CompassView.java

package org.wheelmap.android.view;

import org.wheelmap.android.online.R;

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

public class CompassView extends View {

    private float direction = 0;

    private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

    private boolean firstDraw;

    private int mColor;

    private final static int DEFAULT_COLOR_RES = R.color.dark_grey_one;

    private static String TAG = CompassView.TAG;

    public void setName(String name) {
        this.name = name;
    }

    private String name;

    public CompassView(Context context) {
        super(context);
        init();
    }

    public CompassView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initAttributes(attrs);
        init();
    }

    public CompassView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initAttributes(attrs);
        init();
    }

    private void initAttributes(AttributeSet attrs) {
        TypedArray a = getContext().obtainStyledAttributes(attrs,
                R.styleable.CompassView);
        try {

            mColor = a.getColor(R.styleable.CompassView_compassview_color, getContext()
                    .getResources().getColor(DEFAULT_COLOR_RES));
        } finally {
            a.recycle();
        }
    }

    private void init() {
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(2);
        paint.setColor(mColor);
        firstDraw = true;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
                MeasureSpec.getSize(heightMeasureSpec));
    }

    @Override
    protected void onDraw(Canvas canvas) {

        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);
        if (!firstDraw) {
            //Log.d("CompassView","id: " + name + " ---- d: " + direction);
            canvas.drawLine(
                    cxCompass,
                    cyCompass,
                    (float) (cxCompass + radiusCompass
                            * Math.cos(Math.toRadians(direction))),
                    (float) (cyCompass - radiusCompass
                            * Math.sin(Math.toRadians(direction))), paint);
        }

    }

    public void updateDirection(float dir) {
        firstDraw = false;
        direction = dir;
        invalidate();

        //Log.d("CompassView", "-------------------- new -----------------");
    }

}