如何从Google Drive导出和导入文件？

Question

I'm using Intent to export my .db file to the google drive. and import the .db file through the local folder on the device.

1. how can i import the file to my device from drive again?
2. what is the best way to "backup" the .db file and import the file?
3. it's possible to do that action without using "google drive api"?

Help me please !

 public class BackUpDb {

        Context context;

        public BackUpDb(Context activity) {
            this.context = activity;
            }

        public void exportDb(){
            File direct = new File(Environment
                    .getExternalStorageDirectory()
                    + "/folderToBeCreated");
            if (!direct.exists()) {
                if (direct.mkdir()) {
                    // directory is created;
                }
            }
            try {
                exportDB();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }


    public void importDb(){
         importDB();
    }



    // importing database
    @SuppressLint("SdCardPath")
    private void importDB() {
        try {
    //      File file = getBaseContext().getFileStreamPath(Environment.getExternalStorageDirectory()
    //              + "/MyDatabase");
    //      if(file.exists()){

                FileInputStream fis = new FileInputStream(Environment.getExternalStorageDirectory()
                        + "/folderToBeCreated/MyDatabase");       

                String outFileName = "/data/data/com.example.application/databases/"+DbHandler.DB_NAME;

                OutputStream output = new FileOutputStream(outFileName);
                byte[] buffer = new byte[1024];
                int length;
                while ((length = fis.read(buffer)) > 0) {
                    output.write(buffer, 0, length);
                }
                // Close the streams
                output.flush();
                output.close();
                fis.close();
                Toast.makeText(context, "Ok :)",Toast.LENGTH_LONG).show();




        } catch (Exception e) {
            Toast.makeText(context, "No list found",
                    Toast.LENGTH_LONG).show();
            e.printStackTrace();
        }
    }


    @SuppressLint("SdCardPath")
    private void exportDB() throws IOException {
        // Open your local db as the input stream
        try {
            String inFileName = "/data/data/com.example.application/databases/"+DbHandler.DB_NAME;
            File dbFile = new File(inFileName);
            FileInputStream fis = new FileInputStream(dbFile);

          String outFileName = Environment.getExternalStorageDirectory()+ "/folderToBeCreated/MyDatabase";


            // Open the empty db as the output stream
            OutputStream output = new FileOutputStream(outFileName);
            // transfer bytes from the inputfile to the outputfile
            byte[] buffer = new byte[1024];
            int length;
            while ((length = fis.read(buffer)) > 0) {
                output.write(buffer, 0, length);
            }
            // Close the streams
            output.flush();
            output.close();
            fis.close();







        } catch (Exception e) {
            Toast.makeText(context, e.toString(), Toast.LENGTH_LONG)
                    .show();
        }
        Toast.makeText(context,
                "save to :\n/folderToBeCreated",Toast.LENGTH_LONG).show();


    }


    public void sendDb(String mailAddres){

        Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType("application/octet-stream");
        intent.putExtra(Intent.EXTRA_EMAIL, new String[] {mailAddres});
        intent.putExtra(Intent.EXTRA_SUBJECT, "MyDatabase");

        File root = Environment.getExternalStorageDirectory();
        File file = new File(root, "/folderToBeCreated/MyDatabase");
        if (!file.exists() || !file.canRead()) {
            Toast.makeText(context, "No sd-card", Toast.LENGTH_SHORT).show();
            return;
        }
        Uri uri = Uri.parse("file://" + file.getAbsolutePath());
        intent.putExtra(Intent.EXTRA_STREAM, uri);
        context.startActivity(Intent.createChooser(intent, "BACKUP"));
    }



    }

Answer 1

从Android 4.4（KitKat）开始，已删除了在外部SD卡上创建文件的功能。