Android实现计步传感器功能

本文对原文：android实现计步功能初探，计步项目进行了精简，移除了进程服务和计时、守护进程、数据库保存等等，方便扩展功能。

本文源码：https://github.com/lifegh/StepOrient

Android4.4以上版本，有些手机有计步传感器可以直接使用，
而有些手机没有，但有加速度传感器，也可以实现计步功能(需要计算加速度波峰波谷来判断人走一步)！

一.调用

public class MainActivity extends AppCompatActivity implements StepSensorBase.StepCallBack{
  .........
  @Override
  public void Step(int stepNum) {
    // 计步回调
    stepText.setText("步数:" + stepNum);
  }

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);   
    setContentView(R.layout.activity_main);
    stepText = (TextView) findViewById(R.id.step_text);

    // 开启计步监听, 分为加速度传感器、或计步传感器
    stepSensor = new StepSensorPedometer(this, this);
    if (!stepSensor.registerStep()) {
      Toast.makeText(this, "计步传传感器不可用！", Toast.LENGTH_SHORT).show();
      stepSensor = new StepSensorAcceleration(this, this);
      if (!stepSensor.registerStep()) {
        Toast.makeText(this, "加速度传感器不可用！", Toast.LENGTH_SHORT).show();
      }
    }
  }
  .......
 }

 /**
 * 计步传感器抽象类，子类分为加速度传感器、或计步传感器
 */
public abstract class StepSensorBase implements SensorEventListener {
  private Context context;
  protected StepCallBack stepCallBack;
  protected SensorManager sensorManager;
  protected static int CURRENT_SETP = 0;
  protected boolean isAvailable = false;

  public StepSensorBase(Context context, StepCallBack stepCallBack) {
    this.context = context;
    this.stepCallBack = stepCallBack;
  }

  public interface StepCallBack {
    /**
     * 计步回调
     */
    void Step(int stepNum);
  }

  /**
   * 开启计步
   */
  public boolean registerStep() {
    if (sensorManager != null) {
      sensorManager.unregisterListener(this);
      sensorManager = null;
    }
    sensorManager = SensorUtil.getInstance().getSensorManager(context);
    registerStepListener();
    return isAvailable;
  }

  /**
   * 注册计步监听器
   */
  protected abstract void registerStepListener();

  /**
   * 注销计步监听器
   */
  public abstract void unregisterStep();
}

二.直接使用计步传感器实现计步

/**
 * 计步传感器
 */
public class StepSensorPedometer extends StepSensorBase {
  private final String TAG = "StepSensorPedometer";
  private int lastStep = -1;
  private int liveStep = 0;
  private int increment = 0;
  private int sensorMode = 0; // 计步传感器类型

  public StepSensorPedometer(Context context, StepCallBack stepCallBack) {
    super(context, stepCallBack);
  }

  @Override
  protected void registerStepListener() {
    Sensor detectorSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_DETECTOR);
    Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
    if (sensorManager.registerListener(this, detectorSensor, SensorManager.SENSOR_DELAY_GAME)) {
      isAvailable = true;
      sensorMode = 0;
      Log.i(TAG, "计步传感器Detector可用！");
    } else if (sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_GAME)) {
      isAvailable = true;
      sensorMode = 1;
      Log.i(TAG, "计步传感器Counter可用！");
    } else {
      isAvailable = false;
      Log.i(TAG, "计步传感器不可用！");
    }
  }

  @Override
  public void unregisterStep() {
    sensorManager.unregisterListener(this);
  }

  @Override
  public void onSensorChanged(SensorEvent event) {
    liveStep = (int) event.values[0];
    if (sensorMode == 0) {
      Log.i(TAG, "Detector步数："+liveStep);
      StepSensorBase.CURRENT_SETP += liveStep;
    } else if (sensorMode == 1) {
      Log.i(TAG, "Counter步数："+liveStep);
      StepSensorBase.CURRENT_SETP = liveStep;
    }
    stepCallBack.Step(StepSensorBase.CURRENT_SETP);
  }

