java - 按钮未显示在我的 Jframe 中

Question

这个问题已经有答案了:

Why shouldn't I call setVisible(true) before adding components? (2 个回答)

已关闭 7 年前。

除了按钮之外的所有内容都显示在窗口中。我缺少什么吗？这是第一次使用按钮，我不确定出了什么问题。这可能是格式问题。有人可以告诉我 setLocation() 和 setSize() 是否有问题吗？

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.TextField;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class HashString extends JPanel {


    public static void hashString() {
    }

    public void window() {
    JLabel label1 = new JLabel(
            "Enter Your Strings separated by a comma, below. ");
    label1.setHorizontalAlignment(JLabel.CENTER);
    label1.setFont(new Font("Times New Roman", Font.BOLD, 12));
    label1.setVerticalAlignment(JLabel.TOP);

    JTextField field = new JTextField(50);
    field.setVisible(true);
    field.setText("Enter Strings Here");
    field.setSize(300, 251);
    field.setHorizontalAlignment(JTextField.CENTER);
    field.setLocation(135, 60);

    Button btn = new Button("Enter These Values");
    btn.setLocation(240 ,420);
    btn.setSize(100, 100);
    btn.setVisible(true);
    btn.setFont(new Font("Times new roman",Font.BOLD,12));

    JFrame frame = new JFrame("Test1");
    frame.add(new HashString());
    frame.add(btn);
    frame.setVisible(true);
    frame.add(field);
    frame.setLocationRelativeTo(null);
    frame.add(label1);
    frame.setSize(600, 450);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}

Answer 1

我认为你应该改变你构建程序的方式。您应该简单地使用布局管理器(如 BorderLayout)，而不是在 JFrame 内手动放置每个位置，它可以在此处轻松实现。

此外，您应该始终处理 EventQueue 中的所有内容，而不是任何其他线程。此外，不建议混合搭配 AWT 组件(如 Button)和 Swing 组件(如 JButton)。虽然它比以前好得多(如 Java 1.6)，但它仍然会出现一些问题。

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class HashString {   // It seems that this isn't a JPanel. Rather, it is an application.

    JFrame frame;

    public void initialise() {

        frame = new JFrame("Test 1");   // You can create the frame of the application here and set title

        frame.setLocation(200, 200);
        frame.setSize(300, 300);

        JPanel contentPanel = new JPanel();     // To allow a border to be set, I've declared a content panel inside the
                                                // frame.
        contentPanel.setBorder(new EmptyBorder(5, 5, 5, 5));    // This sets a border to make everything look nice
        contentPanel.setLayout(new BorderLayout(5, 5)); // This creates the BorderLayout, which manages the layout of
                                                        // the components easily
        frame.setContentPane(contentPanel);

        JLabel instructionsLabel = new JLabel("Enter Your Strings separated by a comma, below. ");
        instructionsLabel.setFont(new Font("Times New Roman", Font.BOLD, 12));
        contentPanel.add(instructionsLabel, BorderLayout.NORTH);    // BorderLayout.NORTH tells the layout manager where
                                                                    // to put the component.

        JTextField txtField = new JTextField();
        txtField.setText("Enter Strings Here");
        contentPanel.add(txtField, BorderLayout.CENTER);

        JButton btn = new JButton("Enter These Values");
        btn.setFont(new Font("Times new roman", Font.BOLD, 12));
        btn.addActionListener(new ActionListener() {
            @Override public void actionPerformed(ActionEvent e) {
                // Call whatever method that you want to call when this is relevant. Set textField and other variables
                // here. You can do things like 'txtField.setText( methodOperationOnString ( txtField.getText() ) )' or
                // something of the like.
            }
        });
        contentPanel.add(btn, BorderLayout.SOUTH);

        frame.setVisible(true);

    }

    public static void main(String[] args) {
        // This tells it to create the entire thing on the GUI thread
        EventQueue.invokeLater(new Runnable() {
            @Override public void run() {
                HashString b = new HashString();
                b.initialise();
            }
        });
    }
}