java gui背景颜色没有覆盖整个页面

Question

当我在java中创建我的图形用户界面时，我将背景颜色设置为黑色，并且在我的图形用户界面的最右侧和最底部部分似乎有一条白色的像素线。然而，当我调整这个图形用户界面的大小时，这种感觉消失了，图形用户界面完全变黑了。有谁知道为什么会发生这种情况？我需要我的 gui 将 resizeable 设置为 false，因此调整 gui 大小来解决此问题将不起作用。

package JavaQuizGameTut;
import java.awt.ActiveEvent.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.*;
import javax.swing.*;
public class Quiz implements ActionListener{

    String[] questions = {
            "Which company created Java?", 
            "What year was Java created?",
            "What was java originally called?",
            "Who was credited for making java?"
        };
    String[][] options = {{"Sun Microsystems", "Starbucks", "Microsoft", "Alphabet"},
                        {"1989", "1996", "1972", "1492"},
                        {"Apple", "Latte", "Oak", "Koffing"},
                        {"Steve Jobs", "Bill Gates", "James Gosling", "Mark Zuckerburg"}
                        };
    char[] answers = {'A', 'B', 'C', 'C'};
    char guess;
    char answer;
    int index;
    int correct_guesses = 0;
    int total_questions = questions.length;
    int result;
    int seconds;

    JFrame frame = new JFrame();
    JTextField textfield = new JTextField();
    JTextArea textarea = new JTextArea();
    JButton buttonA = new JButton();
    JButton buttonB = new JButton();
    JButton buttonC = new JButton();
    JButton buttonD = new JButton();
    JLabel answer_labelA = new JLabel();
    JLabel answer_labelB = new JLabel();
    JLabel answer_labelC = new JLabel();
    JLabel answer_labelD = new JLabel();
    JLabel time_label = new JLabel();
    JLabel seconds_left = new JLabel();
    JTextField number_right = new JTextField();
    JTextField percentage = new JTextField();




    public Quiz() {
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(650, 650);
        frame.getContentPane().setBackground(new Color(50, 50, 50));
        frame.setLayout(null);
        // frame.setResizable(false);

        textfield.setBounds(0, 0, 650, 50);
        textfield.setBackground(new Color(25,25, 25));
        textfield.setForeground(new Color(25, 255, 0));
        textfield.setFont(new Font("Ink Free", Font.PLAIN, 30));
        textfield.setBorder(BorderFactory.createBevelBorder(1));
        textfield.setHorizontalAlignment(JTextField.CENTER);
        textfield.setEditable(false);

        frame.add(textfield);



        frame.setVisible(true);

    }
    public void nextQuestion() {

    }
    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub

    }
    public void displayAnswer() {

    }
    public void results() {

    }
}

Answer 1

背景颜色确实覆盖了整个框架，只是您在其上方看到灰色条的原因是您在其顶部放置了一个文本字段并将其背景颜色设置为灰色。就像这里一样:

textfield.setBounds(0, 0, 650, 50);
textfield.setBackground(new Color(25,25, 25));

尝试更改文本字段的颜色或暂时对其进行注释，您将看到整个框架为黑色。

如果没有任何办法修复它，那么您的系统有问题，因为它在我的系统中运行良好。

您可以尝试在另一个系统中运行它。