如何在gridbaglayout中更改网格的最小高度答案

【问题标题】：how to change minimum Height of a grid in gridbag layout如何在gridbaglayout中更改网格的最小高度
【发布时间】：2017-06-18 06:36:19
【问题描述】：

这里我在面板上使用gridbag 布局来添加 5 个排列成 5 行的组件，我希望它们具有不同的高度 like this 但在这样做之后

public void mainpanel3(){

   pupper.setBackground(Color.yellow);
   ptable.setBackground(Color.BLACK);
   lthird.setOpaque(true);
   lthird.setBackground(Color.BLUE);
   tffourth.setBackground(Color.GREEN);
   pfifth.setBackground(Color.WHITE);


   outerp3.setLayout(new GridBagLayout());
   GridBagConstraints c=new GridBagConstraints();


   c.weightx=0.5;
   c.weighty=0.5;
   c.fill=GridBagConstraints.BOTH;

   c.weightx=0.5;
   c.weighty=0.1;
   c.ipady=5;
   c.gridx=0;
   c.gridy=0;       
   outerp3.add(pupper,c);

   c.weightx=0.5;
   c.weighty=0.4;
   c.ipady=20;
   c.gridx=0;
   c.gridy=1;
   outerp3.add(ptable,c);

   c.weightx=0.5;
   c.weighty=0.1;
   c.ipady=5;
   c.gridx=0;
   c.gridy=2;
   outerp3.add(lthird,c);

   c.weightx=0.5;
   c.weighty=0.1;
   c.ipady=5;
   c.gridx=0;
   c.gridy=3;
   outerp3.add(tffourth,c);

   c.weightx=0.5;
   c.weighty=0.1;
   c.ipady=5;
   c.gridx=0;
   c.gridy=4;
   outerp3.add(pfifth,c);

    }

发生这种情况

output

第五个组件（a panel）白色不显示。

关于这个面板的编码只在这个方法中完成，如果你需要任何其他的代码，请告诉我。

【问题讨论】：

所有组件的weighty 值相同。将每个组件分别更改为 0.1、0.5、0.1、0.2 和 0.1，以及 gridheight 属性

标签： java swing layout-manager gridbaglayout

【解决方案1】：

您需要指定weighty 值，尽管weightx 对于每个组件将始终为1.0，因为每个组件的区别仅在于height 而不是width。这是一个工作示例：

import java.awt.*;
import javax.swing.*;

public class GridBagLayoutExample {

    private GridBagConstraints m_GBC;

    public GridBagLayoutExample () {
        m_GBC = new GridBagConstraints ();
        m_GBC.anchor = GridBagConstraints.FIRST_LINE_START;
        m_GBC.fill = GridBagConstraints.BOTH;
    }

    private void displayGUI () {
        JFrame frame = new JFrame ( "GridBagLayout Example" );
        frame.setDefaultCloseOperation ( JFrame.DISPOSE_ON_CLOSE );

        JPanel contentPane = new JPanel ();
        contentPane.setLayout ( new GridBagLayout () );

        addComponent ( contentPane, getPanel (), 0, 0, 1, 1, 1.0, 0.1 );
        addComponent ( contentPane, getPanel (), 0, 1, 1, 5, 1.0, 0.5 );
        addComponent ( contentPane, getPanel (), 0, 6, 1, 1, 1.0, 0.1 );
        addComponent ( contentPane, getPanel (), 0, 7, 1, 2, 1.0, 0.2 );
        addComponent ( contentPane, getPanel (), 0, 9, 1, 1, 1.0, 0.1 );

        frame.setContentPane ( contentPane );
        frame.pack ();
        frame.setLocationByPlatform ( true );
        frame.setVisible ( true );
    }

    private void addComponent ( JComponent contentPane, JComponent component,
                                int x, int y, int gridwidth, int gridheight,
                                double weightx, double weighty ) {
        m_GBC.gridx = x;
        m_GBC.gridy = y;
        m_GBC.gridwidth = gridwidth;
        m_GBC.gridheight = gridheight;
        m_GBC.weightx = weightx;
        m_GBC.weighty = weighty;

        contentPane.add ( component, m_GBC );
    }

    private JPanel getPanel () {
        JPanel panel = new JPanel ();
        panel.setOpaque ( true );
        Color color = new Color ( ( float ) Math.random (), ( float ) Math.random (),
                                ( float ) Math.random (), ( float ) Math.random () );
        panel.setBackground ( color );

        return panel;
    }

    public static void main ( String [] args ) {
        Runnable runnable = new Runnable () {
            @Override
            public void run () {
                new GridBagLayoutExample ().displayGUI ();
            }
        };
        EventQueue.invokeLater ( runnable );
    }
}

输出

【讨论】：