JTextField只显示了一个带有GridBagLayout的狭缝，我为类似问题找到的解决方案不起作用

Question

所以有一个JFrame，它包含两个JPanel和一个使用GridBagLayout的按钮。但问题在于同样使用网格布局的面板。JPanel p_addIng有一个3x2网格，第一列中有两个JTextField，第一列的大小很好，但第二列太薄了。

前面有一些免责声明：ing代表配料，gbc代表GridBagConstraints，所有带有b_var的东西都意味着它是一个swing组件b=JButton，tf=JTextField，p=JPanel，cb=JCombobox。

因为其他帖子，我已经尝试过了：gbc_addIng.fill=GridBagConstraint。HORIZONTAL；gbc_addIng.weightx=1；我还看到了使用pack（）方法的地方，但这是针对JFrame的，没有做任何事情来解决这个问题。这是代码：

//making a new panel
//initializing the new Panel
p_addIng = new JPanel();
p_addIng.setName("Adding an Ingredient");
p_addIng.setPreferredSize(ingPanelDim);
p_addIng.setLayout(new GridBagLayout());
GridBagConstraints gbc_ing = new GridBagConstraints(0, 0, 1, 1, 1, 0,
                                                    GridBagConstraints.CENTER, GridBagConstraints.BOTH
                                                    new Insets(0,0,0,0),10, 10);

//the components of the panel
//TextField to set the name of the Ingredient
gbc_ing.gridx = 0; //the position of the component on the panel
gbc_ing.gridy = 0;
tf_ingName = new JTextField();
tf_ingName.setPreferredSize(new Dimension(ingPanelDim.width / 2, ingPanelDim.height/2));
tf_ingName.addActionListener(this);
p_addIng.add(tf_ingName, gbc_ing); //adding the component to the Panel
//endOfTextFieldIngName
gbc_ing.gridx = 1;
gbc_ing.gridy = 0;
//button to add the ingredient
tf_amnt = new JTextField("Choose amount");
tf_amnt.setPreferredSize(new Dimension(ingPanelDim.width/4, ingPanelDim.height/2));
tf_amnt.addActionListener(this);
p_addIng.add(tf_amnt, gbc_ing);
//endOfButtonToAddIng
//button to add the ingredient
gbc_ing.gridx = 2;
gbc_ing.gridy = 0;
UnitOfMeasurement[] un = {UnitOfMeasurement.g, UnitOfMeasurement.kg, UnitOfMeasurement.Stück, UnitOfMeasurement.L, UnitOfMeasurement.ml, UnitOfMeasurement.cm};
cb_measurement = new JComboBox<UnitOfMeasurement>(un);
cb_measurement.setPreferredSize(new Dimension(ingPanelDim.width/4, ingPanelDim.height/2));
cb_measurement.addActionListener(this);
p_addIng.add(cb_measurement, gbc_ing);
//endOfButtonToAddIng
//button to add the ingredient
gbc_ing.gridx = 0;
gbc_ing.gridy = 1;
b_addIng = new JButton("Add Ingredient");
b_addIng.setPreferredSize(new Dimension(ingPanelDim.width/2, ingPanelDim.height/2));
b_addIng.addActionListener(this);
p_addIng.add(b_addIng, gbc_ing);
//endOfButtonToAddIng
//button to remove the ingredient
gbc_ing.gridx = 2;
gbc_ing.gridy = 1;
b_removeIng = new JButton("Remove Ingredient");
b_removeIng.setPreferredSize(new Dimension(ingPanelDim.width/2, ingPanelDim.height/2));
b_removeIng.addActionListener(this);
p_addIng.add(b_removeIng, gbc_ing);
//endOfButtonToRemoveIng
//
frame.pack();
frame.add(p_addIng,gbc_frame);
//

这里，正如所希望的，是全功能类唯一缺少的是枚举UnitOf测量，其中包含cb_meausrement列表中所示的元素：

package WindowDesign;

import Food.UnitOfMeasurement;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;

public class StartingWindow implements ActionListener {

    //window dimension
    private static final int WIDTH = 500;
    private static final int HEIGHT = 200;
    //

    //the JFrame
    private JFrame frame;
    //JComponents
    //adding an Ingredient
    private JPanel p_addIng;
    private Dimension ingPanelDim = new Dimension(WIDTH/2, HEIGHT/2);
    private JButton b_addIng; //a button to add an Ingredient
    private JButton b_removeIng;
    private JTextField tf_ingName;
    private JTextField tf_amnt;
    private JComboBox<UnitOfMeasurement> cb_measurement;
    //

    //adding a Recipe
    private JPanel p_addRecipe;
    private JButton b_addRecipe;    // add a Recipe to the list of Recipes
    private JButton b_removeRecipe;
    private JButton b_buildRecipe;
    private JButton b_clearRecipe;
    private JTextField tf_recipeName;
    private JTextField tf_ingredient;
    private JComboBox<UnitOfMeasurement> cb_measurementR;
    //

