変数「azimuth_angle」があります
画面をタッチして方向を変えるといいですね
変数「azimuth_angle」が減少します
私のコードで
画面に触れると変数が減少します
しかし、それがうまくいかない方向を変える
同じinvalidate()を使用します
これの何が悪いの??
public class HelloCamera extends Activity implements SensorEventListener
{
    private MyView mView;
    float azimuth_angle = 365;
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        mView = new MyView(this);       
        setContentView(new HelloCameraPreview(this));
        addContentView(mView, new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
    }
    private class MyView extends View 
    {
        private Paint mPaint;
        public MyView(Context context) 
        {
            super(context);
            mPaint = new Paint();
            mPaint.setColor(Color.YELLOW); 
            mPaint.setTextSize(12);
        }
        public void onDraw(Canvas canvas) 
        {
            float x = 10;
            float y = 20;
            canvas.drawText(String.valueOf(azimuth_angle), x, y, mPaint );
            azimuth_angle--;
        }
        public boolean onTouchEvent(MotionEvent event) 
        {
            invalidate();//But this can work
            return true;
        }
    }
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // TODO Auto-generated method stub
    }
    public void onSensorChanged(SensorEvent event) {
        // TODO Auto-generated method stub
         if(event.sensor.getType() == Sensor.TYPE_ORIENTATION)
         {
             azimuth_angle = event.values[0];
             mView.invalidate();//it doesnt work
         } 
    }
}