Android 从外部存储导入数据库

Question

我正在尝试从外部驱动器 (USB) 导入数据库文件，以恢复备份数据。文件存在且路径正确，但没有导入数据库，这是我的代码：

File usb = new File("/storage/UsbDriveA/BackupHM/database.db");
File currentDB = getDatabasePath("database.db");

FileChannel source = null;
FileChannel destination = null;
String backupDBPath = "/storage/UsbDriveA/BackupHM/database.db";
File backupDB = new File(usb, backupDBPath);
                        try {
                            source = new FileInputStream(backupDB).getChannel();
                            destination = new FileOutputStream(currentDB).getChannel();
                            destination.transferFrom(source, 0, source.size());
                            source.close();
                            destination.close();
                            Toast toast1 = Toast.makeText(getApplicationContext(), ("Restore ok"), Toast.LENGTH_SHORT);
                            toast1.show();
                            finish();
                        } catch (IOException e) {
                            e.printStackTrace();
                            Toast toast = Toast.makeText(getApplicationContext(), ("Error!"), Toast.LENGTH_LONG);
                            toast.show();
                        }
                    }

Answer 1

编码错误。将声明块更改为：

        //File usb = new File("/storage/UsbDriveA/BackupHM/database.db");
        File currentDB = getDatabasePath("database.db");

        FileChannel source = null;
        FileChannel destination = null;
        String backupDBPath = "/storage/UsbDriveA/BackupHM/database.db";
        File backupDB = new File(backupDBPath);