gistfile1.java

package robotograph;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.util.AttributeSet;
import android.widget.ImageView;

public class CountImageView extends ImageView {

    private Paint mCirclePaint;
    private Paint mTextPaint;
    private int mRadius = 0;
    
    private Bitmap mXferBitmap;
    private Canvas mXferCanvas;
    
    private String mText = "150";

    public CountImageView(Context context) {
        super(context);

        initView();
    }

    public CountImageView(Context context, AttributeSet attrs) {
        super(context, attrs);

        initView();
    }

    public CountImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        initView();
    }

    private void initView() {
    	/*
    	 * Here we are initializing paintings for further use in
    	 * onDraw method.
    	 */
    	
    	/*
    	 * We are using anti-alias (AA) to draw smooth shapes. Without
    	 * AA there will be noises on edges of text or circle.
    	 */
    	mCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    	mCirclePaint.setStyle(Paint.Style.FILL);
    	mCirclePaint.setColor(0x88ffffff);	//hardcoded - move this to XML
    	
        mTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mTextPaint.setColor(Color.BLACK);
        mTextPaint.setTextAlign(Paint.Align.CENTER);
        
        /*
         * We are using Porter-Duff Xfer mode CLEAR, to "erase"
         * area under text on our translucent-white circle.
         */
        mTextPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
    }
    
    public void setText(String text) {
    	mText = text;
    }
    
    public String getText() {
    	return mText;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        
        final int width = getMeasuredWidth();
        final int height = getMeasuredHeight();
        
        /*
         * Create bitmap for working with Xfer paintings
         */
        if(mXferBitmap == null || mXferBitmap.getWidth() != width
        		|| mXferBitmap.getHeight() != height) {
        	
        	if(mXferBitmap != null) {
        		/*
        		 * Don't forget to cleanup, if we don't need
        		 * bitmap anymore
        		 */
        		mXferBitmap.recycle();
        	}
        	
        	mXferBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        	mXferCanvas = new Canvas(mXferBitmap);
        }
    }
    
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    	super.onSizeChanged(w, h, oldw, oldh);
    	
    	mRadius = w > h ? h/2 : w/2;
    	mRadius *= 0.95;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        final int width = getWidth();
        final int height = getHeight();
        
        mTextPaint.setTextSize(mRadius);
        
        mXferCanvas.drawCircle(width/2, height/2, mRadius, mCirclePaint);
        mXferCanvas.drawText(mText, width/2, height/2 - (mTextPaint.descent() + mTextPaint.ascent())/2, mTextPaint);
        
        canvas.drawBitmap(mXferBitmap, 0, 0, null);
    }
}