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 Android教程網 >> Android技術 >> Android開發實例 >> 安卓開發中 sd卡讀取數據庫實例

安卓開發中 sd卡讀取數據庫實例

編輯:Android開發實例

  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;

  }

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