Java JPanel JFrame获取高度和宽度

Question

我目前正在做一个java项目，它由一个框架、主面板和3个子面板组成。在主面板的北面我有我的dataPanel，在西面我有我的buttonPanel和在中心我有我的drawPanel

我的DrawPanel应该显示5个圆圈的初始值，每当创建按钮被点击时，它应该绘制用户指定的X个圆圈。然而，我希望圆圈中心点在DrawPanel中都是可见的，这意味着不超过任何圆圈的1/2被切断了面板。我不希望设置长度和宽度，无论如何，使其动态相对于框架/面板的大小。

我的代码

public class MainPanel extends JPanel{
private DataPanel data;
private JPanel buttonPanel;
private DrawPanel dPanel;
private JButton create;
private JButton sort;
private JButton coCenter;
private JButton reset;
public MainPanel()
{
    setLayout(new BorderLayout());
    data = new DataPanel();
    add(data, BorderLayout.NORTH);
    buttonPanelInitialize();
    add(buttonPanel,BorderLayout.WEST);
    int a,b,c;
    a = data.getDataField();
    b = data.getDataField1();
    c = data.getDataField2();
    dPanel = new DrawPanel(a,b,c);
    add(dPanel, BorderLayout.CENTER);
}
private void buttonPanelInitialize()
{
    buttonPanel = new JPanel();
    buttonPanel.setLayout(new GridLayout(4,1));
    buttonCreate();
    buttonSort();
    buttonCoCenter();
    buttonReset();
    buttonPanel.add(create);
    buttonPanel.add(sort);
    buttonPanel.add(coCenter);
    buttonPanel.add(reset);
}
private void buttonCreate()
{
    create = new JButton("Create");
    class cListener implements ActionListener
    {
        @Override
        public void actionPerformed(ActionEvent event) {
            //int amount = 0; 
            int amount = data.getDataField();
            int smallestR = data.getDataField1();
            int largestR = data.getDataField2();
            dPanel.create(amount,smallestR,largestR);
        }
    }
    ActionListener createListener = new cListener();    
    create.addActionListener(createListener);
}

和

public class DrawPanel extends JPanel{
private ArrayList<ColorCircle> circles;
private int numberOfCircles;
private int smallestRadiusSize;
private int biggestRadiusSize;
private int width;
private int height;
public DrawPanel()
{
    circles = new ArrayList<ColorCircle>();
}
public DrawPanel(int number, int smallestRadius, int biggestRadius)
{
    circles = new ArrayList<ColorCircle>();
    create(number,smallestRadius,biggestRadius);
    width = (int)Math.random()*getWidth();
    height = (int)Math.random()*getHeight();
}
public void create(int number, int smallestRadius, int biggestRadius)
{
    numberOfCircles = number;
    smallestRadiusSize = smallestRadius;
    biggestRadiusSize = biggestRadius;
    for(int i = 0; i < numberOfCircles ; i++)
    {
        int radius = (int) ((int)smallestRadiusSize+Math.random()*((int)biggestRadiusSize-(int)smallestRadiusSize+1));
        width = (int) ((int)100+Math.random()*701);    //the problem is here
        height = (int) ((int)100+Math.random()*501);   //and here this part should be dynamic
        circles.add(new ColorCircle(width,height,radius));  
        System.out.println(smallestRadiusSize);
        System.out.println(biggestRadiusSize);
        System.out.println(radius+"-----");
        System.out.println(circles.size());
        System.out.println(width+" THis is x");
        System.out.println(height+" THIs is Y");
        repaint();
    }   
}
public void paintComponent(Graphics g)
{
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;
    for(ColorCircle c : circles)
    {
        c.fill(g2);
    }
}

Answer 1

是否可以使它相对于框架/面板的大小是动态的

添加AncestorListener到面板，处理ancestorAdded事件。此事件将在面板添加到可见GUI时生成。

所以这意味着你的create(...)方法需要从这个方法(而不是构造函数)调用。然后，当代码执行时，您可以使用面板的getWidth()和getHeight()方法来获取面板的实际大小并进行处理。