The Fragment activity not attaching to main

Question

I am trying fragments for the first time. I have read all the developer documents but still I am unable to figure out why my fragment is not attaching to the main activity. following is my code

I am only getting my main activity's layout. No fragment's layout

the main activity xml file

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/relative_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
tools:context="com.attendancerecord.HomePage"
tools:ignore="MergeRootFrame">

    <HorizontalScrollView
        android:id="@+id/scroll2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="200dp">
    </HorizontalScrollView>

</RelativeLayout>

my main.java file

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home_page);

    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    HomePage_Fragment myfragment = new HomePage_Fragment();

    ft.add(R.id.scroll2, myfragment);

    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
    ft.commit();
    }

my fragment.java file

 public class HomePage_Fragment extends Fragment {

     @Override
     public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        SQLiteDatabase db = getActivity().openOrCreateDatabase("DATABASE",android.content.Context.MODE_PRIVATE ,null);

        db.execSQL("CREATE TABLE IF NOT EXISTS ATTENDANCE_RECORD(NAME VARCHAR, ATTENDED integer, " +
                "TOTAL integer, BUNKS integer, PERCENTAGE float)");

       for(int i=0;i<num_subjects;i++){           //initializing of num_subjects is done (long code)

       db.execSQL("INSERT INTO ATTENDANCE_RECORD VALUES( '"+name_subjects[i]+"', "+0+","+0+", "+0+", "+0.0+" )");

         }
      }


public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstance){

    View view= inflater.inflate(R.layout.fragment_home_page,null);
    TableLayout tableLayout = (TableLayout)view.findViewById(R.id.record);

    TableRow tableRow;
    TextView textView;

    SQLiteDatabase db = getActivity().openOrCreateDatabase("DATABASE",android.content.Context.MODE_PRIVATE ,null);

    Cursor c=db.rawQuery("SELECT * FROM ATTENDANCE_RECORD", null);
    c.moveToFirst();

    for(int i=0;i<num_subjects;i++){

        tableRow = new TableRow(getActivity());

        for(int j=0;j<5;j++){

            textView = new TextView(getActivity());
            switch(j){

            case 0: textView.setText(c.getString(c.getColumnIndex("NAME")));
                    break;

            case 1: textView.setText(String.valueOf(c.getString(c.getColumnIndex("ATTENDED"))));
                    break;

            case 2: textView.setText(String.valueOf(c.getInt(c.getColumnIndex("TOTAL"))));
                    break;

            case 3: textView.setText(String.valueOf(c.getInt(c.getColumnIndex("BUNKS"))));
                    break;

            case 4: textView.setText(String.valueOf(c.getFloat(c.getColumnIndex("PERCENTAGE"))));
                    break;

            }

            textView.setPadding(15, 25, 15, 25);

            tableRow.addView(textView, new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, 
                            TableRow.LayoutParams.WRAP_CONTENT, 0));
        }

        c.moveToNext();

        tableLayout.addView(tableRow);

    }

    c.close();



    return inflater.inflate(R.layout.fragment_home_page,container,false);


}

}

My fragment_home_page.xml

 <RelativeLayout

xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
tools:context="com.attendancerecord.HomePage$PlaceholderFragment" >


  <TableLayout

    android:id="@+id/record"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true">

  </TableLayout>


</RelativeLayout>

Answer 1

In Activity onCreate() ,

if(saveInstanceState == null)
{
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    HomePage_Fragment myfragment = new HomePage_Fragment();

    ft.add(R.id.scroll2, myfragment);

    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
    ft.commit();
}

In Fragment onCreateView() ,

    View view = inflater.inflate(R.layout.fragment_home_page, container, false);

The last line of onCreateView() is currently incorrect, use

    return view;

And I'm not sure if the HorizonalScrollView actually qualifies as a Container, I think you need to embed a FrameLayout into it and use THAT as the FragmentContainer.

Answer 2

One issue I have spotted is that you are returning a newly inflated View from your onCreateView() method, rather than the View that you've already created earlier and have been working with.

To fix this, simply return view; instead of your current return statement.

Also, you are also using wrap_content for your height and width of your main Activity layout elements when the Fragment you are creating might not have a height and width. As such you might never see anything. I would suggest using match_parent for the two elements in your main activity instead.

I hope this helps.