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

 1 final TextView textView = new TextView(this);
 2         ViewTreeObserver viewTreeObserver = textView.getViewTreeObserver();
 3         viewTreeObserver.addOnPreDrawListener(new OnPreDrawListener() {
 4             boolean flag = true;
 5             @Override
 6             public boolean onPreDraw() {
 7                 if(flag){
 8                     int lineCount = textView.getLineCount();
 9                     flag = false;
10                 }
11                 return false;
12             }
13         });