Listing Files from SDCard in Android Example

First Add permission for external storage in Manifest.xml file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.rajeshvijayakumar.fldemo"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="org.rajeshvijayakumar.fldemo.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

flist.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ListView
        android:id="@+id/listView1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

</RelativeLayout>

fl_list_item.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <TextView
        android:id="@+id/fname"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</RelativeLayout>

MainActivity.java

package org.rajeshvijayakumar.fldemo;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity implements OnItemLongClickListener {

    private ListView mListView;
    private List<String> fileNameList;
    private FlAdapter mAdapter;
    private File file;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.flist);
        mListView = (ListView) findViewById(R.id.listView1);
        file = Environment.getExternalStorageDirectory();
        fileNameList = getFileListfromSDCard();
        mAdapter = new FlAdapter(this, R.layout.fl_list_item, fileNameList);
        mListView.setAdapter(mAdapter);
    }

    private List<String> getFileListfromSDCard() {
        String state = Environment.getExternalStorageState();
        List<String> flLst = new ArrayList<String>();
        if (Environment.MEDIA_MOUNTED.equals(state) && file.isDirectory()) {
            File[] fileArr = file.listFiles();
            int length = fileArr.length;
            for (int i = 0; i < length; i++) {
                File f = fileArr[i];
                flLst.add(f.getName());
            }
        }

        return flLst;
    }

    public class FlAdapter extends ArrayAdapter<String> {

        private List<String> fLst;
        private Context adapContext;

        public FlAdapter(Context context, int textViewResourceId,
                List<String> fLst) {
            super(context, textViewResourceId, fLst);
            this.fLst = fLst;
            adapContext = context;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            View view = convertView;
            FHolder fHolder = null;

            if (convertView == null) {
                view = View.inflate(adapContext, R.layout.fl_list_item, null);

                fHolder = new FHolder();
                fHolder.fNameView = (TextView) view.findViewById(R.id.fname);

                view.setTag(fHolder);
            } else {
                fHolder = (FHolder) view.getTag();
            }
            String fileName = fLst.get(position);
            fHolder.fNameView.setText(fileName);

            return view;
        }
    }

    static class FHolder {
        public TextView fNameView;
    }
}

Output :

  

Source : Coming Soon to Github.............