actionlistener（this）无效

Question

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

class Casestudy extends JFrame implements ActionListener
{//making a facebook like program
    JButton Login,Register;
    JLabel lbl1, lbl2;
    JTextField txtEmail;
    JPasswordField txtPassword;

    public Casestudy() 
    { //setting labels button etc
        super ("Casestudy2.0");
        setLayout(new FlowLayout());
        lbl1 = new JLabel (" Username ");
        lbl2 = new JLabel (" Password ");
        txtEmail = new JTextField(10);
        Login = new JButton("Login");
        Register= new JButton("Register");
        //this

        Login.addActionListener(this);//adding listener this

        Register.addActionListener(this);
        Register.setBounds(2,250,100,20);

    }

    public void actionPerformed(ActionEvent e){

        //my code supposedly im working but im just checkin the frame and it apppars to not work properly just a frame no buttons
    }

    public static void main (String  args []){
        Casestudy use= new Casestudy();//frame size
        use.setSize(250,280);
        use.setVisible(true);
        use.setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
} 

据说我想在运行之前运行这个程序并检查框架，但它没有显示任何按钮或者无论如何请帮助我捏捏:( 换句话说，在我开始实际程序之前，我希望我的框架首先有按钮。

Answer 1

您忘了将按钮添加到JFrame：

def removeall(list,value):
    list = [n for n in list if n != value]  
    print(list)
prices = []

while True:
    usrinput = input('Please enter price or stop to stop: ')
    if usrinput == 'stop':
        break

    prices.append(float(usrinput))


print(prices)

highestprice = max(prices)
lowestprice = min(prices)

removeall(prices, highestprice)
removeall(prices, lowestprice)

print(prices)

print(sum(prices)/len(prices))