Android(安卓)指南针

开发指南针思路很简单：准备一张指南针图片，该图片上方向指针指向北方。接下来开发一个检测方向的传感器，程序检测到手机顶部绕Z轴转过多少度，让指南针图片反向转过多少度即可。

程序代码：

package org.crazyit.sensor;import android.app.Activity;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 Compass extends Activity implements SensorEventListener {// 定义显示指南针的图片ImageView znzImage;// 记录指南针图片转过的角度float currentDegree = 0f;// 定义Sensor管理器SensorManager mSensorManager;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);// 获取界面中显示指南针的图片znzImage = (ImageView) findViewById(R.id.znzImage);// 获取传感器管理服务mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);}@Overrideprotected void onResume() {super.onResume();// 为系统的方向传感器注册监听器mSensorManager.registerListener(this,mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),SensorManager.SENSOR_DELAY_GAME);}@Overrideprotected void onPause() {// 取消注册mSensorManager.unregisterListener(this);super.onPause();}@Overrideprotected void onStop() {// 取消注册mSensorManager.unregisterListener(this);super.onStop();}@Overridepublic void onSensorChanged(SensorEvent event) {// 获取触发event的传感器类型int sensorType = event.sensor.getType();switch (sensorType) {case Sensor.TYPE_ORIENTATION:// 获取绕Z轴转过的角度。float degree = event.values[0];<strong>// 创建旋转动画（反向转过degree度）RotateAnimation ra = new RotateAnimation(currentDegree, -degree,Animation.RELATIVE_TO_SELF, 0.5f,Animation.RELATIVE_TO_SELF, 0.5f);</strong>// 设置动画的持续时间ra.setDuration(200);// 运行动画znzImage.startAnimation(ra);currentDegree = -degree;break;}}@Overridepublic void onAccuracyChanged(Sensor sensor, int accuracy) {}}

布局文件:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:background="#fff"    android:orientation="vertical" >    <ImageView        android:id="@+id/znzImage"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:scaleType="fitCenter"        android:src="@drawable/znz" /></LinearLayout>

演示结果：

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