  @Override
  public void onAccuracyChanged(Sensor sensor, int accuracy) {
  }
}

三.使用加速度传感器实现计步

/**
 * 加速度传感器
 */
public class StepSensorAcceleration extends StepSensorBase {
  private final String TAG = "StepSensorAcceleration";
  //存放三轴数据
  final int valueNum = 5;
  //用于存放计算阈值的波峰波谷差值
  float[] tempValue = new float[valueNum];
  int tempCount = 0;
  //是否上升的标志位
  boolean isDirectionUp = false;
  //持续上升次数
  int continueUpCount = 0;
  //上一点的持续上升的次数，为了记录波峰的上升次数
  int continueUpFormerCount = 0;
  //上一点的状态，上升还是下降
  boolean lastStatus = false;
  //波峰值
  float peakOfWave = 0;
  //波谷值
  float valleyOfWave = 0;
  //此次波峰的时间
  long timeOfThisPeak = 0;
  //上次波峰的时间
  long timeOfLastPeak = 0;
  //当前的时间
  long timeOfNow = 0;
  //当前传感器的值
  float gravityNew = 0;
  //上次传感器的值
  float gravityOld = 0;
  //动态阈值需要动态的数据，这个值用于这些动态数据的阈值
  final float initialValue = (float) 1.7;
  //初始阈值
  float ThreadValue = (float) 2.0;

  //初始范围
  float minValue = 11f;
  float maxValue = 19.6f;

  /**
   * 0-准备计时  1-计时中 2-正常计步中
   */
  private int CountTimeState = 0;
  public static int TEMP_STEP = 0;
  private int lastStep = -1;
  //用x、y、z轴三个维度算出的平均值
  public static float average = 0;
  private Timer timer;
  // 倒计时3.5秒，3.5秒内不会显示计步，用于屏蔽细微波动
  private long duration = 3500;
  private TimeCount time;

  public StepSensorAcceleration(Context context, StepCallBack stepCallBack) {
    super(context, stepCallBack);
  }

  @Override
  protected void registerStepListener() {
    // 注册加速度传感器
    isAvailable = sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
        SensorManager.SENSOR_DELAY_GAME);
    if (isAvailable) {
      Log.i(TAG, "加速度传感器可用！");
    } else {
      Log.i(TAG, "加速度传感器不可用！");
    }
  }

  @Override
  public void unregisterStep() {
    sensorManager.unregisterListener(this);
  }

  public void onAccuracyChanged(Sensor arg0, int arg1) {
  }

  public void onSensorChanged(SensorEvent event) {
    Sensor sensor = event.sensor;
    synchronized (this) {
      if (sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
        calc_step(event);
      }
    }
  }

  synchronized private void calc_step(SensorEvent event) {
    average = (float) Math.sqrt(Math.pow(event.values[0], 2)
        + Math.pow(event.values[1], 2) + Math.pow(event.values[2], 2));
    detectorNewStep(average);
  }

  /*
   * 检测步子，并开始计步
   * 1.传入sersor中的数据
   * 2.如果检测到了波峰，并且符合时间差以及阈值的条件，则判定为1步
   * 3.符合时间差条件，波峰波谷差值大于initialValue，则将该差值纳入阈值的计算中
   * */
  public void detectorNewStep(float values) {
    if (gravityOld == 0) {
      gravityOld = values;
    } else {
      if (DetectorPeak(values, gravityOld)) {
        timeOfLastPeak = timeOfThisPeak;
        timeOfNow = System.currentTimeMillis();

        if (timeOfNow - timeOfLastPeak >= 200
            && (peakOfWave - valleyOfWave >= ThreadValue) && (timeOfNow - timeOfLastPeak) <= 2000) {
          timeOfThisPeak = timeOfNow;
          //更新界面的处理，不涉及到算法
          preStep();
        }
        if (timeOfNow - timeOfLastPeak >= 200
            && (peakOfWave - valleyOfWave >= initialValue)) {
          timeOfThisPeak = timeOfNow;
          ThreadValue = Peak_Valley_Thread(peakOfWave - valleyOfWave);
        }
      }
    }
    gravityOld = values;
  }

  private void preStep() {
//    if (CountTimeState == 0) {
//      // 开启计时器
//      time = new TimeCount(duration, 700);
//      time.start();
//      CountTimeState = 1;
//      Log.v(TAG, "开启计时器");
//    } else if (CountTimeState == 1) {
//      TEMP_STEP++;
//      Log.v(TAG, "计步中 TEMP_STEP:" + TEMP_STEP);
//    } else if (CountTimeState == 2) {
    StepSensorBase.CURRENT_SETP++;
//      if (stepCallBack != null) {
    stepCallBack.Step(StepSensorBase.CURRENT_SETP);
//      }
//    }

