Android 利用方向传感器实现指南针具体步骤

step1:新建一个项目compass,并将一张指南针图片导入到res/drawable-hdpi目录中
 
step2:设计应用的ui界面,main.xml

<span style="font-size: 18px"><strong><?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
>
<imageview
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/compass"
android:id="@+id/imageview"
/>
</linearlayout></strong></span>

step3：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;
import android.view.animation.animation;
import android.view.animation.rotateanimation;
import android.widget.imageview;
public class mainactivity extends activity {
private imageview imageview;
/** 传感器管理器 */
private sensormanager manager;
private sensorlistener listener = new sensorlistener();
@override
public void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.main);
imageview = (imageview) this.findviewbyid(r.id.imageview);
imageview.setkeepscreenon(true);//屏幕高亮
//获取系统服务（sensor_service)返回一个sensormanager 对象
manager = (sensormanager) getsystemservice(context.sensor_service);
}
@override
protected void onresume() {
/**
* 获取方向传感器
* 通过sensormanager对象获取相应的sensor类型的对象
*/
sensor sensor = manager.getdefaultsensor(sensor.type_orientation);
//应用在前台时候注册监听器
manager.registerlistener(listener, sensor,
sensormanager.sensor_delay_game);
super.onresume();
}
@override
protected void onpause() {
//应用不在前台时候销毁掉监听器
manager.unregisterlistener(listener);
super.onpause();
}
private final class sensorlistener implements sensoreventlistener {
private float predegree = 0;
@override
public void onsensorchanged(sensorevent event) {
/**
* values[0]: x-axis 方向加速度
　　 values[1]: y-axis 方向加速度
　　 values[2]: z-axis 方向加速度
*/
float degree = event.values[0];// 存放了方向值
/**动画效果*/
rotateanimation animation = new rotateanimation(predegree, degree,
animation.relative_to_self,0.5f,animation.relative_to_self,0.5f);
animation.setduration(200);
imageview.startanimation(animation);
predegree=-degree;

/**
float x=event.values[sensormanager.data_x];
float y=event.values[sensormanager.data_y];
float z=event.values[sensormanager.data_z];
log.i("xyz", "x="+(int)x+",y="+(int)y+",z="+(int)z);
*/
}
@override
public void onaccuracychanged(sensor sensor, int accuracy) {
}
}
}

step4:androidmanifest.xml

<span style="font-size: 18px"><strong><?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cn.roco.sensor"
android:versioncode="1"
android:versionname="1.0">
<uses-sdk android:minsdkversion="8" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name="mainactivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.main" />
<category android:name="android.intent.category.launcher" />
</intent-filter>
</activity>
</application>
</manifest></strong></span>