Gridlayout support versions less than 4.0

Question

I'm creating a drag and drop functionality for my application and right now am just going through a tutorial to get me accustomed to the basics. I want to be able to run my application on my real device but the version doesn't support 4.0 and above (since the drag and drop uses Gridlayout). It does however support API 8.

I looked around and noticed that people were using the support v7 gridlayout to support lesser versions. How can I implement this into my app? I get the error on my drag_and_drop_app.xml:

<?xml version="1.0" encoding="utf-8"?>
<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnCount="2"
android:columnWidth="300dp"
android:orientation="vertical"
android:rowCount="2"
android:stretchMode="columnWidth" > 

<LinearLayout
    android:id="@+id/topleft"
    android:layout_width="160dp"
    android:layout_height="200dp"
    android:layout_column="0"
    android:layout_row="0"
    android:background="@drawable/shape" >

    <ImageView
        android:id="@+id/myimage1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_column="0"
        android:layout_row="0"
        android:src="@drawable/ic_launcher" />
</LinearLayout>

<LinearLayout
    android:id="@+id/topright"
    android:layout_width="160dp"
    android:layout_height="200dp"
    android:layout_column="1"
    android:layout_row="0"
    android:background="@drawable/shape" >

    <ImageView
        android:id="@+id/myimage2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_column="0"
        android:layout_row="0"
        android:src="@drawable/ic_launcher" />
</LinearLayout>

<LinearLayout
    android:id="@+id/bottomleft"
    android:layout_width="160dp"
    android:layout_height="200dp"
    android:layout_column="0"
    android:layout_row="1"
    android:background="@drawable/shape" >

    <ImageView
        android:id="@+id/myimage3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />
</LinearLayout>

<LinearLayout
    android:id="@+id/bottomright"
    android:layout_width="160dp"
    android:layout_height="200dp"
    android:layout_column="1"
    android:layout_row="1"
    android:background="@drawable/shape" >

    <ImageView
        android:id="@+id/myimage4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_column="0"
        android:layout_row="0"
        android:src="@drawable/ic_launcher" />
</LinearLayout>

</GridLayout> 

and the Drag_and_Drop_App.java:

package com.example.awesomefilebuilderwidget;

import android.app.Activity;
import android.content.ClipData;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.LinearLayout;

public class Drag_and_Drop_App extends Activity {
/** Called when the activity is first created. */

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.drag_and_drop_app);
findViewById(R.id.myimage1).setOnTouchListener(new MyTouchListener());
findViewById(R.id.myimage2).setOnTouchListener(new MyTouchListener());
findViewById(R.id.myimage3).setOnTouchListener(new MyTouchListener());
findViewById(R.id.myimage4).setOnTouchListener(new MyTouchListener());
findViewById(R.id.topleft).setOnDragListener(new MyDragListener());
findViewById(R.id.topright).setOnDragListener(new MyDragListener());
findViewById(R.id.bottomleft).setOnDragListener(new MyDragListener());
findViewById(R.id.bottomright).setOnDragListener(new MyDragListener());

}

private final class MyTouchListener implements OnTouchListener {
 public boolean onTouch(View view, MotionEvent motionEvent) {
  if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
    ClipData data = ClipData.newPlainText("", "");
    DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
    view.startDrag(data, shadowBuilder, view, 0);
    view.setVisibility(View.INVISIBLE);
    return true;
  } else {
    return false;
  }
  }
 }

class MyDragListener implements OnDragListener {
Drawable enterShape = getResources().getDrawable(R.drawable.shape_droptarget);
Drawable normalShape = getResources().getDrawable(R.drawable.shape);

@Override
public boolean onDrag(View v, DragEvent event) {
  int action = event.getAction();
  switch (event.getAction()) {
  case DragEvent.ACTION_DRAG_STARTED:
    // do nothing
    break;
  case DragEvent.ACTION_DRAG_ENTERED:
    v.setBackgroundDrawable(enterShape);
    break;
  case DragEvent.ACTION_DRAG_EXITED:
    v.setBackgroundDrawable(normalShape);
    break;
  case DragEvent.ACTION_DROP:
    // Dropped, reassign View to ViewGroup
    View view = (View) event.getLocalState();
    ViewGroup owner = (ViewGroup) view.getParent();
    owner.removeView(view);
    LinearLayout container = (LinearLayout) v;
    container.addView(view);
    view.setVisibility(View.VISIBLE);
    break;
  case DragEvent.ACTION_DRAG_ENDED:
    v.setBackgroundDrawable(normalShape);
  default:
    break;
  }
  return true;
}
}
} 

Answer 1

I just changed the line:

<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"

to

<android.support.v7.widget.GridLayout xmlns:android="http://schemas.android.com/apk/res/android"

with the corresponding ending tag!