備份和恢復數據庫android studio

Question

我想爲我的應用程序中的數據庫進行備份和恢復，以便當用戶刪除應用程序並重新安裝時，他們可以恢復他們的數據。 在Android Studio中執行此操作的最佳方法是什麼？

Answer 1

有幾種類型的備份和恢復到您的數據庫文件，如谷歌驅動器，下拉框和一個驅動器。如果您想從本地存儲中進行備份，請嘗試下面的代碼。

備份代碼：

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(); 
    } 
} 

還原代碼：

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(); 
    } 
}