Question

如果TextArea通过设置setWrapText(true)包装文本，如何确定行数？行数我指的是用户在整个TextArea包含可滚动内容中可视化的行数。

将\n分割文本或询问段落计数都不起作用，因为包装与实际的行拆分无关。

Answer 1

这是我迄今为止的解决方案，核心原则围绕这样一个事实，即javafx中FontMetrics类返回的行高（略微）偏离Text确定的实际行高。节点，这导致了使用这种类型的节点作为帮助器的基本思想。

使用有效换行文字计算行数

通过使用助手Text节点进行测量，重置和恢复该助手上的包裹宽度并记录高度变化，基本确定实际行高。

计算没有有效换行文字的行

这是最简单的：在这种情况下，paragraphs属性的大小直接对应于行数：

将它们放在一起可能看起来像这样：

  /**
   * Calculates the current amount of rows in the textarea regardless 
   * of "wordWrap" set to {@code true} or {@code false}.
   * 
   * @return the current count of rows; {@code 0} if the count could not be determined
   */
  private int getRowCount() {
    int currentRowCount = 0;
    Text helper = new Text();
    /*
     * Little performance improvement: If "wrapText" is set to false, then the
     * list of paragraphs directly corresponds to the line count, otherwise we need 
     * to get creative...
     */
    if(this.textArea.isWrapText()) {
      // text needs to be on the scene
      Text text = (Text) textArea.lookup(".text");
      if(text == null) {
        return currentRowCount;
      }
      /*
       * Now we just count the paragraphs: If the paragraph size is less
       * than the current wrappingWidth then increment; Otherwise use our
       * Text helper instance to calculate the change in height for the 
       * current paragraph with "wrappingWidth" set to the actual 
       * wrappingWidth of the TextArea text
       */
      helper.setFont(textArea.getFont());
      for (CharSequence paragraph : textArea.getParagraphs()) {
        helper.setText(paragraph.toString());
        Bounds localBounds = helper.getBoundsInLocal();

        double paragraphWidth = localBounds.getWidth();
        if(paragraphWidth > text.getWrappingWidth()) {          
          double oldHeight = localBounds.getHeight();
          // this actually sets the automatic size adjustment into motion...
          helper.setWrappingWidth(text.getWrappingWidth());
          double newHeight = helper.getBoundsInLocal().getHeight();
          // ...and we reset it after computation
          helper.setWrappingWidth(0.0D);

          int paragraphLineCount = Double.valueOf(newHeight / oldHeight).intValue();
          currentRowCount += paragraphLineCount;
        } else {
          currentRowCount += 1;
        }
      }
    } else {
      currentRowCount = textArea.getParagraphs().size();
    }
    return currentRowCount;
  }

希望这有帮助！

确定包装文本的TextArea的行数

1 个答案: