java - 将 JPanel 添加到 JFrame

Question

我有一个将 JPanel 添加到 JFrame 的程序:

public class Test{

    Test2 test = new Test2();
    JFrame frame = new JFrame();

    Test(){

    ...
    frame.setLayout(new BorderLayout());
    frame.add(test, BorderLayout.CENTER);
    ...

    }

    //main

    ...

    }

    public class Test2{

    JPanel test2 = new JPanel();

    Test2(){

    ...

    }

}

我收到一条错误消息，要求我将“面板”类型更改为“组件”。我要修复这个错误吗？它要我做:Component panel = new Component();

Answer 1

public class Test{

Test2 test = new Test2();
JFrame frame = new JFrame();

Test(){
...
frame.setLayout(new BorderLayout());
frame.add(test, BorderLayout.CENTER);
...
}

//main
...
}

//public class Test2{
public class Test2 extends JPanel {

//JPanel test2 = new JPanel();

Test2(){
...
}