38

我需要有关如何检测 android 设备的移动量的建议。假设我将手机放在桌子或床上，然后如果有人轻敲桌子或坐在床上或躺在床上，那么我想检测 android 设备的移动。

实际上我知道 android 有运动传感器 API，但我不知道使用哪种传感器以及哪种传感器类型最适合这种类型的运动检测。

如果有人可以分享一些基本的演示代码，我会很高兴。

4

6 回答 6

63

绝对可以使用加速度计：

// Start with some variables
private SensorManager sensorMan;
private Sensor accelerometer;

private float[] mGravity;
private float mAccel;
private float mAccelCurrent;
private float mAccelLast;

// In onCreate method
sensorMan = (SensorManager)getSystemService(SENSOR_SERVICE);
accelerometer = sensorMan.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mAccel = 0.00f;
mAccelCurrent = SensorManager.GRAVITY_EARTH;
mAccelLast = SensorManager.GRAVITY_EARTH;

// And these:

@Override
public void onResume() {
    super.onResume();
    sensorMan.registerListener(this, accelerometer,
        SensorManager.SENSOR_DELAY_UI);
}

@Override
protected void onPause() {
    super.onPause();
    sensorMan.unregisterListener(this);
}

@Override
public void onSensorChanged(SensorEvent event) {
    if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER){
        mGravity = event.values.clone();
        // Shake detection
        float x = mGravity[0];
        float y = mGravity[1];
        float z = mGravity[2];
        mAccelLast = mAccelCurrent;
        mAccelCurrent = FloatMath.sqrt(x*x + y*y + z*z);
        float delta = mAccelCurrent - mAccelLast;
        mAccel = mAccel * 0.9f + delta;
            // Make this higher or lower according to how much
            // motion you want to detect
        if(mAccel > 3){ 
        // do something
        }
    }

}

@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
    // required method
}
于 2013-01-29T03:05:49.623 回答
18

我使用了以下课程：

public class MovementDetector implements SensorEventListener {

protected final String TAG = getClass().getSimpleName();

private SensorManager sensorMan;
private Sensor accelerometer;

private MovementDetector() {
}

private static MovementDetector mInstance;

public static MovementDetector getInstance() {
    if (mInstance == null) {
        mInstance = new MovementDetector();
        mInstance.init();
    }
    return mInstance;
}

//////////////////////
private HashSet<Listener> mListeners = new HashSet<MovementDetector.Listener>();

private void init() {
    sensorMan = (SensorManager) GlobalData.getInstance().getContext().getSystemService(Context.SENSOR_SERVICE);
    accelerometer = sensorMan.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);
}

public void start() {
    sensorMan.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}

public void stop() {
    sensorMan.unregisterListener(this);
}

public void addListener(Listener listener) {
    mListeners.add(listener);
}

/* (non-Javadoc)
 * @see android.hardware.SensorEventListener#onSensorChanged(android.hardware.SensorEvent)
 */
@Override
public void onSensorChanged(SensorEvent event) {
    if (event.sensor.getType() == Sensor.TYPE_LINEAR_ACCELERATION) {

        float x = event.values[0];
        float y = event.values[1];
        float z = event.values[2];

        float diff = (float) Math.sqrt(x * x + y * y + z * z);
        if (diff > 0.5) // 0.5 is a threshold, you can test it and change it
            Log.d(TAG,"Device motion detected!!!!");
        for (Listener listener : mListeners) {
            listener.onMotionDetected(event, diff);
        }
    }

}

/* (non-Javadoc)
 * @see android.hardware.SensorEventListener#onAccuracyChanged(android.hardware.Sensor, int)
 */
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
    // TODO Auto-generated method stub

}

public interface Listener {
    void onMotionDetected(SensorEvent event, float acceleration);
    }
}

用法：

在我的活动中onCrate()：

        MovementDetector.getInstance().addListener(new MovementDetector.Listener() {

        @Override
        public void onMotionDetected(SensorEvent event, float acceleration) {

            mMotionDetectionTextView.setText("Acceleration: ["+String.format("%.3f",event.values[0])+","+String.format("%.3f",event.values[1])+","+String.format("%.3f",event.values[2])+"] "+String.format("%.3f", acceleration));
            if (acceleration > SettingsHelper.getInstance().getMotionDetectionThreshold()){
                mMotionDetectionTextView.setTextColor(Color.RED);
            } else {
                mMotionDetectionTextView.setTextColor(Color.WHITE);
            }

        }
    });

在我的活动中onResume()：

MovementDetector.getInstance().start();

在我的活动中onPause()：

MovementDetector.getInstance().stop();
于 2015-06-22T17:47:58.027 回答
5

此代码用于步行检测（修改自@anthropomo 代码）

以获得更平滑的价值。

// 初始化

private SensorManager sensorMan;
private Sensor accelerometer;

private float[] mGravity;
private double mAccel;
private double mAccelCurrent;
private double mAccelLast;

private boolean sensorRegistered = false;

