Android Rename Move Copy file in SD Card (Java Android)

package com.myapp;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // button1 (Rename)
        final Button btn1 = (Button) findViewById(R.id.button1);
        // button2 (Copy)
        final Button btn2 = (Button) findViewById(R.id.button2);
        // button2 (Move)
        final Button btn3 = (Button) findViewById(R.id.button3);
        
        // Perform action on click (Rename)
        btn1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
            	
        		/*** Rename file in SD Card ***/
				try {
					
						String OldName = "/mnt/sdcard/mydata/myfile.txt";
						String NewName = "/mnt/sdcard/mydata/myNewfile.txt";
						File file = new File(OldName);
						file.renameTo(new File(NewName));
						
						file = null;
					
			 		   	Toast.makeText(MainActivity.this, "File Rename!",
					 		     Toast.LENGTH_LONG).show();   
			 		   
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
			 		   Toast.makeText(MainActivity.this, "Failed! = " + e.getMessage() ,
					 		     Toast.LENGTH_LONG).show();   
				}
           

            }
        });
        
        
        // Perform action on click (Copy)
        btn2.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
            	
	    		/*** Copy file in SD Card ***/
				try {
						
						File SourceName = new File("/mnt/sdcard/mydata/myfile.txt");
						File DestName = new File("/mnt/sdcard/mypicture/myfile.txt");
						
						copyFile(SourceName,DestName);
					
			 		   	Toast.makeText(MainActivity.this, "File Copy!",
					 		     Toast.LENGTH_LONG).show();   
			 		   
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
			 		   Toast.makeText(MainActivity.this, "Failed! = " + e.getMessage() ,
					 		     Toast.LENGTH_LONG).show();   
				}
           

            }
        });
        
        // Perform action on click (Move)
        btn3.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
            	
	    		/*** Move file in SD Card ***/
				try {
						
						File SourceName = new File("/mnt/sdcard/mydata/myfile.txt");
						File DestName = new File("/mnt/sdcard/mypicture/myfile.txt");
						copyFile(SourceName,DestName); // Copy
						SourceName.delete(); // Delete
					
			 		   	Toast.makeText(MainActivity.this, "File Move!",
					 		     Toast.LENGTH_LONG).show();   
			 		   
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
			 		   Toast.makeText(MainActivity.this, "Failed! = " + e.getMessage() ,
					 		     Toast.LENGTH_LONG).show();   
				}
           

            }
        });
        
        
    }
    

    
    public static void copyFile(File sourceFile, File destFile) throws IOException {
        if(!destFile.exists()) {
            destFile.createNewFile();
        }

        FileChannel source = null;
        FileChannel destination = null;
        try {
            source = new FileInputStream(sourceFile).getChannel();
            destination = new FileOutputStream(destFile).getChannel();

            long count = 0;
            long size = source.size();              
            while((count += destination.transferFrom(source, count, size-count))<size);
        }
        finally {
            if(source != null) {
                source.close();
            }
            if(destination != null) {
                destination.close();
            }
        }
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
	
}