Converting a sensor value using simple arithmetic - sensors

Question

I am currently working on a light sensor. I managed to make the sensor work. But I want to change the value of the sensor being shown by multiplying it with 0.002 with a press of a button. I can't seem to get the code of the button to multiply because it keeps saying operator (*) cannot be applied to java.lang.String, double. I have tried the double.parse but can't seems to get to work. Here is my code:
public class MainActivity extends AppCompatActivity implements SensorEventListener {
TextView textView;
SensorManager sensorManager;
Sensor sensor;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.textView);
sensorManager = (SensorManager) getSystemService(Service.SENSOR_SERVICE);
sensor = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
Button button = (Button) findViewById(R.id.button3);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View multiply) {
textView.setText(Integer.parseInt(textView.getText().toString()*0.002));
}
});
}
#Override
protected void onPause() {
super.onPause();
sensorManager.unregisterListener(this);
}
#Override
protected void onResume() {
super.onResume();
sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);
}
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
if (sensorEvent.sensor.getType() == Sensor.TYPE_LIGHT) {
textView.setText("" + sensorEvent.values[0]);
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int i) {
}