How to use Fragments in Android

Question

EDIT ::: Please refer to my answer below...

Question:::

I am very new to using Fragments in Android and I am completely messed up.

I am just trying t

Answer 1

Okie... Finally found a solution. Probably, it wasn't much of a change.

Check out the code below...

activity_main.XML

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <fragment
        android:id="@+id/fragment_content_1"
        android:name="com.example.fragmentexample.Fragment_1"
        android:layout_width="0dip"
        android:layout_weight="0.50"
        android:layout_height="fill_parent" >
    </fragment>

    <fragment
        android:id="@+id/fragment_content_2"
        android:name="com.example.fragmentexample.Fragment_2"
        android:layout_width="0dip"
        android:layout_weight="0.50"
        android:layout_height="fill_parent" >

        <!-- Preview: layout=@layout/fragment_basic -->
    </fragment>

</LinearLayout>

The layouts of fragment_fragment_1 and fragment_fragment_2 remain the same.

Fragment_1.Java

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 && f2.isInLayout())
                    {
                        f2.setName(name);
                    }

                    Activity activity = getActivity();

                    if(activity != null)
                    {
                        Toast.makeText(activity, "Say&ing Hi in Progress...", Toast.LENGTH_LONG).show();
                    }
                }
            });

            return view;


        }

    }

Fragment_2.Java

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);
    }

}

Here is the ScreenShot...

Answer 2

Please edit your activity_main.XML AS as follows.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent" >

<fragment
    android:id="@+id/fragment_content_1"
    android:name="com.example.fragmentexample.fragment_fragment_1"
    class="com.example.fragmentexample.fragment_fragment_1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
</fragment>

<fragment
    android:id="@+id/fragment_content_2"
    android:name="com.example.fragmentexample.fragment_fragment_2"
    class="com.example.fragmentexample.fragment_fragment_2"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <!-- Preview: layout=@layout/fragment_basic -->
</fragment>
</LinearLayout>

Answer 3

This is the classic case of Communication between two Fragments.
But let's cover more basic things first.

Skeleton of the Fragments

FirstFragment

EditText
Button

public class FirstFragment extends Fragment{

      private EditText editext;
      private Button button;

      public static FirstFragment getInstance(){  
           return new FirstFragment();
      }

      public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle bundle){
           View view = inflater.inflate(R.Layout.fragment1,parent,false);
           editext = (EditText)view.findViewById(R.id.editText)
           button = (Button)view.findViewById(R.id.button)
           return view;               

      }

}

SecondFragment

TextView

public class SecondFragment extends Fragment{

      private TextView textView;

      public static SecondFragment getInstance(){  
           return new SecondFragment();
      }

      public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle bundle){
           View view = inflater.inflate(R.Layout.fragment2,parent,false);
           textView = (TextView)view.findViewById(R.id.editText)
           return view;               

      }

      public void showMessage(String msg)
      {
           textView.setText(msg)
      }

}

How to createInstance of Fragments

FirstFragment fragmne1 = FirstFragment.getInstance();
SecondFragment fragmne1 = SecondFragment.getInstance();

How to Add them in the Activity?

getSupportFragmentManager()
         .beginTransaction()
         .add(R.id.placeholder1,fragment1,"TAG1")
         .add(R.id.placeholder2,fragment2,"TAG2")
         .commit();

Now the communication Part

Create an Interface

public interface FragmentListener{
     public void buttonClicked();
}

Implement this interface in the Activity and override the method

public MyActivity extends AppcompatActivity implements MyFragmentListener{

     @Override
     public void buttonClicked(){
          fragment2.showMessage(String msg);
     }

}

Send data from Fragment

1. initialize the listener in the FirstFragment
2. call interface method on Button click.

The final structure of FirstFragment

public class FirstFragment extends Fragment{

      private EditText editext;
      private Button button;
      private MyFragmentListener listener;

      public static FirstFragment getInstance(){  
           return new FirstFragment();
      }

      public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle bundle){
           View view = inflater.inflate(R.Layout.fragment1,parent,false);
           editext = (EditText)view.findViewById(R.id.editText)
           button = (Button)view.findViewById(R.id.button)

           // button click method 
           listener.buttonClicked(editText.getText().toString());

           return view;               

      }

      @Override 
      public void onAttach(Context context){
           listener = (MyFragmentListener)context;
      }

}

Answer 4

You need to add an empty public constructor to your Fragments, like it says in the stack trace:

public class Fragment_2 extends Fragment{

    public Frament_2() {
        //BLAH!
    }

    // The rest of your code

}