Android : Compass

Fail : AndroidCompass.java

package com.exercise.AndroidCompass;

import java.util.List;

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.widget.Toast;

public class AndroidCompass extends Activity {
	
	private static SensorManager mySensorManager;
	private boolean sersorrunning;
	private MyCompassView myCompassView;
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        myCompassView = (MyCompassView)findViewById(R.id.mycompassview);
        
        mySensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        List<Sensor> mySensors = mySensorManager.getSensorList(Sensor.TYPE_ORIENTATION);
        
        if(mySensors.size() > 0){
        	mySensorManager.registerListener(mySensorEventListener, mySensors.get(0), SensorManager.SENSOR_DELAY_NORMAL);
        	sersorrunning = true;
        	Toast.makeText(this, "Start ORIENTATION Sensor", Toast.LENGTH_LONG).show();	
        	
        }
        else{
        	Toast.makeText(this, "No ORIENTATION Sensor", Toast.LENGTH_LONG).show();
        	sersorrunning = false;
        	finish();	
        }
    }
    
    private SensorEventListener mySensorEventListener = new SensorEventListener(){

		@Override
		public void onAccuracyChanged(Sensor sensor, int accuracy) {
			// TODO Auto-generated method stub
			
		}

		@Override
		public void onSensorChanged(SensorEvent event) {
			// TODO Auto-generated method stub
			myCompassView.updateDirection((float)event.values[0]);
		}
    };

	@Override
	protected void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy();
		
		if(sersorrunning){
			mySensorManager.unregisterListener(mySensorEventListener);	
		}
	}

}

Fail : MyCompassView.java

package com.exercise.AndroidCompass;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class MyCompassView extends View {

	private float direction = 0;
	private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
	private boolean firstDraw;
	
	public MyCompassView(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		init();
	}

	public MyCompassView(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
		init();
	}

	public MyCompassView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// TODO Auto-generated constructor stub
		init();
	}
	
	private void init(){
		
		paint.setStyle(Paint.Style.STROKE);
		paint.setStrokeWidth(3);
		paint.setColor(Color.WHITE);
		paint.setTextSize(30);
		
		firstDraw = true;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		// TODO Auto-generated method stub
		setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.getSize(heightMeasureSpec));
	}

	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		 
		int cxCompass = getMeasuredWidth()/2;
		int cyCompass = getMeasuredHeight()/2;
		float radiusCompass;
		
		if(cxCompass > cyCompass){
			radiusCompass = (float) (cyCompass * 0.9);
		}
		else{
			radiusCompass = (float) (cxCompass * 0.9);
		}
		canvas.drawCircle(cxCompass, cyCompass, radiusCompass, paint);
		canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), paint);
		
		if(!firstDraw){
		
			canvas.drawLine(cxCompass, cyCompass, 
					(float)(cxCompass + radiusCompass * Math.sin((double)(-direction) * 3.14/180)), 
					(float)(cyCompass - radiusCompass * Math.cos((double)(-direction) * 3.14/180)), 
					paint);
		
			canvas.drawText(String.valueOf(direction), cxCompass, cyCompass, paint);
		}
		
	}
	
	public void updateDirection(float dir)
	{
		firstDraw = false;
		direction = dir;
		invalidate();
	}
	

}

Fail : AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.exercise.AndroidCompass"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".AndroidCompass"
                  android:label="@string/app_name"
                  android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
    <uses-sdk android:minSdkVersion="4" />

</manifest> 

Fail : main.xml

<?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"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<view
	class="com.exercise.AndroidCompass.MyCompassView"
	android:id="@+id/mycompassview"
	android:layout_width="fill_parent"
	android:layout_height="fill_parent"
	/>
</LinearLayout>