Preserving Value When Orientation Changes

I am developing a very basic Android App that adds a number in TextView whenever I hit the Button. The digit showing in TextView is also preserved when the orientation of the Mobile changes using the onSaveInstanceState() and onRestoreInstanceState() functions.

The problem is when orientation changes the value is preserved but when the Button is pressed once again after the changing of the orientation it again starts the counting from 0 rather then starting it from the preserved value.

My code:

public class MainActivity extends AppCompatActivity {

    TextView showValue;
    int counter=0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        showValue = (TextView) findViewById(R.id.CounterValue);
    }


    public void countIN(View view)
    {
        counter++;
        showValue.setText(Integer.toString(counter));
    }


    @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putString("my_text", showValue.getText().toString());
        super.onSaveInstanceState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        showValue.setText(savedInstanceState.getString("my_text"));
    }
 }

Thank You for your response.

add

counter=Integer.parseInt(savedInstanceState.getString("my_text"));

inside onRestoreInstanceState method

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    showValue.setText(savedInstanceState.getString("my_text"));
    counter=Integer.parseInt(savedInstanceState.getString("my_text"));
}