    //

    private JButton b_findCombination; //find the right combination of things to buy
    private JButton b_exit; //exit the program

    public StartingWindow(String name) {
        frame = new JFrame(name);
        frame.setLayout(new GridBagLayout());
        //constraints
        GridBagConstraints gbc_frame = new GridBagConstraints();
        frame.setSize(WIDTH, HEIGHT);
        frame.setBackground(Color.LIGHT_GRAY);
        gbc_frame.ipadx = 10;
        gbc_frame.ipady = 10;
        gbc_frame.weightx = 1;
        gbc_frame.fill = GridBagConstraints.BOTH;
        //Adding the Panels
        gbc_frame.gridx = 0;
        gbc_frame.gridy = 0;
        implementIngredientPanel(gbc_frame);

        gbc_frame.gridx += 1;
        gbc_frame.gridy = 0;
        implementRecipePanel(gbc_frame);
        //

        gbc_frame.gridx = 0;
        gbc_frame.gridy = 1;
        implementStartingPanel(gbc_frame);

        /*



        b_exit = new JButton("exit");
        b_exit.addActionListener(this);

         */

        /*
        frame.add(b_findCombination);
        frame.add(b_addIng);
        frame.add(b_addRecipe);
        frame.add(b_exit);
         */

        frame.setResizable(false);
        frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
        frame.requestFocus();
        frame.setLocationRelativeTo(null);
        frame.pack();
        frame.setVisible(true);

    }
    //helper function to organize code
    private void implementIngredientPanel(GridBagConstraints gbc_frame){
        //making a new panel
        //initializing the new Panel
        p_addIng = new JPanel();
        p_addIng.setName("Adding an Ingredient");
        p_addIng.setPreferredSize(ingPanelDim);
        p_addIng.setLayout(new GridBagLayout());
        GridBagConstraints gbc_ing = new GridBagConstraints(0, 0, 1, 1, 1, 0,
                                                            GridBagConstraints.CENTER, GridBagConstraints.BOTH,
                                                            new Insets(0,0,0,0),10, 10);

        //the components of the panel
        //TextField to set the name of the Ingredient
        gbc_ing.gridx = 0; //the position of the component on the panel
        gbc_ing.gridy = 0;
        tf_ingName = new JTextField();
        tf_ingName.setPreferredSize(new Dimension(ingPanelDim.width / 2, ingPanelDim.height/2));
        tf_ingName.addActionListener(this);
        p_addIng.add(tf_ingName, gbc_ing); //adding the component to the Panel
        //endOfTextFieldIngName
        gbc_ing.gridx = 1;
        gbc_ing.gridy = 0;
        //button to add the ingredient
        tf_amnt = new JTextField("Choose amount");
        tf_amnt.setPreferredSize(new Dimension(ingPanelDim.width/4, ingPanelDim.height/2));
        tf_amnt.addActionListener(this);
        p_addIng.add(tf_amnt, gbc_ing);
        //endOfButtonToAddIng
        //button to add the ingredient
        gbc_ing.gridx = 2;
        gbc_ing.gridy = 0;
        UnitOfMeasurement[] un = {UnitOfMeasurement.g, UnitOfMeasurement.kg, UnitOfMeasurement.Stück, UnitOfMeasurement.L, UnitOfMeasurement.ml, UnitOfMeasurement.cm};
        cb_measurement = new JComboBox<UnitOfMeasurement>(un);
        cb_measurement.setPreferredSize(new Dimension(ingPanelDim.width/4, ingPanelDim.height/2));
        cb_measurement.addActionListener(this);
        p_addIng.add(cb_measurement, gbc_ing);
        //endOfButtonToAddIng
        //button to add the ingredient
        gbc_ing.gridx = 0;
        gbc_ing.gridy = 1;
        b_addIng = new JButton("Add Ingredient");
        b_addIng.setPreferredSize(new Dimension(ingPanelDim.width/2, ingPanelDim.height/2));
        b_addIng.addActionListener(this);
        p_addIng.add(b_addIng, gbc_ing);
        //endOfButtonToAddIng
        //button to remove the ingredient
        gbc_ing.gridx = 2;
        gbc_ing.gridy = 1;
        b_removeIng = new JButton("Remove Ingredient");
        b_removeIng.setPreferredSize(new Dimension(ingPanelDim.width/2, ingPanelDim.height/2));
        b_removeIng.addActionListener(this);
        p_addIng.add(b_removeIng, gbc_ing);
        //endOfButtonToRemoveIng
        //
        frame.pack();
        frame.add(p_addIng,gbc_frame);
        //
    }

    private void implementRecipePanel(GridBagConstraints gbc_frame){
        //Adding a Panel to add
        p_addRecipe = new JPanel();
        p_addRecipe.setName("Adding an Ingredient");
        p_addRecipe.setPreferredSize(new Dimension(WIDTH/2, HEIGHT/2));
        p_addRecipe.setLayout(new GridBagLayout());
        GridBagConstraints gbc_recipe = new GridBagConstraints();


