Android实现罗盘功能_Android

Android实现指南针功能

（1）布局文件如下：

<?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:gravity="center"    android:orientation="vertical" >    <ImageView        android:id="@+id/imageView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:src="@drawable/zn" /></LinearLayout>

所需图片：
这里写图片描述

（2）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;    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);        manager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);    }    @Override    protected void onResume() {        Sensor sensor = manager.getDefaultSensor(Sensor.TYPE_ORIENTATION);        manager.registerListener(listener, sensor,                SensorManager.SENSOR_DELAY_GAME);        super.onResume();    }    @Override    protected void onPause() {        manager.unregisterListener(listener);        super.onPause();    }    private final class SensorListener implements SensorEventListener {        private float predegree = 0;        public void onSensorChanged(SensorEvent event) {            float degree = event.values[0];// 存放了方向值 90            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;        }        public void onAccuracyChanged(Sensor sensor, int accuracy) {        }    }}

效果如下：
这里写图片描述