Colored boxed with letters a la Gmail

Question

I wondered how they are generated and if they are generated everytime I open the app or are stored (cached).

It\'s just a canvas (programmatically) or they use XML?

Answer 1

Building up on @adneal's response, if we want to generate circular icons we can modify the getLetterTile function as follows:

public Bitmap getLetterTile(String displayName, String key, int width, int height, boolean round) {
    final Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    final char firstChar = displayName.charAt(0);

    final Canvas c = mCanvas;
    c.setBitmap(bitmap);

    if (round) {
        Paint paint = new Paint();
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(pickColor(key));
        c.drawCircle(width/2, height/2 , width/2, paint);
    } else {
        c.drawColor(pickColor(key));
    }

    if (isEnglishLetterOrDigit(firstChar)) {
        mFirstChar[0] = Character.toUpperCase(firstChar);
        mPaint.setTextSize(mTileLetterFontSize);
        mPaint.getTextBounds(mFirstChar, 0, 1, mBounds);
        c.drawText(mFirstChar, 0, 1, 0 + width / 2, 0 + height / 2
                + (mBounds.bottom - mBounds.top) / 2, mPaint);
    } else {
        c.drawBitmap(mDefaultBitmap, 0, 0, null);
    }
    return bitmap;
}