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BOOK: Professional Android Application Development ISBN: 978-0-470-34471-2
This is the forum to discuss the Wrox book Professional Android Application Development by Reto Meier; ISBN: 9780470344712
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Old April 16th, 2009, 02:42 PM
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Thumbs up Chapter 7 Speedometer SensorSimulator

Hi Reto Meier

Excellent book!

We're using the accelerometer simulator for a proyect:


The speedometer code compile fine,but the connection from the code to displaying
the updateGUI() is not working.

In the openintents code they use:

first disable the current sensor
The View mGraphView can not be resolved??

package com.paad.speedometer;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import org.openintents.hardware.SensorManagerSimulator;
import org.openintents.provider.Hardware;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.hardware.SensorListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.TextView;
public class Speedometer extends Activity {
Handler handler = new Handler();
SensorManager sensorManager;
TextView myTextView;
float appliedAcceleration = 0;
float currentAcceleration = 0;
float velocity = 0;
Date lastUpdate;
View view;
public void onCreate(Bundle icicle) {

myTextView = (TextView)findViewById(R.id.myTextView);
lastUpdate = new Date(System.currentTimeMillis());
sensorManager = (SensorManager)new SensorManagerSimulator((SensorManager)getSystemSer vice(Context.SENSOR_SERVICE));
// Intent intent = new Intent(Intent.ACTION_VIEW, Hardware.Preferences.CONTENT_URI); startActivity(intent);
sensorManager.registerListener(sensorListener, SensorManager.SENSOR_ACCELEROMETER, SensorManager.SENSOR_DELAY_FASTEST);
Timer updateTimer = new Timer("velocityUpdate");
updateTimer.scheduleAtFixedRate(new TimerTask() {
public void run() {
}, 0, 1000);
private void updateGUI() {
// Convert from meters per second to miles per hour.
final double mph = (Math.round(100*velocity / 1.6 * 3.6))/100;
// Update the GUI
handler.post(new Runnable() {
public void run() {
myTextView.setText(String.valueOf(mph) + "mph");
private void updateVelocity() {
// Calculate how long this acceleration has been applied.
Date timeNow = new Date(System.currentTimeMillis());
long timeDelta = timeNow.getTime()-lastUpdate.getTime();
// Calculate the change in velocity at the
// current acceleration since the last update.
float deltaVelocity = appliedAcceleration * (timeDelta/1000);
appliedAcceleration = currentAcceleration;
// Add the velocity change to the current velocity.
velocity += deltaVelocity;
private final SensorListener sensorListener = new SensorListener() {
double calibration = Double.NaN;

public void onSensorChanged(int sensor, float[] values) {
double x = values[SensorManager.DATA_X];
double y = values[SensorManager.DATA_Y];
double z = values[SensorManager.DATA_Z];

double a = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2) + Math.pow(z, 2));

if (calibration == Double.NaN)
calibration = a;
else {
currentAcceleration = (float)a;
public void onAccuracyChanged(int sensor, int accuracy) {}
The enulator displays 0.0 mph

And sometimes(after 30 minutes) display the speed.

120 mph

How you pass the the simulator sensor values to the original sensor values?
The simulator works fine,look like it is not updated to this SDK 1.0????

Last edited by JHandal; April 17th, 2009 at 04:19 PM..

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