如何在 JScrollPane 中获取（可变）组件的完整大小？

Question

我的代码是这样的：

JFrame frame = new JFrame();

JPanel panel = new JPanel();

JTextPane text = new JTextPane();
text.setPreferredSize(new Dimension(200,260));
text.setContentType("text/html");
text.setEditable(false);
text.setText("some random thing makes this pane bigger than its perferred size");

JScrollPane scroll = new JScrollPane(text);

panel.add(scroll);

frame.add(panel);
frame.setVisible(true);
frame.pack();
frame.validate();

我的问题是我不知道如何获得JTextPane 的实际大小（此处的文本）。我已经尝试了所有getSizes 和getVisibleRects，scroll.getViewport().getViewSize()... 但他们都返回[200,260]。有人可以帮我解决这个问题吗？非常感谢您提供的任何帮助。

编辑：我发现了问题：我的getSizes 请求是在验证框架之前执行的。 我的可运行测试代码：

import java.awt.Dimension;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;

public class Abcd {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    JFrame frame = new JFrame();

    JPanel panel = new JPanel();

    JTextPane text = new JTextPane();
    text.setPreferredSize(new Dimension(150,126));
    text.setContentType("text/html");
    text.setEditable(false);

    //Alicia Vikander's photo. She's cute anw.
    String tmp = "<a href=\"https://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Alicia_Vikander.jpg/220px-Alicia_Vikander.jpg\"><img src=\"https://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Alicia_Vikander.jpg/220px-Alicia_Vikander.jpg\"/></a>";
    //text.setText("asdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sfasdf fssdfsdf sfdsdf sd sdf sf");
    text.setText(tmp);
    JScrollPane scroll = new JScrollPane(text);
    scroll.setPreferredSize(new Dimension(150,126));

    panel.add(scroll);

    frame.add(panel);
    frame.setVisible(true);
    frame.pack();
    frame.validate();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    for (double i = 0; i < 1000; i = i +  0.0001){
        System.out.print(text.getHeight()+"\n");            
        if (text.getHeight()!=123){   //3 pixels for the scrollpane's border i guessed
            System.out.print("i = "+i+", height = "+text.getHeight());
            break;
        }
    }
}

在我的计算机中i 大约是 50 - 100。所以我的新问题是：无论如何我可以尽快获得实际尺寸，但仍确保框架经过验证？ 非常感谢。

Answer 1

我强烈建议你开始使用不同的Layout managers。

如果我对你的代码进行一些修改：

JFrame frame = new JFrame();

final JTextPane text = new JTextPane();
text.setContentType("text/html");
text.setEditable(false);
text.setText("some random thing makes this pane bigger than its perferred size");

final JScrollPane scroll = new JScrollPane(text);
scroll.addComponentListener(new ComponentAdapter()  {
        @Override
        public void componentResized(ComponentEvent e) {
            System.out.println("Size of JScrollPane is: " + scroll.getSize());
            System.out.println("Size of JTextPane is: " + text.getSize());
        }
});

frame.setLayout(new BorderLayout());
frame.add(scroll,BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);

我们将滚动组件的大小调用它的scroll.getSize() 和文本组件的大小调用它的text.getSize()