我尝试使用 Java 1.6 中的 Swing 创建一个包含 3 个元素的 JFrame:一个在页面的开头，第二个在同一行，左边有一些间距，第三个在新行。但是在几次尝试后都失败了:
BorderLayout.[SOUTH|WEST|EAST|NORTH]
BorderLayout.[LINE_START|LINE_END|AFTER_LINE_END|AFTER_LAST_LINE]
FlowLayout.LEFT
BoxLayout.[X_AXIS|Y_AXIS]
它显示正确的唯一方式是在使用时:
container.add(firstElement, BorderLayout.WEST);
container.add(secondElement, BorderLayout.EAST);
container.add(thirdElement, BorderLayout.SOUTH);
这是我程序的当前版本:
import javax.swing.*;
import java.awt.*;
//import java.awt.event.*;
//import java.lang.reflect.*;
public class MainClass {
public static void main(String[] args) {
JFrame frame = new JFrame("JFrame Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container container = frame.getContentPane();
JTextField field = new JTextField();
JButton button = new JButton("Enter");
JTextArea outputarea = new JTextArea("Outputtext before input.");
outputarea.setEditable(false);
container.add(field, BoxLayout.X_AXIS);
container.add(button, BoxLayout.X_AXIS);
container.add(outputarea, BoxLayout.Y_AXIS);
field.setPreferredSize(new Dimension(600, 30));
button.setPreferredSize(new Dimension(100, 30));
//button.setMargin(new Insets(0, 10, 0, 0)); //left-margin
outputarea.setPreferredSize(new Dimension(700, 300));
container.setPreferredSize(new Dimension(800, 400));
frame.pack();
frame.setVisible(true);
}
}
虽然我想实现这样的目标:
https://dl.dropboxusercontent.com/u/72032667/JFrame_Demo.html
来源:
<!doctype html>
<html lang="en">
<head>
<title>JFrame Demo</title>
<style type="text/css">
body {width:800px; min-height:400px;}
* {float:left; margin:0; color:inherit;}
#input {width:600px;}
#button {margin-left:10px; background:#AAA; padding:2px 5px; border:1px solid black;}
#textarea {width:700px; height:300px; resize:none; white-space:nowrap;}
</style>
<script type="text/javascript">
function myAction() {
var inputElement = document.getElementById('input');
var outputElement = document.getElementById('textarea');
outputElement.innerHTML = myMethod(inputElement.value);
function myMethod(str) {
// Do something more useful than this:
return "You wrote: "+str;
}
}
</script>
</head>
<body>
<input id="input" />
<a href="#" onclick="myAction()"><p id="button">Enter</p></a>
<br>
<textarea id="textarea" readonly spellcheck="false" warp="off"></textarea>
</body>
</html>
我看过一些例子，他们给 JFrame 的构造函数一个 Component 作为参数来选择布局，但我不明白它是如何工作的。
编辑:我不会接受这 3 个元素的嵌套解决方案。
最佳答案
好的，我知道这不是你想要的答案，抱歉。但我只是想告诉你我的评论是什么意思以及如何去做。这不是一个直接的答案，但也许你会在看到它后改变主意 :P(尤其是关于 setPreferredSize()，因为这不是真正推荐的做法)。这将适用于几乎任何尺寸的帧:
代码:
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class MainClass {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new MainClass();
}
});
}
public MainClass() {
JFrame frame = new JFrame("JFrame Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextArea outputarea = new JTextArea();
outputarea.setBorder(new LineBorder(Color.GRAY));
outputarea.setWrapStyleWord(true);
outputarea.setLineWrap(true);
outputarea.setEditable(false);
JTextField field = new JTextField();
field.setBorder(new CompoundBorder(new EmptyBorder(0, 0, 3, 0), field.getBorder()));
JButton button = new JButton("Enter");
button.setBackground(Color.LIGHT_GRAY);
button.setFocusPainted(false);
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
outputarea.setText("You wrote: " + field.getText());
}
});
// This panel is just needed in order to set a border for the button
// without losing it's margin.
BorderPanel buttonPanel = new BorderPanel();
buttonPanel.setBorder(new CompoundBorder(new EmptyBorder(0, 10, 0, 30), new LineBorder(Color.BLACK)));
buttonPanel.add(button);
BorderPanel northPanel = new BorderPanel();
northPanel.add(field);
northPanel.add(buttonPanel, BorderLayout.EAST);
BorderPanel mainPanel = new BorderPanel();
mainPanel.add(outputarea);
mainPanel.add(northPanel, BorderLayout.NORTH);
frame.setContentPane(mainPanel);
frame.setSize(600, 300);
frame.setVisible(true);
}
public class BorderPanel extends JPanel {
public BorderPanel() {
setLayout(new BorderLayout());
setBackground(Color.WHITE);
}
}
}
最终结果:
关于java - JFrame : How to make a simple layout with linebreak-like behavior?，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33505020/