英文:
Weird BoxLayout painting
问题
我尝试按行显示一个对象，其中每一行都是一个对象。然后我使用了一个框布局，但这样做时只有顶部图层（也就是最后一个被调用的对象）被绘制，如何修复这个问题？
这是一个最小的示例：
import javax.swing.*;import java.awt.*;public class Main {public static void main(String[] args) {MainFrame frame = new MainFrame();}}private class MainFrame extends JFrame {public MainFrame(){setSize(600,400);setLocationRelativeTo(null);setVisible(true);setContentPane(new Container());}}private class Container extends JPanel {public Container(){setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));for(int i =0;i<10;i++){add(new Line());}}}private class Line extends JPanel {@Overrideprotected void paintComponent(Graphics g) {super.paintComponent(g);g.setColor(Color.green);g.fillRect(getX(),getY(),getWidth(),getHeight());}}
这是我得到的效果：
这是我期望的效果：
一些测试（在JBackPannel类的paint方法中的蓝色矩形）向我展示了某处正在绘制一个白色画布，但我不知道是在哪里以及为什么...
这是一个最小示例的链接。
英文:
I was trying to dysplay an object line by line where each line is an object. Then I use a box Layout but when I do so only the top layer (which is the last object called) is drawed how can I fiw this ?
here is a minimal exemple :
import javax.swing.*;import java.awt.*;public class Main {public static void main(String[] args) {MainFrame frame = new MainFrame();}}private class MainFrame extends JFrame {public MainFrame(){setSize(600,400);setLocationRelativeTo(null);setVisible(true);setContentPane(new Container());}}private class Container extends JPanel {public Container(){setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));for(int i =0;i<10;i++){add(new Line());}}}private class Line extends JPanel {@Overrideprotected void paintComponent(Graphics g) {super.paintComponent(g);g.setColor(Color.green);g.fillRect(getX(),getY(),getWidth(),getHeight());}}
here is what I've got :
and what I've expected :
Some test (the blue rectangle in the paint method of the JBackPannel class) showed me that somewhere something is drawing a white canvas, but I don't know where and why ...
here is a link to a minimal exemple
答案1
得分: 2
自定义绘制始终相对于组件而不是父面板中组件的位置进行。所以：
g.fillRect(getX(),getY(),getWidth(),getHeight());
应该是：
g.fillRect(0, 0, getWidth(), getHeight());
英文:
Custom painting is always done relative to the component, not the components location in the parent panel.
So:
g.fillRect(getX(),getY(),getWidth(),getHeight());
should be:
g.fillRect(0, 0, getWidth(), getHeight());
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