[项目总结]怎么获取TextView行数，为什么TextView获取行数为0？

final TextView textView = new TextView(this);
        ViewTreeObserver viewTreeObserver = textView.getViewTreeObserver();
        viewTreeObserver.addOnPreDrawListener(new OnPreDrawListener() {
            boolean flag = true;
            @Override
            public boolean onPreDraw() {
                if(flag){
                    int lineCount = textView.getLineCount();
                    flag = false;
                }
                return false;
            }
        });