ListView及系統音樂資料庫

1.UI檔的xml程式碼

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

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

</LinearLayout>

2.MainActivity.java程式碼

import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Toast;

public class MainActivity extends Activity {
ListView musiclist;
Cursor musiccursor;
int music_column_index;
int count;
MediaPlayer mMediaPlayer;

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

// 音樂檔案匯入時系統會在資料庫的Audio View上建立對應資料列
// 因此Android的對應類別就是MediaStore.Audio
// 透過Eclipse就可以找到下面幾個欄位資料
// MediaStore.Audio.Media._ID, MediaStore.Audio.Media.DATA
// MediaStore.Audio.Media.DISPLAY_NAME, MediaStore.Video.Media.SIZE
// MediaStore.Audio.Media.DATA是音樂檔案所在路徑位置
private void init_phone_music_grid() {
System.gc();
String[] proj = { MediaStore.Audio.Media._ID,
MediaStore.Audio.Media.DATA,
MediaStore.Audio.Media.DISPLAY_NAME,
MediaStore.Audio.Media.SIZE };
musiccursor = managedQuery(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
proj, null, null, null);
count = musiccursor.getCount();
musiclist = (ListView) findViewById(R.id.PhoneMusicList);
musiclist.setAdapter(new MusicAdapter(getApplicationContext()));
musiclist.setOnItemClickListener(musicgridlistener);
mMediaPlayer = new MediaPlayer();
}

private OnItemClickListener musicgridlistener = new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position,
long id) {
System.gc();
music_column_index = musiccursor
.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
musiccursor.moveToPosition(position);
String filename = musiccursor.getString(music_column_index);
try {
if (mMediaPlayer.isPlaying()) {
Toast.makeText(MainActivity.this, "Player Stoped",
2000).show();
mMediaPlayer.stop();
mMediaPlayer.reset();
return;
}
// 音樂檔案播放標準程序
mMediaPlayer.setDataSource(filename);
mMediaPlayer.prepare();
mMediaPlayer.start();
} catch (Exception e) {
}
}
};

public class MusicAdapter extends BaseAdapter {
private Context mContext;

public MusicAdapter(Context c) {
mContext = c;
}

public int getCount() {
return count;
}

public Object getItem(int position) {
return position;
}

public long getItemId(int position) {
return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
System.gc();
TextView tv1 = new TextView(mContext.getApplicationContext());
TextView tv2 = new TextView(mContext.getApplicationContext());
ImageView img = new ImageView(mContext.getApplicationContext());
// 設定圖片及上下文所需要的畫面元件
img.setImageResource(R.drawable.ic_launcher);
tv1.setTextSize(12.0f);
tv2.setTextSize(12.0f);
String id = null;

music_column_index = musiccursor
.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME);
musiccursor.moveToPosition(position);
id = musiccursor.getString(music_column_index);
tv1.setText(id);
music_column_index = musiccursor
.getColumnIndexOrThrow(MediaStore.Audio.Media.SIZE);
musiccursor.moveToPosition(position);
id = "Size(MB):"
+ String.format("%,5.2f", Double
.parseDouble(musiccursor
.getString(music_column_index)) / 1024);
tv2.setText(id);

// 產生兩個線性佈局物件第一個是水平方向佈局
// 左邊加入圖片右邊加入第二個線性佈局方向是垂直方向佈局
// 最後加入文字元件到第二個線性佈局內
LinearLayout layout = new LinearLayout(
mContext.getApplicationContext());
LinearLayout innerLayout = new LinearLayout(
mContext.getApplicationContext());
layout.setOrientation(LinearLayout.HORIZONTAL);
innerLayout.setOrientation(LinearLayout.VERTICAL);
innerLayout.addView(tv1);
innerLayout.addView(tv2);
layout.addView(img);
layout.addView(innerLayout);
return layout;
}
}
}