从外部类向JPanel添加对象

Hi I am trying to add an object for example a JLabel from a main class to a secondary class that inherits the attributes of a JPanel.I have created a basic example that shows what I was trying to do but it dosen't work.Here is my code:

您好我正在尝试将一个对象(例如JLabel)从主类添加到继承JPanel属性的辅助类。我创建了一个基本示例,显示了我尝试做的但是它不起作用。这里。这里是我的代码:

public class main extends JFrame{


public main(){
    this.setVisible(true);
    this.setSize(600, 600);
    panel nou = new panel(new JLabel("a mers"));
}
public static void main (String[] args){
    new main();
}

}

public class panel extends JPanel{

    public panel(JLabel nou){
        this.add(nou);
    }
}

My original code has to add some images from an external class and I tried the same aproach but it dosen't work.How can I achive this?

我的原始代码必须添加一些来自外部类的图像,我尝试了同样的方法,但它不起作用。我怎么能得到这个?

EDIT:This is just an example I need to add this component from an external class

编辑:这只是我需要从外部类添加此组件的示例

2 个解决方案

#1

Use Container#add(Component). You can use it the same way within the constructor as you can outside of it (without the this).

使用Container#add(Component)。你可以在构造函数中以相同的方式使用它,就像在它之外一样(没有这个)。

nou.add(new JLabel("trees"));

#2

You are making the JPanel instance, but not adding to the JFrame.

您正在创建JPanel实例,但不添加到JFrame。

Also please use the convention of Capital Camel Case for class names.

另请使用Capital Camel Case的惯例作为类名。

#1