binary XML file line #5: Error inflating class fragment
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:688)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.view.LayoutInflater.rInflate(LayoutInflater.java:724)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.view.LayoutInflater.inflate(LayoutInflater.java:391)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.view.LayoutInflater.inflate(LayoutInflater.java:347)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:223)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.Activity.setContentView(Activity.java:1786)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at com.example.fragmentexample.MainActivity.onCreate(MainActivity.java:13)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.Activity.performCreate(Activity.java:4397)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)
  04-16 15:29:43.821: E/AndroidRuntime(563):  ... 11 more
  04-16 15:29:43.821: E/AndroidRuntime(563): Caused by: java.lang.ClassCastException: com.example.fragmentexample.Fragment_1 cannot be cast to android.support.v4.app.Fragment
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.support.v4.app.Fragment.instantiate(Fragment.java:394)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.support.v4.app.Fragment.instantiate(Fragment.java:369)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:272)
  04-16 15:29:43.821: E/AndroidRuntime(563):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:660)
  04-16 15:29:43.821: E/AndroidRuntime(563):  ... 21 more
  </code></pre>
  
  <p>Here is the changed XML File of activity_main.xml</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent" &gt;
  
      &lt;fragment
          android:id="@+id/fragment_content_1"
          android:name="com.example.fragmentexample.Fragment_1"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent" &gt;
      &lt;/fragment&gt;
  
      &lt;fragment
          android:id="@+id/fragment_content_2"
          android:name="com.example.fragmentexample.Fragment_2"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent" &gt;
  
          &lt;!-- Preview: layout=@layout/fragment_basic --&gt;
      &lt;/fragment&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>