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);
    }
}