        //the components:
        //add Button to Add a Recipe
        b_addRecipe = new JButton("Add Recipe");
        b_addRecipe.addActionListener(this);
        p_addRecipe.add(b_addRecipe, gbc_recipe );
        //

        frame.add(p_addRecipe, gbc_frame);
    }

    private void implementStartingPanel(GridBagConstraints c){
        b_findCombination = new JButton("go shopping!");
        b_findCombination.addActionListener(this);
        c.fill = GridBagConstraints.HORIZONTAL;

        frame.add(b_findCombination, c);
    }

    @Override
    public void actionPerformed(ActionEvent actionEvent) {

    }
}

Answer 1

但是第二个太薄了。

当使用GridBagLayout时，如果组件无法以其首选大小显示，则会以其最小大小显示。JTextField的最小大小是0，所以这就是您看到的。

你有几个不同的问题：

p_addIng.setPreferredSize(ingPanelDim);

您人为地限制了面板的大小，这导致文本字段以其最小大小显示。删除该声明。

此外，您似乎试图让文本字段和组合框填充与按钮相同的空间。如果要执行此操作，则需要让按钮跨越两列：

//gbc_ing.gridx = 2;
gbc_ing.gridx = 1;
gbc_ing.gridwidth = 2;

以上所说的，你似乎错过了使用布局管理器的要点。您不应该尝试设置每个组件的首选大小。定义组件并让布局管理器执行此工作。

例如，在创建JTextField时，您应该使用：

JTextField textField = new JTextField(10);

给出文本字段应该有多大的建议。

Answer 2

这里有一个工作的例子，可能是也可能不是你所要求的...

package stackoverflow;

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

public class IngredientJFrame {

    public static void main(String... args) {

        IngredientJFrame ingredientJFrame = new IngredientJFrame();
        ingredientJFrame.init();
    }

    public void init() {

        JFrame jFrame = new JFrame();

        //making a new panel
        //initializing the new Panel
        JPanel p_addIng = new JPanel();
        p_addIng.setLayout(new GridBagLayout());

        GridBagConstraints gbc_ing = new GridBagConstraints();

        JLabel l_addIng = new JLabel("Add Ingredient");
        gbc_ing.gridx = 0;
        gbc_ing.gridy = 0;
        p_addIng.add(l_addIng, gbc_ing);

        JTextField tf_ingName = new JTextField();
        gbc_ing.gridx = 1;
        gbc_ing.gridy = 0;
        gbc_ing.fill = GridBagConstraints.HORIZONTAL;
        p_addIng.add(tf_ingName, gbc_ing); //adding the component to the Panel

        JLabel tf_amnt = new JLabel("Choose amount");
        gbc_ing.gridx = 0;
        gbc_ing.gridy = 1;
        gbc_ing.fill = GridBagConstraints.NONE;
        p_addIng.add(tf_amnt, gbc_ing);

        JComboBox cb_measurement = new JComboBox();
        gbc_ing.gridx = 1;
        gbc_ing.gridy = 1;
        gbc_ing.fill = GridBagConstraints.HORIZONTAL;
        p_addIng.add(cb_measurement, gbc_ing);

        JButton b_addIng = new JButton("Add Ingredient");
        gbc_ing.gridx = 0;
        gbc_ing.gridy = 2;
        gbc_ing.fill = GridBagConstraints.NONE;
        p_addIng.add(b_addIng, gbc_ing);

        JButton b_removeIng = new JButton("Remove Ingredient");
        gbc_ing.gridx = 1;
        gbc_ing.gridy = 2;
        p_addIng.add(b_removeIng, gbc_ing);

        jFrame.pack();
        jFrame.add(p_addIng);
        jFrame.setSize(500, 500);
        jFrame.setVisible(true);
    }
}

GridBayLayout（GBL）和GridBagConstraint（GBC）功能强大，但很难正确使用，而且容易搞砸。

以下是我如何使用这两个类的一些建议，以及制作基于Swing的UI的其他技巧：

• 一般来说，文本应该使用JLabel显示。这应该有助于你的格式化。
• 一般来说，对于GBL和GBC，我们通常不会在组件上设置实际尺寸。我们允许组件相互反应，并根据需要填充空间。经常使用其他JPanels内部的JPanels来获得我们正在寻找的正确流。
• 我使用GBC的方式很可能不太好，但是我讨厌一遍又一遍地重新制作那个对象。所以，我在我的例子中重用了它，你只需要在重用那个对象时小心，因为很容易设置一个特定的字段，然后忘记“取消设置”它。东西插图。
• 通常，组件有一个匿名的内部类，它实际上执行对组件的监听。