BadgeDrawable.java 文件源码

@Override
public void draw(Canvas canvas) {
    if (!mWillDraw) {
        return;
    }

    Rect bounds = getBounds();
    float width = 50;
    float height = 50;

    // Position the badge in the top-right quadrant of the icon.
    float radius = ((Math.min(width, height) / 2) - 1) / 2;
    float centerX = width - radius - 1;
    float centerY = radius + 1;

    // Draw badge circle.
    canvas.drawCircle(centerX, centerY, radius, mBadgePaint);

    // Draw badge count text inside the circle.
    mTextPaint.getTextBounds(mCount, 0, mCount.length(), mTxtRect);
    float textHeight = mTxtRect.bottom - mTxtRect.top;
    float textY = centerY + (textHeight / 2f);
    canvas.drawText(mCount, centerX, textY, mTextPaint);
}