Java JPanel JFrame 获取高度和宽度

Question

我目前正在开发一个java项目，它由一个框架、主面板和3个子面板组成。在主面板的北边我有我的dataPanel，在西边我有我的buttonPanel，在中心我有我的有我的绘图面板

我的 DrawPanel 应显示 5 个圆圈的首字母，每当单击创建按钮时，它应绘制用户指定的 X 个圆圈数量。不过，我希望圆中心点在 DrawPanel 中全部可见，这意味着面板上切掉的圆的面积不超过 1/2。无论如何，我不想设置长度和宽度以使其相对于框架/面板尺寸动态。

这是我的代码

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

is there anyway to make it dynamic relative to the frame/panel size

您将 AncestorListener 添加到面板并处理 ancestorAdded 事件。当面板添加到可见 GUI 时，将生成此事件。

所以这意味着您的 create(...) 方法需要从此方法(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。