JButton不會出現，直到被淹沒

Question

當我運行我的程序時，一切都按照計劃進行，除非按鈕我必須更改屏幕上的卡片纔會出現，直到它被淹沒。我假設這是因爲無論容納圖像的容器都結束了它，但我不知道如何將它移動到背景中，甚至可以使用什麼樣的容器來添加圖像。

import java.io.*; 
import java.awt.*; 
import javax.swing.*; 
import java.util.Random; 
import java.awt.event.*; 
import javax.imageio.ImageIO; 
import java.awt.image.BufferedImage; 

public class oneplayer extends JFrame { 
    BufferedImage image1, image2, image3, image4; 
    Random gen = new Random(); 
    public void redo() { 
     int p1, p2, p3, p4; 
     p1 = gen.nextInt(13) + 1; 
     p2 = gen.nextInt(13) + 14; 
     p3 = gen.nextInt(13) + 27; 
     p4 = gen.nextInt(13) + 40; 
     try { 
     File input1 = new File("C:/Users/Mike/Desktop/eclipse/workspace/inClass/src/" + p1 + ".png"); 
     File input2 = new File("C:/Users/Mike/Desktop/eclipse/workspace/inClass/src/" + p2 + ".png"); 
     File input3 = new File("C:/Users/Mike/Desktop/eclipse/workspace/inClass/src/" + p3 + ".png"); 
     File input4 = new File("C:/Users/Mike/Desktop/eclipse/workspace/inClass/src/" + p4 + ".png"); 
     image1 = ImageIO.read(input1); 
     image2 = ImageIO.read(input2); 
     image3 = ImageIO.read(input3); 
     image4 = ImageIO.read(input4); 
    } catch (IOException ie) { 
     System.out.println("Error:"+ie.getMessage()); 
    } 
    repaint(); 
} 

public oneplayer() { 
    JPanel buttonPanel = new JPanel(); 
    setLayout(new BorderLayout()); 
    JButton refresh = new JButton("Refresh"); 
    refresh.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) { 
      redo(); 
     } 
    }); 
    add(buttonPanel, BorderLayout.SOUTH); 
    buttonPanel.add(refresh, BorderLayout.CENTER); 
    redo(); 
} 

public void paint(Graphics g) { 
    g.drawImage(image1, 20, 55, null); 
    g.drawImage(image2, 96, 55, null); 
    g.drawImage(image3, 172, 55, null); 
    g.drawImage(image4, 248, 55, null); 
} 

public static void main(String args[]) { 
    oneplayer frame = new oneplayer(); 
    frame.setTitle("Random Cards"); 
    frame.setSize(350, 200); 
    frame.setLocationRelativeTo(null); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    frame.setVisible(true); 
} 
} 

Answer 1

你需要打電話給你的super.paint(g)功能paint(Graphics)內，以確保框架中的Swing組件正常顯示。

Answer 2

尚未對您的示例進行測試，但我認爲您需要在重寫Frame上的繪畫時調用父類的繪畫，以便Frame的組件顯示出來。像這樣：

public void paint(Graphics g) { 
    super.paint(g); 
    g.drawImage(image1, 20, 55, null); 
    g.drawImage(image2, 96, 55, null); 
    g.drawImage(image3, 172, 55, null); 
    g.drawImage(image4, 248, 55, null); 
} 

Answer 3

請勿重寫paint()方法。而是覆蓋主容器的paintComponent()。

呼叫super.paintComponent(g)

不要延長JFrame，但如JPanel，將所有內容添加到面板並將該面板設置爲通常的JFrame實例的內容窗格。