android编程实现sd卡读取数据库的方法

本文实例讲述了android编程实现sd卡读取数据库的方法。分享给大家供大家参考，具体如下：

先在 Manifest 里添加权限：

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

然后在 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";
// 初始化数据库
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;
}

希望本文所述对大家Android程序设计有所帮助。