android編程實現sd卡讀取數據庫的方法

本文實例講述了android編程實現sd卡讀取數據庫的方法。分享給大家供大家參考，具體如下：

先在 Manifest 裡添加權限：

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

然後在 mainActivity 添加方法：

SQLiteDatabase db;
private final String DATABASE_PATH = android.os.Environment
 .getExternalStorageDirectory().getAbsolutePath() + "/vote";
private String DATABASE_FILENAME = "db_vote.db";
// 初始化數據庫
private SQLiteDatabase openDatabase() {
  try {
   String databaseFilename = DATABASE_PATH + "/" + DATABASE_FILENAME;
   File dir = new File(DATABASE_PATH);
   if (!dir.exists())
    dir.mkdir();
   if (!(new File(databaseFilename)).exists()) {
    InputStream is = getResources().openRawResource(R.raw.db_vote);
    FileOutputStream fos = new FileOutputStream(databaseFilename);
    byte[] buffer = new byte[8192];
    int count = 0;
    while ((count = is.read(buffer)) > 0) {
     fos.write(buffer, 0, count);
    }
    fos.close();
    is.close();
   }
   db = SQLiteDatabase.openOrCreateDatabase(databaseFilename, null);
   return db;
  } catch (Exception e) {
   e.printStackTrace();
  }
  return null;
}

希望本文所述對大家Android程序設計有所幫助。