將感測器模擬軟體的數值傳送到車用虛擬儀表

今天教導學生如何安裝SensorSimulator的軟體，並將感測器的模擬訊號當成汽車的時速值，我還修改了SensorDemo部份程式，讓它能顯示虛擬儀表，其程式如下(粗體字為新增部份、斜體字為刪除部份)：

package org.openintents.samples.SensorDemo;

import org.openintents.sensorsimulator.hardware.SensorManagerSimulator;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.hardware.SensorListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class SensorDemoActivity extends Activity implements SensorListener {

    private SensorManagerSimulator mSensorManager;
    
    TextView mTextView1;
    TextView mTextView2;
    TextView mTextView3;

 private float[] Oritation;

 private VirtualMeterView mVirtualMeterView;
    
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
  //      setContentView(R.layout.main);
 Oritation = new float[3];
        mVirtualMeterView=new VirtualMeterView(this);
        setContentView(mVirtualMeterView);      
/*        mTextView1 = (TextView) findViewById(R.id.text1);
        mTextView2 = (TextView) findViewById(R.id.text2);
        mTextView3 = (TextView) findViewById(R.id.text3);*/
 
        ////////////////////////////////////////////////////////////////
        // INSTRUCTIONS
        // ============

        // 1) Use the separate application SensorSimulatorSettings
        //    to enter the correct IP address of the SensorSimulator.
        //    This should work before you proceed, because the same
        //    settings are used for your custom sensor application.

        // 2) Include sensorsimulator-lib.jar in your project.
        //    Put that file into the 'lib' folder.
        //    In Eclipse, right-click on your project in the 
        //    Package Explorer, select
        //    Properties > Java Build Path > (tab) Libraries
        //    then click Add JARs to add this jar.

        // 3) You need the permission
        //    
        //    in your Manifest file!

        // 4) Instead of calling the system service to obtain the Sensor manager,
        //    you should obtain it from the SensorManagerSimulator:

        //mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        mSensorManager = SensorManagerSimulator.getSystemService(this, SENSOR_SERVICE);

        // 5) Connect to the sensor simulator, using the settings
        //    that have been set previously with SensorSimulatorSettings
        mSensorManager.connectSimulator();

        // The rest of your application can stay unmodified.
        ////////////////////////////////////////////////////////////////

    }
    

    
 @Override
 protected void onResume() {
  super.onResume();
  mSensorManager.registerListener(this, SensorManager.SENSOR_ACCELEROMETER
    | SensorManager.SENSOR_MAGNETIC_FIELD
    | SensorManager.SENSOR_ORIENTATION,
    SensorManager.SENSOR_DELAY_FASTEST);
 }

 @Override
 protected void onStop() {
  mSensorManager.unregisterListener(this);
  super.onStop();
 }

 public void onAccuracyChanged(int sensor, int accuracy) {
 }

 public void onSensorChanged(int sensor, float[] values) {
  switch(sensor) {
/*  case SensorManager.SENSOR_ACCELEROMETER:
   mTextView1.setText("Accelerometer: " 
     + values[0] + ", " 
     + values[1] + ", "
     + values[2]);
   break;
  case SensorManager.SENSOR_MAGNETIC_FIELD:
   mTextView2.setText("Compass: " 
     + values[0] + ", " 
     + values[1] + ", "
     + values[2]);
   break;*/
  case SensorManager.SENSOR_ORIENTATION:

/*   mTextView3.setText("Orientation: " 
     + values[0] + ", " 
     + values[1] + ", "
     + values[2]);*/

   for(int i=0; i<3; i++)
    Oritation[i]=values[i];
   mVirtualMeterView.invalidate();   break;
  }
 }
    private class VirtualMeterView extends View{
  private static final String TEXTONMETER = "0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300";
  private Path mPath;

  public VirtualMeterView(Context context) {
   super(context);
   // TODO Auto-generated constructor stub

   mPath = new Path();
   RectF oval = new RectF(40,20,260,240);
   mPath.addArc(oval , 120, 300);
   


  }

  @Override
  protected void onDraw(Canvas canvas) {
   // TODO Auto-generated method stub
   super.onDraw(canvas);
   Paint paint = new Paint();;
   RectF oval = new RectF(50,30,250,230);
   paint.setColor(Color.BLUE);
   paint.setStyle(Paint.Style.STROKE);
   canvas.drawArc(oval , 120, 300, true, paint );
   
   paint.setStyle(Paint.Style.FILL);
   paint.setColor(Color.RED);
   paint.setTextSize(20);
   paint.setTextAlign(Paint.Align.CENTER);
   canvas.drawTextOnPath(TEXTONMETER, mPath, 0, 0, paint); 
   
   float angle;
   if(Oritation[0]>300)
    angle = 300;
   else 
    angle = Oritation[0];
   float x = (float) (105 * Math.cos((120+angle)/180*3.14));
   float y = (float) (105 * Math.sin((120+angle)/180*3.14));
   canvas.drawLine(150+x, 130+y, 150, 130, paint);
  }
     
    }
}