// onCreate

    sensorMan = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
    accelerometer = sensorMan.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccel = 0.00f;
    mAccelCurrent = SensorManager.GRAVITY_EARTH;
    mAccelLast = SensorManager.GRAVITY_EARTH;

    sensorMan.registerListener(this, accelerometer,
            SensorManager.SENSOR_DELAY_NORMAL);
    sensorRegistered = true;

// onSensorChanged

private int hitCount = 0;
private double hitSum = 0;
private double hitResult = 0;

private final int SAMPLE_SIZE = 50; // change this sample size as you want, higher is more precise but slow measure.
private final double THRESHOLD = 0.2; // change this threshold as you want, higher is more spike movement

@Override
public void onSensorChanged(SensorEvent event) {
    if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
        mGravity = event.values.clone();
        // Shake detection
        double x = mGravity[0];
        double y = mGravity[1];
        double z = mGravity[2];
        mAccelLast = mAccelCurrent;
        mAccelCurrent = Math.sqrt(x * x + y * y + z * z);
        double delta = mAccelCurrent - mAccelLast;
        mAccel = mAccel * 0.9f + delta;

        if (hitCount <= SAMPLE_SIZE) {
            hitCount++;
            hitSum += Math.abs(mAccel);
        } else {
            hitResult = hitSum / SAMPLE_SIZE;

            Log.d(TAG, String.valueOf(hitResult));

            if (hitResult > THRESHOLD) {
                Log.d(TAG, "Walking");
            } else {
                Log.d(TAG, "Stop Walking");
            }

            hitCount = 0;
            hitSum = 0;
            hitResult = 0;
        }
    }
}
于 2016-07-27T04:53:36.743 回答
0

虽然我没有演示代码（因为您不够具体），但这里有一个好的开始：http: //developer.android.com/guide/topics/sensors/sensors_motion.html（以及左侧的其他项目）。

于 2013-01-29T02:56:04.450 回答
0

如果你想找到手机的位移，你需要找到作用在手机上的线性加速度，而不是重力加速度

android有一个内置的转换器来找到你手机上的LINEAR ACCELERATION

https://github.com/yuvaramsingh94/AndroidSensorTestCode/tree/master

这是一个代码，您可以在其中查看如何获取 LINEAR ACCELERATION 的原始值

于 2017-01-29T16:18:25.610 回答
0

我一直在用类似的想法来测量手机的位移。我发现LINEAR ACCELERATION（和ACCELERATION）不够准确，无法正确测量位移。

这段代码应该工作得更好一点：

（初始化）

private SensorManager sensorManager;
private Sensor accelerometer;
double[] maxAccelerations = new double[3];
double[] position = new double[3];
long[] times = new long[3];
// time combined with maxAcceleration can approximate the change in position,
// with the formula Δpos = (maxAcceleration * time ^ 2) / 6
long currentTime;

(onCreate)

sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
if (sensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION) != null) {
    accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);
        sensorManager.registerListener(this, accelerometer, sensorManager.SENSOR_DELAY_FASTEST);
}
currentTime = System.currentTimeMillis();
for(int i=0;i<3;i++){
    times[i]=currentTime;
}
else{
    throw "Error";
    //Which will throw an error, if not the error that is expected. 
}

（onSensorChanged 和 onAccuracyChanged）

@Override
public void onAccuracyChanged(Sensor ignore, int thisFunction) {
}

@Override
public void onSensorChanged(SensorEvent event) {
    if (event.sensor.getType() == Sensor.TYPE_LINEAR_ACCELERATION) {
        for(int i=0;i<3;i++){
            if(Math.abs(event.values[i])<0.01){
                // Note: this is to try to prevent accelerating time from being counted when the phone is stationary. 0.01 should be
                // changed to an appropriate sensitivity level that can be calculated by finding an average noise level when the phone is stationary.
                times[i]=System.currentTimeMillis();
            }
            if(event.values[i]>maxAccelerations[i] && maxAccelerations[i]>=0){
                maxAccelerations[i]=event.values[i];
            }
            else if(event.values[i]<maxAccelerations[i] && maxAccelerations[i]<=0){
                maxAccelerations[i]=event.values[i];
            }
            else if(event.values[i]>0 && maxAccelerations[i]<0){
                currentTime = System.currentTimeMillis();
                position[i]+=maxAccelerations[i] * (times[i]-currentTime)*(times[i]-currentTime) / 6;
                times[i]=currentTime;
                maxAccelerations[i]=event.values[i];
            }
            else if(event.values[i]<0 && maxAccelerations[i]>0){
                currentTime = System.currentTimeMillis();
                position[i]+=maxAccelerations[i] * (times[i]-currentTime)*(times[i]-currentTime) / 6;
                times[i]=currentTime;
                maxAccelerations[i]=event.values[i];
            }
        }
    }
}
于 2018-11-20T16:38:33.003 回答