1.新建Module,activity_main.xml中定義一個TextView,用來顯示光照強度：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/light_level"
 

        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:textSize="20sp"/>
</RelativeLayout>

2.MainActivity.java:

package com.imooc.lightsensortest;

import android.content.Context;
import android.hardware.Sensor;
import
 
 android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private SensorManager sensorManager;//系統所有感測器的管理器,有了它的例項後就可以呼叫getDefaultSensor()方法來得到任意的感測器型別
 

    private TextView lightLevel;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lightLevel=(TextView)findViewById(R.id.light_level);
        sensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE);
        Sensor sensor=sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
        //三個引數:1.SensorEventListener的例項 2.Sensor的例項 3.用於表示感測器輸出資訊的更新速率
        //引數三有4個值：SENSOR_DELAY_UI,SENSOR_DELAY_NORMAL,SENSOR_DELAY_GAME,SENSOR_DELAY_FASTEST，更新速率依次遞增
        sensorManager.registerListener(listener,sensor,SensorManager.SENSOR_DELAY_NORMAL);
    }

    private SensorEventListener listener=new SensorEventListener() {
        @Override
        public void onSensorChanged(SensorEvent event) {
            //values陣列中第一個下標的值就是當前的光照強度
            float value=event.values[0];
            lightLevel.setText("Current light level is"+value+"lx");//單位：勒克斯
        }

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

        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(sensorManager!=null){
            sensorManager.unregisterListener(listener);//onDestory()方法中呼叫unregisterListener()方法釋放使用的資源
        }
    }
}