Question

我只是想知道为什么当我使用Frame Application并混合对话框和动画时，文本框被完全删除。

这是我的代码：

/* The "SpaceTravels" class.
   Date: March 2015
   Author Barrington Reid
   Description: This program asks user for identification,
   then will display a spaceship travelling through the night sky using Graphics.
   The spaceship is controlled by a slow setting, a medium setting and a fast setting.
*/
import javax.swing.*;           //Allows JOptionPane to work
import java.awt.*;

public class SpaceTravels extends JFrame
{
    ImageIcon backGnd, rckt;

    int x = 0;                //Setting the x variable as 0
    int y = 600;              //Setting the y variable as 600
    int xSpeed = 10;          //Setting the xSpeed as 10
    int ySpeed = 10;          //Setting the ySpeed as 10
    int number = 0;           //stores the verification number


    public SpaceTravels ()
    {
        super ("SpaceTravels");  // Set the frame's name
        setSize (1360, 730);     // Set the frame's size
        backGnd = new ImageIcon ("night.gif");    //Night background
        rckt = new ImageIcon ("orangerocket.png");       //Rocket
        setDefaultCloseOperation (EXIT_ON_CLOSE);       //Close the program by clicking exit
        setVisible (true);       // Show the frame
    } // Constructor


    public void paint (Graphics g)
    {
        for (int i = 0 ; i < 1000000 ; i = i + 1)
        {
            backGnd.paintIcon (this, g, 0, 0);
            rckt.paintIcon (this, g, x, y);

            y = y + ySpeed;

            for (int j = 0 ; j < 1000000 ; j = j + 1)
            {
                double k = 1;
                Math.pow (k, 2);
            }
            if ((y > 600) || (y < 50))
            {
                ySpeed = ySpeed * -1;
            }


            for (int k = 0 ; k < 1000000 ; k = k + 1)
            {
                double l = 1;
                Math.pow (l, 2);
            }
            if ((x > 600 || (x < 50))
            {
                xSpeed = xSpeed * -1;
            }
        }
    } // paint method


    public static void main (String[] args)
    {
        new SpaceTravels ();    // Create a SpaceTravels frame
        String name;            //Stores names
        int tries = 0;          //Stores the amount of tries
        String verCode = "1234567";                         //Verification Code is 1234567
        String code = "1234567";                            //Verification Code is 1234567

        JOptionPane.showMessageDialog (null, "Hello, and welcome to the Canadian Space Agency's Spacecraft Control and Simulation Program!"); //Welcome
        JOptionPane.showMessageDialog (null, "Your verification code is 1234567.");             //This is the verification code

        name = JOptionPane.showInputDialog (null, "For safety purposes, please enter your name");           //Asking for user name
        verCode = JOptionPane.showInputDialog (null, "Now, " + name + ", please enter your verification code."); //Enter the verification code: 1234567

        while ((verCode.equalsIgnoreCase ("1234567") != true) && (tries < 3))                      //3 tries to get this correct
        {
            verCode = JOptionPane.showInputDialog (null, "You have entered the wrong verification code, please try again.");
            tries = tries + 1;          //Tries goes up once each time this loop occurs.
        }

        if (code.equals (verCode))
        {
            String[] options = new String[]  //This is a code that I found on (http://stackoverflow.com/questions/1257420/making-a-joptionpane-with-4-options)
            {
                "Slow", "Medium", "Fast"     //Speed options, slow, medium and fast
            }
            ;
            int response = JOptionPane.showOptionDialog (null, "What would you like the velocity of the rocket to be?", "Rocket speed",
                    JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE,
                    null, options, options [0]);  //This is the name of the box, and what the box displays inside.
        }

        else
        {
            JOptionPane.showMessageDialog (null, "Sorry, " + name + ", you have unsuccessfully identified your session. Please try again in 10 minutes.");
        }

    }


    // main method
} // SpaceTravels class

当我删除图形代码时，消息框的工作方式应该是正确的。

Answer 1

首先覆盖paint而不调用super.paint会破坏父类提供的功能，并且不会导致绘画工作方式出现问题。不是从JFrame延伸并覆盖它的绘图例程（它足够复杂），而是从JPanel开始并覆盖它的paintComponent方法（调用{{ 1}}在你做任何自定义绘画之前）。有关详细信息，请参阅Painting in AWT and Swing和Performing Custom Painting。
确保从事件调度线程的上下文中运行UI。有关详细信息，请参阅Initial Threads

例如......

super.paintComponent

为什么我的动画剪切了我的消息框？

1 个答案: