File transfer from Assets folder to Phone Storage with AsyncTask

Add below permission to AndroidManifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

MainActivity.java

import java.io.File;
	import java.util.ArrayList;
	import android.os.Bundle;
	import android.os.Environment;
	import android.app.Activity;
	import android.view.Menu;
	import android.widget.Toast;
	public class MainActivity extends Activity {
	// this where your file will be stored in sdcard in this case in folder (YOUR_FILE)
	static String BASE_FILE = Environment.getExternalStorageDirectory()+"/YOUR_FILE/";
	ArrayList<String> TmpList = new ArrayList<String>();
	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	// create dynamic array to add your files
	ArrayList<String> MyFiles = new ArrayList<String>();
	MyFiles.add("demo_voice.mp3");
	MyFiles.add("demo_img.jpg");
	// add your files here
	// create base folder if not exists
	File f = new File(BASE_FILE);
	if(!f.exists())
	f.mkdir();
	// this loop to check if files already coped or not or any file delete
	for(int i=0;i<MyFiles.size();i++){
	File check = new File(BASE_FILE,MyFiles.get(i));
	if(!check.exists())
	TmpList.add(MyFiles.get(i)); // copy not coped items to other list
	}
	// now check if not all files copy or something remove
	if(TmpList.size()>0)
	new AsyncCopy(this, BASE_FILE, TmpList).execute("");
	else
	Toast.makeText(getApplicationContext(), "all files coped ",Toast.LENGTH_LONG).show();
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
	// Inflate the menu; this adds items to the action bar if it is present.
	getMenuInflater().inflate(R.menu.main, menu);
	return true;
	}
	} AsyncCopy.java import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.util.ArrayList; import android.app.Activity; import android.app.ProgressDialog; import android.os.AsyncTask; import android.widget.Toast; public class AsyncCopy extends AsyncTask<String, String, String>{ String savePath; Activity ctx; private ProgressDialog pDialog; ArrayList<String> arr; AsyncCopy(Activity _ctx,String _savePath,ArrayList<String> Files){ this.ctx = _ctx; this.savePath = _savePath; this.arr = Files; } @Override protected void onPreExecute() { pDialog = new ProgressDialog(ctx); pDialog.setMessage("Copying files from asset to sdcard"); pDialog.setIndeterminate(true); pDialog.setCancelable(false); pDialog.show(); super.onPreExecute(); } @Override protected String doInBackground(String... urls) { File f = new File(savePath); if(!f.exists()) f.mkdir(); for(int i=0;i<arr.size();i++) Copy(arr.get(i)); return null; } @Override protected void onPostExecute(String unused) { Toast.makeText(ctx,"Copy Done",Toast.LENGTH_LONG).show(); pDialog.hide(); } void Copy(String fname){ try{ int count; InputStream input= ctx.getAssets().open(fname); OutputStream output = new FileOutputStream(savePath+"/"+fname); byte data[] = new byte[1024]; while ((count = input.read(data))>0) { output.write(data, 0, count); } output.flush(); output.close(); input.close(); }catch(Exception e){ // error while copying } } }