java 如何在 JPanel 上定位/布局组件？
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How to position/lay out components on JPanel?
提问by Bernard
I'm trying to position 5 buttons on a JFrame. Four buttons should be in first row and the fifth one should be in the second row. But here all of the buttons appear in one row and half of the fifth button is out of the panel. By the way if I use frame.pack(); my frame become smaller than what I expected. I don't want to change the size of frame. I want to locate the fifth one in the second row.
我试图在 JFrame 上放置 5 个按钮。四个按钮应该在第一行，第五个应该在第二行。但是这里所有的按钮都出现在一行中，第五个按钮的一半在面板之外。顺便说一下，如果我使用 frame.pack(); 我的框架变得比我预期的要小。我不想改变框架的大小。我想在第二行找到第五个。
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.*;
public class test {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setBounds(100, 100, 529, 300);
frame.getContentPane().setLayout(new GridLayout(1, 0, 0, 0));
JPanel panel = new JPanel();
frame.getContentPane().add(panel);
panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));
JButton btnNewButton_4 = new JButton("New button");
panel.add(btnNewButton_4);
JButton btnNewButton_3 = new JButton("New button");
panel.add(btnNewButton_3);
JButton btnNewButton = new JButton("New button");
panel.add(btnNewButton);
JButton btnNewButton_1 = new JButton("New button");
panel.add(btnNewButton_1);
JButton btnNewButton_2 = new JButton("New button");
panel.add(btnNewButton_2);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
回答by mKorbel
Four buttons should be in first row and the fifth one should be in the second row.
四个按钮应该在第一行，第五个应该在第二行。
standard and booking examples in Oracle tutorial about How to use Layout Managers
use GridLayout (two rows)for JPanel, but all JButtons will have the same dimension
use GridBagLayout, then each of JButtons will have diferrent size or not too
invisible JComponents or empty JLabel can help you in most complicated variations
Oracle 教程中关于如何使用布局管理器的标准和预订示例
对 JPanel使用GridLayout（两行），但所有 JButton 将具有相同的尺寸
使用GridBagLayout，那么每个 JButton 都会有不同的大小
不可见的 JComponents 或空的 JLabel 可以帮助您处理最复杂的变化
回答by Pablo Lozano
You are using a BoxLayout, where components will not wrap (check the API documentation: http://docs.oracle.com/javase/6/docs/api/javax/swing/BoxLayout.html)
您正在使用 BoxLayout，其中组件不会包装（检查 API 文档：http: //docs.oracle.com/javase/6/docs/api/javax/swing/BoxLayout.html）
About the size, try to use panel.setMinimumSize(Dimension d)
关于尺寸，尽量使用 panel.setMinimumSize(Dimension d)
回答by tgkprog
What I do is use null as the layout manager and place the components my self. A manager works well if you want your components to be relayed when the window is resized or you do not know the final size of applet etc
我所做的是使用 null 作为布局管理器并将组件放置在我自己的位置上。如果您希望在调整窗口大小时中继组件或者您不知道小程序的最终大小等，则管理器可以很好地工作
But most of the time that is not true or over kill
但大多数时候这不是真的或过度杀戮
Instead just place the components on a grid by pixel using setBounds(x,y,width,height); Example:
而是使用 setBounds(x,y,width,height) 将组件按像素放置在网格上；例子：
JFrame frame = new JFrame();
frame.setBounds(100, 100, 529, 300);
frame.getContentPane().setLayout(null);//over ride default
Container c = frame.getContentPane();
JButton btnNewButton_4 = new JButton("New button");
c.add(btnNewButton_4);
c.seBounds(4,10,40,25);
JButton btnNewButton_3 = new JButton("New button 3");
c.add(btnNewButton_3);
c.seBounds(40,10,40,25);//...etc
Samples
样品
回答by Erfan
You can also use setBounds(arg1 , arg2 , arg3 , arg4) method. Use this for a better help. Doing Without a Layout Manager (Absolute Positioning)
您还可以使用 setBounds(arg1 , arg2 , arg3 , arg4) 方法。使用它以获得更好的帮助。无需布局管理器（绝对定位）
