protected void Select_Click(){
        btnSelect.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ArrayList<Author> list_author = new ArrayList<>();
                ArrayList<String> list_string = new ArrayList<>();
                if (txtID.getText().toString().equals("")){
                    list_author = myDB_helper.getAllAuthor();
                }
                else {
                    list_author = myDB_helper.getAuthor(Integer.parseInt(txtID.getText().toString()));
                }
                if (list_author.size() > 0){
                    for (Author author : list_author){
                        list_string.add(author.getId_author() + "");
                        list_string.add(author.getName());
                        list_string.add(author.getAddress());
                        list_string.add(author.getEmail());
                    }
                    ArrayAdapter<String> adapter = new ArrayAdapter<String>(AuthorActivity.this, android.R.layout.simple_list_item_1, list_string);
                    dv_display.setAdapter(adapter);
                }else {
                    Toast.makeText(getApplicationContext(), "Cơ sở dữ liệu rỗng", Toast.LENGTH_LONG).show();
                }
            }
        });
    }