protected void Save_Click(){
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Author author = new Author();
                author.setId_author(Integer.parseInt(txtID.getText() + ""));
                author.setName(txtName.getText() + "");
                author.setAddress(txtAddress.getText() + "");
                author.setEmail(txtEmail.getText() + "");
                if (myDB_helper.insertAuthor(author) > 0){
                    Toast.makeText(getApplicationContext(), "Đã lưu thành công", Toast.LENGTH_LONG).show();
                }else
                    Toast.makeText(getApplicationContext(), "Lưu không thành công", Toast.LENGTH_LONG).show();
                txtID.setText("");
                txtName.setText("");
                txtAddress.setText("");
                txtEmail.setText("");
            }
        });
    }