package com.tware.pdfdrop;import java.io.File;import android.app.Activity;import android.graphics.Color;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.TextView;public class PdfDropActivity extends Activity{    /** Called when the activity is first created. */    TextView textview;        @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);         textview = (TextView)findViewById(R.id.v_file_list);        View clsbtn = findViewById(R.id.btn_clean);        clsbtn.setOnClickListener(new OnClickListener(){            public void onClick(View v)            {                   File f = new File("/sdcard");                                      File[] fl = f.listFiles();                   for (int i=0; i