java - 我如何知道未修饰的 JFrame 已完全绘制在屏幕上？

Question

我有一个像这样的简单代码:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Test {
    public static void main(String[] args) {
        Rectangle maximizeRectangle=GraphicsEnvironment.getLocalGraphicsEnvironment().
        getMaximumWindowBounds();
        JFrame frame1 = new JFrame();
        JFrame frame2 = new JFrame();

        //frame1
        frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame1.setUndecorated(true);
        frame1.setBounds(maximizeRectangle);
        JPanel cp1 = new JPanel();
        cp1.setBackground(new Color(200, 200, 200));
        JButton but1 = new JButton("I'm frame 1");
        cp1.add(but1);
        ActionListener ac1 = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                frame2.setVisible(true);
                //here is my question:
                //how can I know when frame2 has been fully painted? and then I can 
                //set visibility of frame1 to false to avoid flickering
                frame1.setVisible(false);
            }
        };
        but1.addActionListener(ac1);
        frame1.setContentPane(cp1);

        //frame2
        frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame2.setUndecorated(true);
        frame2.setBounds(maximizeRectangle);
        JPanel cp2 = new JPanel();
        cp2.setBackground(new Color(200, 200, 200));
        JButton but2 = new JButton("I'm frame 2");
        cp2.add(but2);
        ActionListener ac2 = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                frame1.setVisible(true);
                //here is my question:
                //how can I know when frame1 has been fully painted? and then I can 
                //set visibility of frame2 to false to avoid flickering
                frame2.setVisible(false);
            }
        };
        but2.addActionListener(ac2);
        frame2.setContentPane(cp2);

        frame1.setVisible(true);
    }
}

当我按下按钮时，我可以看到闪烁(桌面背景)。在将另一个 JFrame 的可见性设置为 false 之前，如何知道 JFrame 已完全绘制在屏幕上？

当我按下按钮时，我可以看到闪烁(桌面背景)。在将另一个 JFrame 的可见性设置为 false 之前，如何知道 JFrame 已完全绘制在屏幕上？

我无法使用计时器解决方案!

非常感谢

Answer 1

我重写了您的示例，没有第二帧和相应的闪烁。正如我在评论中已经提到的，您应该使用 CardLayout 而不是第二帧。

import java.awt.CardLayout;
import java.awt.Color;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
    private static final String FRAME1 = "frame1";

    private static final String FRAME2 = "frame2";

    public static void main(String[] args) {
        SwingUtilities.invokeLater(Test::startUp);
    }

    private static void startUp() {
        Rectangle maximizeRectangle = GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds();
        JFrame frame1 = new JFrame();
        CardLayout cl = new CardLayout();
        frame1.setLayout(cl);

        // frame1
        frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame1.setUndecorated(true);
        frame1.setBounds(maximizeRectangle);
        JPanel cp1 = new JPanel();
        cp1.setBackground(new Color(200, 200, 200));
        JButton but1 = new JButton("I'm frame 1");
        cp1.add(but1);
        ActionListener ac1 = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                cl.show(frame1.getContentPane(), FRAME2);
            }
        };
        but1.addActionListener(ac1);
        frame1.add(cp1, FRAME1);

        // frame2
        JPanel cp2 = new JPanel();
        cp2.setBackground(new Color(200, 200, 200));
        JButton but2 = new JButton("I'm frame 2");
        cp2.add(but2);
        ActionListener ac2 = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                cl.show(frame1.getContentPane(), FRAME1);
            }
        };
        but2.addActionListener(ac2);
        frame1.add(cp2, FRAME2);

        frame1.setVisible(true);
    }
}