JFrame 对象仅在鼠标悬停时显示

Question

我正在尝试从头开始构建自己的计算器。 当我像现在这样运行我的程序时，一些按钮不会出现，直到我将光标悬停在它们上方，我的界限都被搞砸了。但是，当我将 window.setVisible(true); 移动到构造函数的开头时，所有对象的每个边界都已正确放置，但 all 我的对象仅在鼠标悬停时显示。

package guitest;

import java.awt.Color;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;    
import static javax.swing.JFrame.*;

public class Frame implements ActionListener{  


public static int Calculator(int n1, int n2){
    
    return n1 + n2;
}

JTextField num1,num2,ans;
JButton calculate, add, sub, pro, div;
JPanel textFields, actions;

Frame(){
    //Window is being created.
    JFrame window = new JFrame("Calculator");
    window.setDefaultCloseOperation(EXIT_ON_CLOSE);
    window.setResizable(false);
    window.setSize(400, 400);
    
    //Creating panel
    textFields = new JPanel();
    actions = new JPanel();
    
    //Adjusting JPanel
    textFields.setBounds(0, 0, 240, 400);
    actions.setBounds(240, 0, 160, 400);
    
    
    //Creating textfields.
    num1 = new JTextField("Number 1");
    num2 = new JTextField("Number 2");
    ans = new JTextField("Answer");
    ans.setEditable(false);
    
    //Creating calculate button.
    calculate = new JButton("Calclulate");
    add = new JButton("+");
    sub = new JButton("-");
    pro = new JButton("*");
    div = new JButton("/");
    
    //adjusting TextFields to my window
    num1.setBounds(30, 20, 200, 20);
    num2.setBounds(30, 60, 200, 20);
    ans.setBounds(30,100,200,20);
    

    
    //adjusting Buttons to my window
    calculate.setBounds(30, 140, 90, 30);
    
    add.setBounds(20, 20, 50, 50);
    sub.setBounds(75, 20, 50, 50);
    pro.setBounds(20, 75, 50, 50);
    div.setBounds(75, 75, 50, 50);
    
    calculate.addActionListener(this);
    
    //adding to my window
    textFields.add(num1);textFields.add(num2);textFields.add(ans);textFields.add(calculate);
    actions.add(add);actions.add(sub);actions.add(pro);actions.add(div);
    window.add(textFields);window.add(actions);
    
    
    window.setVisible(true);

    
    //Setting everything visible
    //textFields.setVisible(true);actions.setVisible(true);
    //num1.setVisible(true);num2.setVisible(true);ans.setVisible(true);
    //calculate.setVisible(true);add.setVisible(true);sub.setVisible(true);pro.setVisible(true);div.setVisible(true);

    
}

public void actionPerformed(ActionEvent e){
    String n1 = num1.getText();
    String n2 = num2.getText();
    int a = Integer.parseInt(n1);
    int b = Integer.parseInt(n2);
    
    int c;
    c = Calculator(a,b);
    
    String result = String.valueOf(c);
    ans.setText(result);
    
}

public static void main(String[] args) { 
    new Frame();
    
}  


} 

when window.setVisible(true); is in the bottom.

when window.setVisible(true); is at the top.

How it is supposed to look.（我手动将鼠标悬停在所有对象上。）

Answer 1

我更改了您的代码并使用布局而不是 setBouds()。
Swing 提供了不同的 LayoutManager，它们用于以特定方式排列组件。以下类用于表示 Swing 中的布局管理器：

1) java.awt.BorderLayout
2) java.awt.FlowLayout
3) java.awt.GridLayout
4) java.awt.CardLayout
5) java.awt.GridBagLayout
6) javax.swing.BoxLayout
7) javax.swing.GroupLayout
8) javax.swing.ScrollPaneLayout
9) javax.swing.SpringLayout etc.

他们每个人都会按特定顺序排列您的组件，您可以在此处阅读更多信息 (more details...)

public class Frame implements ActionListener {

    public static int Calculator(int n1, int n2) {

        return n1 + n2;
    }

    JTextField num1, num2, ans;
    JButton calculate, add, sub, pro, div;
    JPanel textFields, actions;

    Frame() {
        // Window is being created.
        JFrame window = new JFrame("Calculator");
        window.setDefaultCloseOperation(EXIT_ON_CLOSE);
        window.setResizable(false);
        window.setSize(400, 400);
        window.setLayout(new BorderLayout());
        // Creating panel

        // Creating textfields.
        num1 = new JTextField("Number 1");
        num2 = new JTextField("Number 2");
        ans = new JTextField("Answer");
        ans.setEditable(false);

        // Creating calculate button.
        calculate = new JButton("Calclulate");
        add = new JButton("+");
        sub = new JButton("-");
        pro = new JButton("*");
        div = new JButton("/");

        calculate.addActionListener(this);

        textFields = new JPanel();
        actions = new JPanel();

        GridLayout txtBox = new GridLayout(4, 1);
        txtBox.setVgap(20);
        textFields.setLayout(txtBox);
        
        GridLayout actionBox = new GridLayout(2, 2);
        actions.setLayout(actionBox);
        actions.setPreferredSize(new Dimension(100, 100));
        
        // adding to my window
        textFields.add(num1);
        textFields.add(num2);
        textFields.add(ans);
        textFields.add(calculate);
        actions.add(add);
        actions.add(sub);
        actions.add(pro);
        actions.add(div);
        
        window.setLayout(new FlowLayout());
        
        window.add(textFields);
        window.add(actions);

        window.setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        String n1 = num1.getText();
        String n2 = num2.getText();
        int a = Integer.parseInt(n1);
        int b = Integer.parseInt(n2);

        int c;
        c = Calculator(a, b);

        String result = String.valueOf(c);
        ans.setText(result);

    }

    public static void main(String[] args) {
        new Frame();

    }
}