Drag And Drop Example is Not working in Android

import android.app.Activity;
import android.content.ClipData;
import android.content.ClipDescription;
import android.os.Bundle;
import android.util.Log;
import android.view.DragEvent;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class MainActivity extends Activity {

	ImageView ima;
	private static final String IMAGEVIEW_TAG = "Android Logo";
	String msg;

	private android.widget.RelativeLayout.LayoutParams layoutParams;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		ima=(ImageView)findViewById(R.id.iv_logo);
		
		//Sets the tag
		
		ima.setTag(IMAGEVIEW_TAG);
		
		ima.setOnLongClickListener(new View.OnLongClickListener() {
			
			@Override
			public boolean onLongClick(View v) {
				// TODO Auto-generated method stub
				
				ClipData.Item item=new ClipData.Item((CharSequence) v.getTag());
				
				String[] mymeTypes={ClipDescription.MIMETYPE_TEXT_PLAIN};
				ClipData dragData=new ClipData(v.getTag().toString(), mymeTypes, item);
				
				//Instatiate the drag Shadow Builder
				
				View.DragShadowBuilder myShadow=new DragShadowBuilder(ima);
				
				//Starts the Drag
				
				v.startDrag(dragData, //The data to be dragged 
						myShadow, //the dragShoadow Builder
						null,
						0 //Flags not currently used set to 0
						);
				return true;
			}
		});
		
		//Create and set the drag event listener for the View
		
		ima.setOnDragListener(new OnDragListener(){
			@Override
			public boolean onDrag(View v, DragEvent event) {
				// TODO Auto-generated method stub
				
				switch(event.getAction()){
				
				case DragEvent.ACTION_DRAG_STARTED:
					layoutParams=(RelativeLayout.LayoutParams)v.getLayoutParams();
					Log.d(msg,"Action is DragEvent.ACTION_DRAG_STARTED");
					
					//Do Nothing Break
					break;
					
				case DragEvent.ACTION_DRAG_ENTERED:
					Log.d(msg,"Action is DragEvent.ACTION_DRAG_ENTERED");
					int x_cord=(int)event.getX();
					int y_cord=(int)event.getY();
					break;
					
				case DragEvent.ACTION_DRAG_EXITED:
					Log.d(msg,"Action is DragEvent.ACTION_DRAG_EXITED");
					x_cord=(int)event.getX();
					y_cord=(int)event.getY();
					break;
					
				case DragEvent.ACTION_DRAG_LOCATION:
					Log.d(msg,"Action is DragEvent.ACTION_DRAG_LOCATION");
					x_cord=(int)event.getX();
					y_cord=(int)event.getY();
					break;
					
				case DragEvent.ACTION_DRAG_ENDED:
					Log.d(msg,"Action is DragEvent.ACTION_DRAG_ENDED");
					break;
					
				case DragEvent.ACTION_DROP:
					Log.d(msg,"Action is DragEvent.ACTION_DROP");
					break;
					
					default:
						break;
						
				
				}
				return true;
				
			}
		});
	}

}

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android">
    android:id="@+id/container"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/iv_logo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:contentDescription="@string/drag_drop"
        android:src="@drawable/ic_launcher">

</relativelayout>