  }


  /*
   * 检测波峰
   * 以下四个条件判断为波峰：
   * 1.目前点为下降的趋势：isDirectionUp为false
   * 2.之前的点为上升的趋势：lastStatus为true
   * 3.到波峰为止，持续上升大于等于2次
   * 4.波峰值大于1.2g,小于2g
   * 记录波谷值
   * 1.观察波形图，可以发现在出现步子的地方，波谷的下一个就是波峰，有比较明显的特征以及差值
   * 2.所以要记录每次的波谷值，为了和下次的波峰做对比
   * */
  public boolean DetectorPeak(float newValue, float oldValue) {
    lastStatus = isDirectionUp;
    if (newValue >= oldValue) {
      isDirectionUp = true;
      continueUpCount++;
    } else {
      continueUpFormerCount = continueUpCount;
      continueUpCount = 0;
      isDirectionUp = false;
    }

//    Log.v(TAG, "oldValue:" + oldValue);
    if (!isDirectionUp && lastStatus
        && (continueUpFormerCount >= 2 && (oldValue >= minValue && oldValue < maxValue))) {
      peakOfWave = oldValue;
      return true;
    } else if (!lastStatus && isDirectionUp) {
      valleyOfWave = oldValue;
      return false;
    } else {
      return false;
    }
  }

  /*
   * 阈值的计算
   * 1.通过波峰波谷的差值计算阈值
   * 2.记录4个值，存入tempValue[]数组中
   * 3.在将数组传入函数averageValue中计算阈值
   * */
  public float Peak_Valley_Thread(float value) {
    float tempThread = ThreadValue;
    if (tempCount < valueNum) {
      tempValue[tempCount] = value;
      tempCount++;
    } else {
      tempThread = averageValue(tempValue, valueNum);
      for (int i = 1; i < valueNum; i++) {
        tempValue[i - 1] = tempValue[i];
      }
      tempValue[valueNum - 1] = value;
    }
    return tempThread;

  }

  /*
   * 梯度化阈值
   * 1.计算数组的均值
   * 2.通过均值将阈值梯度化在一个范围里
   * */
  public float averageValue(float value[], int n) {
    float ave = 0;
    for (int i = 0; i < n; i++) {
      ave += value[i];
    }
    ave = ave / valueNum;
    if (ave >= 8) {
//      Log.v(TAG, "超过8");
      ave = (float) 4.3;
    } else if (ave >= 7 && ave < 8) {
//      Log.v(TAG, "7-8");
      ave = (float) 3.3;
    } else if (ave >= 4 && ave < 7) {
//      Log.v(TAG, "4-7");
      ave = (float) 2.3;
    } else if (ave >= 3 && ave < 4) {
//      Log.v(TAG, "3-4");
      ave = (float) 2.0;
    } else {
//      Log.v(TAG, "else");
      ave = (float) 1.7;
    }
    return ave;
  }

  class TimeCount extends CountDownTimer {
    public TimeCount(long millisInFuture, long countDownInterval) {
      super(millisInFuture, countDownInterval);
    }

    @Override
    public void onFinish() {
      // 如果计时器正常结束，则开始计步
      time.cancel();
      StepSensorBase.CURRENT_SETP += TEMP_STEP;
      lastStep = -1;
      Log.v(TAG, "计时正常结束");

      timer = new Timer(true);
      TimerTask task = new TimerTask() {
        public void run() {
          if (lastStep == StepSensorBase.CURRENT_SETP) {
            timer.cancel();
            CountTimeState = 0;
            lastStep = -1;
            TEMP_STEP = 0;
            Log.v(TAG, "停止计步：" + StepSensorBase.CURRENT_SETP);
          } else {
            lastStep = StepSensorBase.CURRENT_SETP;
          }
        }
      };
      timer.schedule(task, 0, 2000);
      CountTimeState = 2;
    }

    @Override
    public void onTick(long millisUntilFinished) {
      if (lastStep == TEMP_STEP) {
        Log.v(TAG, "onTick 计时停止:" + TEMP_STEP);
        time.cancel();
        CountTimeState = 0;
        lastStep = -1;
        TEMP_STEP = 0;
      } else {
        lastStep = TEMP_STEP;
      }
    }
  }
}

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