In My App Using  One Activity And I Am Using Two Fragment.  How Can We Swap The Fragment  In Activity?

* First Create Project With Empty Activity.

*After That Create Two Fragment.

* Create This Code MainActivity.XML Page

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context="waytofeed.wapptech.com.demo15.MainActivity"
   android:orientation="vertical">
<Button
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:textSize="35dp"
       android:text="Click"
       android:id="@+id/button"/>
fragment
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:name="waytofeed.wapptech.com.demo15.page1"
       android:layout_weight="1"
       android:id="@+id/frag1">
       </fragment>
fragment
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:name="waytofeed.wapptech.com.demo15.page2"
       android:layout_weight="1"
       android:id="@+id/frag2">
       fragment>
</LinearLayout>

After That In MainActivity.java File Add This Code:)

public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
   Button button;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
       button=findViewById(R.id.button);
       button.setOnClickListener(this);
   }
   @Override
   public void onClick(View view)
   {
       Fragment fm= new page2();
       FragmentTransaction ft=getFragmentManager().beginTransaction();
       ft.replace(R.id.frag1,fm);
       ft.commit();
   }
}

Always Remember Import This Package All Java File:)

import android.app.Fragment;

See demo: https://www.youtube.com/watch?v=-O6Keneh_5k

Github Link: https://github.com/Sudarshan101/swapFragment