java - 我怎样才能在我的 mainActivity 中实现这个类

Question

我发现这个类使用指南针，但在我发现它的网站中，他们没有解释如何实现它，我的意思是，当我在主 Activity 中调用该类并将结果仅放入结果一次，并且不要用值不断刷新屏幕...这是我找到的类:

public class Compass implements SensorEventListener{

private SensorManager sensorManager;
private Sensor gsensor;
private Sensor msensor;
private float[] mGravity = new float[3];
private float[] mGeomagnetic = new float[3];
private float azimuth = 0f;
private float correctAzimuth = 0;

public Compass(Context context){
    sensorManager = (SensorManager) context
                    .getSystemService(Context.SENSOR_SERVICE);
    gsensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    msensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
}

@Override
public void onSensorChanged(SensorEvent event) {
    final float alpha = 0.97f;

    synchronized (this) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {

            mGravity[0] = alpha * mGravity[0] + (1 - alpha)
                    * event.values[0];
            mGravity[1] = alpha * mGravity[1] + (1 - alpha)
                    * event.values[1];
            mGravity[2] = alpha * mGravity[2] + (1 - alpha)
                    * event.values[2];

            // mGravity = event.values;
            // Log.e(TAG, Float.toString(mGravity[0]));
        }

        if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {
            // mGeomagnetic = event.values;

            mGeomagnetic[0] = alpha * mGeomagnetic[0] + (1 - alpha)
                    * event.values[0];
            mGeomagnetic[1] = alpha * mGeomagnetic[1] + (1 - alpha)
                    * event.values[1];
            mGeomagnetic[2] = alpha * mGeomagnetic[2] + (1 - alpha)
                    * event.values[2];
            // Log.e(TAG, Float.toString(event.values[0]));

        }

        float R[] = new float[9];
        float I[] = new float[9];
        boolean success = SensorManager.getRotationMatrix(R, I, mGravity,
                mGeomagnetic);
        if (success) {
            float orientation[] = new float[3];
            SensorManager.getOrientation(R, orientation);
            // Log.d(TAG, "azimuth (rad): " + azimuth);
            azimuth = (float) Math.toDegrees(orientation[0]); // orientation
            azimuth = (azimuth + 360) % 360;
            // Log.d(TAG, "azimuth (deg): " + azimuth);
        }
    }
}

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

}

}

提前致谢!! :)

Answer 1

我尝试了代码，它对我有用 after我添加了

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION"/>

在 list 中。并添加了

    sensorManager.registerListener(this, gsensor, SensorManager.SENSOR_DELAY_NORMAL);
    sensorManager.registerListener(this, msensor, SensorManager.SENSOR_DELAY_NORMAL);

到 Compass 构造函数。

要访问罗盘值，您需要 Compass 类中方位角变量的 getter 方法。

Compass.onCreate:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    Compass compass = new Compass(this);
}

主要 Activity :

package com.example.myfirstapp;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.Log;

public class Compass implements SensorEventListener{

    private SensorManager sensorManager;
    private Sensor gsensor;
    private Sensor msensor;
    private float[] mGravity = new float[3];
    private float[] mGeomagnetic = new float[3];
    private float azimuth = 0f;
    private float correctAzimuth = 0;
    private String TAG = "Compass";

    public Compass(Context context)
    {
        sensorManager = (SensorManager) context
                    .getSystemService(Context.SENSOR_SERVICE);
        gsensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        msensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);

        sensorManager.registerListener(this, gsensor, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, msensor, SensorManager.SENSOR_DELAY_NORMAL);
    }

    @Override
    public void onSensorChanged(SensorEvent event) 
    {
        final float alpha = 0.97f;

        synchronized (this) 
        {
            if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) 
            {

                mGravity[0] = alpha * mGravity[0] + (1 - alpha)
                    * event.values[0];
                mGravity[1] = alpha * mGravity[1] + (1 - alpha)
                    * event.values[1];
                mGravity[2] = alpha * mGravity[2] + (1 - alpha)
                    * event.values[2];

                // mGravity = event.values;
                // Log.e(TAG, Float.toString(mGravity[0]));
            }

            if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) 
            {
                // mGeomagnetic = event.values;

                mGeomagnetic[0] = alpha * mGeomagnetic[0] + (1 - alpha)
                    * event.values[0];
                mGeomagnetic[1] = alpha * mGeomagnetic[1] + (1 - alpha)
                    * event.values[1];
                mGeomagnetic[2] = alpha * mGeomagnetic[2] + (1 - alpha)
                    * event.values[2];
                // Log.e(TAG, Float.toString(event.values[0]));

            }

            float R[] = new float[9];
            float I[] = new float[9];
            boolean success = SensorManager.
                    getRotationMatrix(R, I, mGravity, mGeomagnetic);
            if (success) 
            {
                float orientation[] = new float[3];
                SensorManager.getOrientation(R, orientation);
                // Log.d(TAG, "azimuth (rad): " + azimuth);
                azimuth = (float) Math.toDegrees(orientation[0]); // orientation
                azimuth = (azimuth + 360) % 360;

                Log.d(TAG, "azimuth (deg): " + azimuth);
            }
        }
    }

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

    }

}