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Ди_
Asked:2020-12-11 06:38:24 +0000 UTC2020-12-11 06:38:24 +0000 UTC

面板未添加到表单中

  • 772
    public class Main   {
        public static void main(String[]args) {
        Window window = new Window();
        window.initializeFrame();
        PanelPhone panelPhone = new PanelPhone();
        panelPhone.initializePanelPhone();
        window.add(panelPhone);

        }
    }


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

public class PanelPhone extends JPanel  {

    JPanel panel;

    public PanelPhone() {
        panel = new JPanel();
        panel.setVisible(true);
    }

    void initializePanelPhone() {
        panel.setLayout(null);
        panel.setBorder(new EtchedBorder());
        panel.setBackground(Color.GRAY);
        panel.setLocation(20, 20);
        panel.setSize(300,200);
        add(panel);

    }
}


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

    public class Window  extends Frame {
        private JFrame frame;

        public Window(){
             frame = new JFrame("Phone");
             frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
             frame.setVisible(true);
        }

        public void initializeFrame() {
            frame.setSize(new Dimension(1000 ,900));
            frame.setLocationRelativeTo(null);
            frame.setLayout(null);

        }

    }
swing

1 个回答

  1. Best Answer

    问题是面板在接收参数之前显示 - 即 您正在显示一个没有背景、没有尺寸的空面板 

        PanelPhone panelPhone = new PanelPhone();//вызыван конструктор, а в нем setVisible()
    panelPhone.initializePanelPhone();//а настройки идут вторым номером - так не сработает

    它是如何工作的（运行）： 

    public class Main {

    public static void main(String[] args) {
        Window window = new Window();
        PanelPhone panelPhone = new PanelPhone();
        window.add(panelPhone);
    }
}

class PanelPhone extends JPanel {

    public PanelPhone() {
        this.setLayout(null);
        this.setBorder(new EtchedBorder());
        this.setBackground(Color.GRAY);
        this.setLocation(20, 20);
        this.setSize(300, 200);
        this.setVisible(true);
    }
}

    class Window extends JFrame {

    public Window() {
        super("Phone");
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setSize(new Dimension(1000, 900));
        this.setLocationRelativeTo(null);
        this.setLayout(null);
        this.setVisible(true);
    }

}

    ps 在我看来，没有必要在已经从必要组件继承的类中创建额外的对象，并将设置写入构造函数，但这更多的是建议而不是修复 - 错误恰好在于调用顺序

    • 0

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