/**
     * Register a callback to be invoked when this view is clicked. If this view is not
     * clickable, it becomes clickable.
     *
     * @param l The callback that will run
     *
     * @see #setClickable(boolean)
     */
    public void setOnClickListener(OnClickListener l) {
        if (!isClickable()) {
            setClickable(true);
        }
        getListenerInfo().mOnClickListener = l;
    }




View的 setOnClickListener() 会强制性的将 view 设为 clickable, 当然,后面还可以改过来.