ANDROID_MARS学习笔记_S05_004_过滤杂质，得到真正的加速度

一、简介

二、代码
1.java

(1)MainActivity.java

 import android.app.Activity;
 import android.content.Context;
 import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
 import android.os.Bundle;

 public class MainActivity extends Activity {
     /** Called when the activity is first created. */

     private SensorManager sensorManager;
     private Sensor accelerometerSensor;
     private float gravity [] = new float[3];
     private float linear_acceleration [] = new float[3];
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         sensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
         accelerometerSensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
         sensorManager.registerListener(new SensorEventListener() {

             public void onSensorChanged(SensorEvent event) {

                 /*System.out.println("x---" + event.values[0]);
                 System.out.println("y---" + event.values[1]);
                 System.out.println("z---" + event.values[2]);*/
                   final float alpha = 0.8f;

                   //用滤波器过滤掉杂质
                   gravity[0] = alpha * gravity[0] + (1 - alpha) * event.values[0];
                   gravity[1] = alpha * gravity[1] + (1 - alpha) * event.values[1];
                   gravity[2] = alpha * gravity[2] + (1 - alpha) * event.values[2];

                   linear_acceleration[0] = event.values[0] - gravity[0];
                   linear_acceleration[1] = event.values[1] - gravity[1];
                   linear_acceleration[2] = event.values[2] - gravity[2];

                   System.out.println(linear_acceleration[0]);
                   System.out.println(linear_acceleration[1]);
                   System.out.println(linear_acceleration[2]);
 //                  System.out.println(gravity[0]);
 //                  System.out.println(gravity[1]);
 //                  System.out.println(gravity[2]);
             }

             public void onAccuracyChanged(Sensor sensor, int accuracy) {

             }
         }, accelerometerSensor, SensorManager.SENSOR_DELAY_NORMAL);
     }
 }