弹出窗口中的 JScrollPane 不会以编程方式向上滚动
我有一个弹出菜单，可在 JScrollPane 的 JPanel 中显示动态创建的自定义 JPanel 对象。弹出菜单向用户显示推荐，最上面的元素是最相关的推荐。我正在使用 JPopupMenu 显示窗口：
JPanelTemplatePopup jptep = new JPanelTemplatePopup();
JPopupMenu popup = new JPopupMenu();
popup.add(jptep);
popup.show(this, 500, 100);
问题是，我无法使 JScrollPane 滚动到最上面的元素以首先显示它。我尝试过：
- .getViewPort().setViewPosition(new 点(0,0));
- .scrollRectToVisible(firstelement.getBounds());
validate() 之前和之后。无论我做什么，当窗口弹出时，滚动窗格总是停留在同一个位置。
我什至怀疑在显示窗口之前发生的操作被忽略了，所以我从类中创建并调用了一个公共方法，以使窗口在显示后向上滚动。一切都没有改变。
请帮助，
埃姆雷
I have a popup menu that displays dynamically created custom JPanel objects in a JPanel in a JScrollPane. The popup menu displays recommendations to the user and the topmost element is the most relevant recommendation. I am using JPopupMenu to display the window:
JPanelTemplatePopup jptep = new JPanelTemplatePopup();
JPopupMenu popup = new JPopupMenu();
popup.add(jptep);
popup.show(this, 500, 100);
The problem is, I can't make the JScrollPane scroll to the topmost element to display it first. I have tried:
- .getViewPort().setViewPosition(new
Point(0,0)); - .scrollRectToVisible(firstelement.getBounds());
before and after validate()s. No matter what I do, when the window pops up, the scroll pane always stays at the same place.
I have even suspected that the operations that took place before displaying the window were ignored, so I created and called a public method from the class to make the window scroll it up after being displayed. Nothing changed.
Please help,
Emre
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是的，好吧，找到了解决方法。
我已将问题范围缩小到自定义 JPanel 对象中的 JEditorPane。其内容由程序动态更新。在生成对象时，我通过 setText 方法设置 JEditorPanes 的内容。通过将文本设置为字符串来更新插入符位置，强制滚动窗格向下滚动。
我刚刚将其插入到构造函数中，问题就解决了：
Yeah, well, found a workaround for this.
I have narrowed the problem down to a JEditorPane that was in the custom JPanel objects. Its contents were dynamically updated by the program. While generating the objects, I was setting JEditorPanes' contents by their setText methods. Updating the caret position by setting the text to a string forced the scroll pane to scroll below.
I just inserted this to the constructor and the problem was fixed: