AVLoadingIndicatorView.java 文件源码

void drawTrack(Canvas canvas) {
    final Drawable d = mIndicator;
    if (d != null) {
        // Translate canvas so a indeterminate circular progress bar with padding
        // rotates properly in its animation
        final int saveCount = canvas.save();

        canvas.translate(getPaddingLeft(), getPaddingTop());

        d.draw(canvas);
        canvas.restoreToCount(saveCount);

        if (mShouldStartAnimationDrawable && d instanceof Animatable) {
            ((Animatable) d).start();
            mShouldStartAnimationDrawable = false;
        }
    }
}