显示当前光照强度

src目录下MainActivity.java代码如下: 1 package com.example.guangzhao;
 2
 3
 4
 5 import android.os.Bundle;
 6 import android.app.Activity;
 7 import android.content.Context;
 8 import android.hardware.Sensor;
 9 import android.hardware.SensorEvent;
10 import android.hardware.SensorEventListener;
11 import android.hardware.SensorManager;
12 import android.view.Menu;
13 import android.widget.TextView;
14
15 public class MainActivity extends Activity {
16
17     private SensorManager sensorManager;
18     private TextView lightLevel;
19
20     @Override
21     protected void onCreate(Bundle savedInstanceState) {
22         super.onCreate(savedInstanceState);
23         setContentView(R.layout.activity_main);
24         lightLevel = (TextView) findViewById(R.id.light);
25         sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
26         Sensor sensor = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
27         Sensor sensors;
28         sensorManager.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_NORMAL);
29     }
30
31     protected void onDestory() {
32         super.onDestroy();
33         if (sensorManager != null) {
34             sensorManager.unregisterListener(listener);
35         }
36     }
37
38     private SensorEventListener listener = new SensorEventListener() {
39         @Override
40         public void onSensorChanged(SensorEvent event) {
41             // valuse 数组中第一个下标的值就是当前的光照强度
42             float value = event.values[0];
43             lightLevel.setText("当前光照强度为" + value + "勒克斯");
44         }
45
46         @Override
47         public void onAccuracyChanged(Sensor sensor, int accuracy) {
48
49         }
50     };
51 }

activity_main.xml代码如下：

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

</RelativeLayout>