备份和还原数据库Android Studio [英] Backup and Restore Database android studio

问题描述

我想为我的应用程序中的数据库进行备份和还原，以便用户删除应用程序并再次重新安装时，他们可以恢复其数据. 在Android Studio中执行此操作的最佳方法是什么?

I want to make backup and restore for the database in my app, so that when the users delete the application and reinstall it again they can recover their data. What is the best way to do that in Android Studio?

推荐答案

备份和还原到您的数据库文件中可以使用多种类型，例如Google驱动器，放置框和一个驱动器.如果要从本地存储进行备份，请尝试以下给定的代码.

There are several types available in back up and restore to your db file like Google drive, drop box and one drive. if you want to do the back up from your local storage try below given code.

备份代码:

  public void backUp() {
    try {
        File sd = Environment.getExternalStorageDirectory();
        File data = Environment.getDataDirectory();

        if (sd.canWrite()) {
            String currentDBPath = "//data//your package     name//databases//dbname.db";
            String backupDBPath = "dbname.db";

            File currentDB = new File(data, currentDBPath);
            File backupDB = new File(sd, backupDBPath);

            Log.d("backupDB path", "" + backupDB.getAbsolutePath());

            if (currentDB.exists()) {
                FileChannel src = new     FileInputStream(currentDB).getChannel();
                FileChannel dst = new FileOutputStream(backupDB).getChannel();
                dst.transferFrom(src, 0, src.size());
                src.close();
                dst.close();
                Toast.makeText(getApplicationContext(), "Backup is successful to SD card", Toast.LENGTH_SHORT).show();
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

还原代码:

  public void restore() {
    try {
        File sd = Environment.getExternalStorageDirectory();
        File data = Environment.getDataDirectory();

        if (sd.canWrite()) {
            String currentDBPath = "//data//your package name//databases//dbname.db";;
            String backupDBPath = "dbname.db";
            File currentDB = new File(data, currentDBPath);
            File backupDB = new File(sd, backupDBPath);

            if (currentDB.exists()) {
                FileChannel src = new FileInputStream(backupDB).getChannel();
                FileChannel dst = new FileOutputStream(currentDB).getChannel();
                dst.transferFrom(src, 0, src.size());
                src.close();
                dst.close();
                Toast.makeText(getApplicationContext(), "Database Restored successfully", Toast.LENGTH_SHORT).show();
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

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