无法在JScrollPane中看到组件 [英] Can't see components in JScrollPane

问题描述

我正在使用JScrollPane来保存大面积文本的JTextArea。我将TextArea直接添加到JFrame，它工作正常。但我将它添加到滚动窗格并添加滚动窗格，我没有看到textarea。这是我的SSCCE：

  public class foo extends JFrame {
 // gui elements 
 JTextArea chatMonitor = new的JTextArea（）; 
 
 JScrollPane textPane = new JScrollPane（）; 
 
 ChatFrame（最终String昵称，最终String登录，final String server，final String channel）{
 setSize（500,500）; 
 chatMonitor.setEditable（false）; 
 chatMonitor.setVisible（true）; 
 textPane.add（chatMonitor）; 
 textPane.setAutoscrolls（true）; 
 textPane.setHorizo​​ntalScrollBarPolicy（JScrollPane.HORIZONTAL_SCROLLBAR_​​AS_NEEDED）; 
 textPane.setVisible（true）; 
 add（textPane）; 
} 
} 
  

解决方案

假设 textPane 是一个 JScrollPane ，你永远不应该向它添加组件。

而是使用获取更多详细信息

I'm using a JScrollPane to hold a JTextArea for a large area of text. I add the TextArea directly to the JFrame, it works fine. But I add it to the scrollpane and add the scrollpane, I don't see the textarea. Here's my SSCCE:

public class foo extends JFrame{
    //gui elements
JTextArea chatMonitor = new JTextArea();

JScrollPane textPane = new JScrollPane();

ChatFrame(final String nickname, final String login, final String server, final String channel){
    setSize(500,500);
    chatMonitor.setEditable(false);
    chatMonitor.setVisible(true);
    textPane.add(chatMonitor);
    textPane.setAutoscrolls(true);
    textPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    textPane.setVisible(true);
    add(textPane);
}
}

解决方案

Assuming textPane is a JScrollPane, you should never be adding components to it.

Instead use JScrollPane#setViewportView(Component)

JScrollPane is made of a number components which work together to provide you the functionality required to make the component scrollable...

JScrollPane has a JViewport, which is used to contain the component you want to be scrolled. You need to "apply" the component to the view.

Take a closer look at How to use Scroll Panes for more details

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