Dynamic work with fragments?

Question

Java

On pressing the button, a fragment should appear, but nothing happens, what's the problem?
Here is the snippet code:

public class ProfileFragment extends Fragment {


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_profile,null);
    }

}

Activity code with onClick:

public class WorkActivity extends AppCompatActivity {
 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_work);      
    }
public void onClick(View view) {
        Fragment  profileFragment = new Fragment();
        FragmentTransaction fragt = getFragmentManager().beginTransaction();
        fragt.add(R.id.mainLayout, profileFragment);
        fragt.commit();

    }
}

And the layout file itself:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Activity.WorkActivity">
    <include layout="@layout/toolbar"
        android:id="@+id/toolbar"></include>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/mainLayout"
        android:layout_alignTop="@+id/button"
        android:orientation="horizontal"></LinearLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/button"
        android:layout_below="@+id/toolbar"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginLeft="45dp"
        android:onClick="onClick"
        android:layout_marginStart="45dp" />

</RelativeLayout>

Answer 1

1) Are you using Fragment from support library( android.support.v4 ) or normal fragment ?
If from the library , then use getFragmentSupportManager()instead getFragmentManager().beginTransaction()
of 2) Fragment profileFragment = new Fragment();
Masterpiece. Can you still create an instance of your fragment ?
3) The onClick method is called ( check with logs )?
4)

And the layout file itself:

Is it the layout of an activity or a fragment ? What is it R.id.mainLayout? Is it a FrameLayout or a fragment that is inside the layout of the activity ?
5) Maybe the background of the fragment is transparent and you can't see that the fragment appears?

Answer 2

Try replacing the code with this:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment, container, false);
}