java - JPanels 在重叠期间闪烁

Question

我正在尝试制作一个在屏幕顶部随机显示 JPanel 的程序。这些 JPanel 包含笑脸的 PNG BufferedImage(通过重写 PaintComponent)。不幸的是，每当我运行程序并且面板被绘制在有任何重叠的位置时，图像就会开始闪烁(似乎是尝试同时显示自己而不是合成)。我做了一些研究并尝试解决这个问题，但没有成功。我的代码如下:

public class MainScreen extends JFrame{

public MainScreen ms;
private Smiley smileyPanel;
private int randomPosition;
public AlphaComposite ac;
private Graphics2D graphicsPane;


//main method
public static void main (String[] args){
    MainScreen ms = new MainScreen();
}

//this is my attempted fix to the program
protected void Paint (Graphics g){
    Graphics2D graphicsPane = (Graphics2D) g;
    ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER);
    graphicsPane.setComposite(ac);

    super.paint(g);
    }

//this creates the main frame and also starts creating smileys at the top
public MainScreen(){
    super("Main Screen Window");
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);

    this.setSize(500,800);
    this.getContentPane().setBackground(Color.black);
    this.setLayout(null);

    createSmiley(); createSmiley(); createSmiley(); createSmiley(); createSmiley(); createSmiley();

    this.setVisible(true);
}
//random number generator used to place an image at the top

public void setRandomPosition(){
    Random generator = new Random();
    randomPosition = generator.nextInt(473);
}

//this is the method to create an image at a random location at the top
public void createSmiley(){
    smileyPanel = new Smiley();
    this.add(smileyPanel);
    setRandomPosition();
    smileyPanel.setBounds(randomPosition, 0, 28, 29);
}
}

和我的其他类(class):

public class Smiley extends JPanel{

private BufferedImage smileyFace;
private Dimension smileyPosition;
private File smileyFile;

public Smiley() {
    //this is the code to retrieve the smiley file
    try{
    smileyFile = new File("C:\\Users\\Devon\\Desktop\\smiley.png");
    smileyFace = ImageIO.read(smileyFile);
    } 
    catch (Exception e){
        System.out.println("There was an error finding or reading the file \" smiley.png.\"");
    }
}

//override of paintComponent method in order to display the grabbed image file onto a JPanel
@Override
protected void paintComponent(Graphics g){
    super.paintComponent(g);
    g.drawImage(smileyFace, 0, 0, null);
    super.setBackground(null);
    super.setSize(28,29);
}
}

Answer 1

1. 绘画方法仅用于绘画。您不应该在绘画方法中设置组件的属性。

2. 你为什么还要进行定制绘画？您可以只使用带有图标的 JLabel。