代碼

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity" ><Buttonandroid:id="@+id/btnScanSD"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentTop="true"android:layout_alignRight="@+id/btnReadFromDB"android:text="掃描SD卡中音樂文件" /><ListViewandroid:id="@+id/myList"android:layout_width="match_parent"android:layout_height="300dp"android:layout_alignParentLeft="true"android:layout_alignParentBottom="true"></ListView><Buttonandroid:id="@+id/btnReadFromDB"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_below="@+id/btnScanSD"android:layout_centerHorizontal="true"android:layout_marginTop="32dp"android:text="數據庫讀取音樂文件" /></RelativeLayout>

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical" ><TextView android:id="@+id/txt_music_name"android:layout_width="match_parent"android:layout_height="50dp"android:singleLine="true"android:gravity="center_vertical"android:ellipsize="marquee"/></LinearLayout>

MainActivity.java

package com.progressbartest;import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.provider.MediaStore;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.ClipData.Item;
import android.database.Cursor;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;public class MainActivity extends Activity {//掃描路徑private static String filePath = Environment.getExternalStorageDirectory()+File.separator;//絕對路徑private static String nowPath = "";private static String str = "";//掃描文件列表private static List<String> mList = new ArrayList<String>();private SimpleAdapter adapter;private List<Map<String,Object>> items = new ArrayList<Map<String,Object>>();//定義進度對話框標識——掃描SD卡音樂文件final int PROGRESS_DIALOG = 0X112;//定義進度對話框標識——掃描數據庫音樂文件final int PROGRESS_DB = 0X111;private ProgressDialog pd;private Handler handler;private ListView myList;//當前所點擊按鈕標識  0-掃描SD卡 1-讀取數據庫private int mClickBtn = -1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//掃描SD卡音樂文件Button btnScanSD = (Button)findViewById(R.id.btnScanSD);//讀取數據庫音樂文件Button btnReadFromDB = (Button)findViewById(R.id.btnReadFromDB);myList = (ListView)findViewById(R.id.myList);btnScanSD.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubshowDialog(PROGRESS_DIALOG);}});btnReadFromDB.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View v) {// TODO Auto-generated method stubshowDialog(PROGRESS_DB);}});handler = new Handler(){public void handleMessage(Message msg){if(msg.arg1 == 1){String ss = nowPath;if(nowPath.length() > 25){ss = "..." + nowPath.substring(nowPath.length() - 22);}pd.setMessage(ss);}else if(msg.arg1 == 2){pd.dismiss();DisplayToast("掃描完畢");if(items.size()>0){items.clear();adapter.notifyDataSetChanged();}for(int i = 0; i < mList.size(); i++){Map<String,Object> item = new HashMap<String,Object>();item.put("musicName", mList.get(i).toString());//sss = mList.get(i).toString();items.add(item);}adapter = new SimpleAdapter(MainActivity.this,items,R.layout.list_item,new String[]{"musicName"},new int[]{R.id.txt_music_name});myList.setAdapter(adapter);//DisplayToast(sss);}}};}@Overridepublic Dialog onCreateDialog(int id, Bundle status){switch(id){case PROGRESS_DIALOG:pd = new ProgressDialog(this);pd.setMax(100);pd.setMessage("正在掃描，請稍后...");pd.setCancelable(false);pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);pd.setIndeterminate(false);break;case PROGRESS_DB:pd = new ProgressDialog(this);pd.setMax(100);pd.setMessage("正在掃描，請稍后...");pd.setCancelable(false);pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);pd.setIndeterminate(false);break;}return pd;}//該方法在onCreateDialog方法調用之后被回調@Overridepublic void onPrepareDialog(int id, Dialog dialog){super.onPrepareDialog(id, dialog);switch(id){case PROGRESS_DIALOG://創建新線程來執行較長時間的任務new Thread(){@Overridepublic void run(){//執行任務getScanFile(filePath);//發送執行完成消息Message message = new Message();//任務完成標志message.arg1 = 2;handler.sendMessage(message);}}.start();break;case PROGRESS_DB:new Thread(){@Overridepublic void run(){//執行任務getFromDB();//發送執行完成消息Message message = new Message();//任務完成標志message.arg1 = 2;handler.sendMessage(message);}}.start();break;}}private void getScanFile(String path){//清空列表//mList.clear();File file = new File(path);//獲取該路徑下的文件及文件夾File[] files = file.listFiles();//判斷該路徑下是否存在文件或文件夾if(files != null){//循環判斷for(int i = 0; i < files.length; i++){nowPath = files[i].getAbsolutePath();Message msg = new Message();msg.arg1 = 1;handler.sendMessage(msg);//判斷是否是文件夾if(files[i].isDirectory()){getScanFile(files[i].getAbsolutePath());}else{//判斷文件的擴展名if(files[i].getAbsolutePath().endsWith(".mp3")){//str += files[i].getName() + "\n";mList.add(files[i].getName());}}}}}/** 獲取音樂列表*/private void getFromDB(){mList.clear();//清除所有歌曲信息Cursor cur = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, new String[]{MediaStore.Audio.Media._ID,MediaStore.Audio.Media.DISPLAY_NAME,MediaStore.Audio.Media.TITLE,MediaStore.Audio.Media.DURATION,MediaStore.Audio.Media.ARTIST,MediaStore.Audio.Media.ALBUM,MediaStore.Audio.Media.YEAR,MediaStore.Audio.Media.MIME_TYPE,MediaStore.Audio.Media.SIZE,MediaStore.Audio.Media.DATA}, null, null, null);while(cur.moveToNext()){mList.add(cur.getString(1));}cur.close();}private void DisplayToast(String s){Toast.makeText(this, s, Toast.LENGTH_SHORT).show();}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.activity_main, menu);return true;}}

源碼下載地址： http://download.csdn.net/detail/wangzhongshun/6316687