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作者：倪鍵樹，嵌入式安卓物聯網講師。
Android傳感器編程實例開發——三軸數據採集
一、概述
Android支持的傳感器種類越來越多，這是一件非常可喜的事情，本節就來介紹一下在Android系統下的傳感器編程。Android，讓我們再一次看到了你的強大！會讓我們更加堅定學習Android開發的信心！
二、要求
瞭解、熟悉傳感器的編程方法。
三、實現
新建工程MySensor，修改/res/layout/main.xml文件，在裏面添加一個SurfaceView，完整的main.xml文件如下：
1<?xmlversion="1.0" encoding="utf-8"?>
2<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3 android:layout_width="fill_parent"
4 android:layout_height="fill_parent"
5 android:orientation="vertical">
6
7<SurfaceView
8android:id="@+id/surfaceview"
9 android:layout_width="fill_parent"
10 android:layout_height="180dip"
11/>
12
13
14</LinearLayout>
接着，修改MySensorActivity.java文件，代碼中有詳細註釋，完整的MySensorActivity.java文件如下：
1package com.nan.sensor;
2
3importandroid.app.Activity;
4importandroid.graphics.Canvas;
5importandroid.graphics.Color;
6importandroid.graphics.Paint;
7importandroid.graphics.Rect;
8importandroid.hardware.Sensor;
9import android.hardware.SensorEvent;
10importandroid.hardware.SensorEventListener;
11importandroid.hardware.SensorManager;
12importandroid.os.Bundle;
13importandroid.view.SurfaceHolder;
14importandroid.view.SurfaceView;
15
16publicclass MySensorActivity extends Activity
17 {
18privatefloat acceValusX = 0f;
19privatefloat acceValusY = 0f;
20privatefloat acceValusZ = 0f;
21privateint x = 0;
22
23private SurfaceView mSurfaceView = null;
24private SurfaceHolder mSurfaceHolder = null;
25private Paint mPaint = null;
26
27private SensorManager mSensorManager;
28private Sensor mAccelerometer;
29private OnSensorEventListener mOnSensorEventListener= new OnSensorEventListener();
30
31/** Called when the activity is firstcreated. */
32 @Override
33publicvoid onCreate(Bundle savedInstanceState)
34
35 {
36super.onCreate(savedInstanceState);
37 setContentView(R.layout.main);
38
39 mSurfaceView = (SurfaceView)findViewById(R.id.surfaceview);
40 mSurfaceHolder = mSurfaceView.getHolder();
41 mSurfaceHolder.addCallback(new MyHolder());
42
43 mPaint = new Paint();
44//畫筆的粗細
45 mPaint.setStrokeWidth(1.0f);
46//從系統服務中獲得傳感器管服務
47 mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
48 mAccelerometer =mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
49//註冊傳感器監聽
50 mSensorManager.registerListener(mOnSensorEventListener, mAccelerometer,SensorManager.SENSOR_DELAY_GAME);
51 }
52
53
54privateclass OnSensorEventListener implementsSensorEventListener
55 {
56
57 @Override
58publicvoid onAccuracyChanged(Sensor sensor, int accuracy)
59 {
60// TODO Auto-generated method stub
61
62 }
63
64 @Override
65publicvoid onSensorChanged(SensorEvent event)
66 {
67// TODO Auto-generated method stub
68
69//獲得x軸的值
70 acceValusX = event.values[0];
71//獲得y軸的值
72 acceValusY = event.values[1];
73//獲得z軸的值
74 acceValusZ = event.values[2];
75
76//鎖定整個SurfaceView
77 CanvasmCanvas = mSurfaceHolder.lockCanvas();
78try
79 {
80if(mCanvas!=null)
81 {
82//畫筆的顏色(紅)
83 mPaint.setColor(Color.RED);
84//畫X軸的點
85 mCanvas.drawPoint(x, (int)(30 +acceValusX), mPaint);
86//畫筆的顏色(綠)
87 mPaint.setColor(Color.GREEN);
88//畫Y軸的點
89 mCanvas.drawPoint(x, (int)(60 +acceValusY), mPaint);
90//畫筆的顏色(藍)
91 mPaint.setColor(Color.BLUE);
92//畫Z軸的點
93 mCanvas.drawPoint(x, (int)(90 +acceValusZ), mPaint);
94//橫座標+1
95 x++;
96//如果已經畫到了屏幕的最右邊
97if(x >getWindowManager().getDefaultDisplay().getWidth())
98 {
99 x = 0;
100//清屏
101 mCanvas.drawColor(Color.BLACK);
102 }
103//繪製完成，提交修改
104 mSurfaceHolder.unlockCanvasAndPost(mCanvas);
105 }
106 }
107catch(Exception e)
108 {
109 e.printStackTrace();
110 }
111finally
112 {
113if(mCanvas!=null)
114 {
115//重新鎖一次
116 mSurfaceHolder.lockCanvas(new Rect(0, 0, 0, 0));
117 mSurfaceHolder.unlockCanvasAndPost(mCanvas);
118 }
119 }
120
121 }
122
123 }
124
125
126//定義一個類，實現Callback接口
127publicclass MyHolder implements SurfaceHolder.Callback
128 {
129
130publicvoid surfaceChanged(SurfaceHolder holder, int format, int width,
131int height)
132 {
133// TODO Auto-generated method stub
134//add your code
135 }
136
137publicvoid surfaceCreated(SurfaceHolder holder)
138 {
139// TODO Auto-generated method stub
140//add your code
141 }
142
143publicvoid surfaceDestroyed(SurfaceHolder holder)
144 {
145// TODO Auto-generated method stub
146//add your code
147 }
148
149 }
150
151 @Override
152publicvoid onDestroy()
153 {
154super.onDestroy();
155//註銷傳感器監聽
156 mSensorManager.unregisterListener(mOnSensorEventListener,mAccelerometer);
157 }
158
159 }
好了，在真機上運行它，效果如下：
晃動手機幾下，效果如下：
完成。