早期很多android设备并未配置陀螺仪,所以无法调用SensorManager的Sensor.TYPE_STEP_COUNTER的Sensor,试了很多算法,发现这个算法最好,
下面是SensorEventListener的实现,更多细节参阅https://github.com/bagilevi/android-pedometer

package name.bagi.levente.pedometer;
import java.util.ArrayList;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.Log;
/**
* Detects steps and notifies all listeners (that implement StepListener).
* @author Levente Bagi
* @todo REFACTOR: SensorListener is deprecated
*/
public class StepDetector implements SensorEventListener
{
private final static String TAG = "StepDetector";
private float mLimit = 10;
private float mLastValues[] = new float[3*2];
private float mScale[] = new float[2];
private float mYOffset;
private float mLastDirections[] = new float[3*2];
private float mLastExtremes[][] = { new float[3*2], new float[3*2] };
private float mLastDiff[] = new float[3*2];
private int mLastMatch = -1;
private ArrayList<StepListener> mStepListeners = new ArrayList<StepListener>();
public StepDetector() {
int h = 480; // TODO: remove this constant
mYOffset = h * 0.5f;
mScale[0] = - (h * 0.5f * (1.0f / (SensorManager.STANDARD_GRAVITY * 2)));
mScale[1] = - (h * 0.5f * (1.0f / (SensorManager.MAGNETIC_FIELD_EARTH_MAX)));
}
public void setSensitivity(float sensitivity) {
mLimit = sensitivity; // 1.97 2.96 4.44 6.66 10.00 15.00 22.50 33.75 50.62
}
public void addStepListener(StepListener sl) {
mStepListeners.add(sl);
}
//public void onSensorChanged(int sensor, float[] values) {
public void onSensorChanged(SensorEvent event) {
Sensor sensor = event.sensor;
synchronized (this) {
if (sensor.getType() == Sensor.TYPE_ORIENTATION) {
}
else {
int j = (sensor.getType() == Sensor.TYPE_ACCELEROMETER) ? 1 : 0;
if (j == 1) {
float vSum = 0;
for (int i=0 ; i<3 ; i++) {
final float v = mYOffset + event.values[i] * mScale[j];
vSum += v;
}
int k = 0;
float v = vSum / 3;
float direction = (v > mLastValues[k] ? 1 : (v < mLastValues[k] ? -1 : 0));
if (direction == - mLastDirections[k]) {
// Direction changed
int extType = (direction > 0 ? 0 : 1); // minumum or maximum?
mLastExtremes[extType][k] = mLastValues[k];
float diff = Math.abs(mLastExtremes[extType][k] - mLastExtremes[1 - extType][k]);
if (diff > mLimit) {
boolean isAlmostAsLargeAsPrevious = diff > (mLastDiff[k]*2/3);
boolean isPreviousLargeEnough = mLastDiff[k] > (diff/3);
boolean isNotContra = (mLastMatch != 1 - extType);
if (isAlmostAsLargeAsPrevious && isPreviousLargeEnough && isNotContra) {
Log.i(TAG, "step");
for (StepListener stepListener : mStepListeners) {
stepListener.onStep();
}
mLastMatch = extType;
}
else {
mLastMatch = -1;
}
}
mLastDiff[k] = diff;
}
mLastDirections[k] = direction;
mLastValues[k] = v;
}
}
}
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
}