在GridLayout中，FlowLayout不显示组件？

问题描述

我正在创建一个应用程序来充当某些类型的中心，用户可以将快捷方式存储到他们喜欢的应用程序中并轻松启动它们。不过，我在使用 FlowLayout 时遇到了一些问题。当我使用 GridLayout 时，组件显示完美。当我使用 FlowLayout 时，根本不会显示任何内容。

I'm making an application to act as a hub of some sorts, where the user can store shortcuts to their favorite applications and easily launch them. I'm having some problems with FlowLayout, though. When I use GridLayout, the components display perfectly. When I use FlowLayout, nothing displays at all.

GridLayout：

GridLayout:

FlowLayout：

FlowLayout:

我所有改变的是 LayoutManager 。当我打电话给 getComponentCount 时，他们都回答9。

All I have changed is the LayoutManager. When I call getComponentCount, they both respond with 9.

我认为这个帖子很长，所以我把Code Tidy上的的片段（来自Pastebin）

I thought this post was pretty long, so I put a snippet of my code on Code Tidy (from Pastebin)

提前感谢您的帮助！

推荐答案

1） FlowLayout 非常接受来自 JComponent 的 PreferredSize ，每个 JComponents 屏幕上可以有不同的 Dimension

1) FlowLayout pretty accepting PreferredSize that came from JComponent, each of JComponents can have got different Dimension on the screen

示例（不明显的 getMinimumSize & getMinimumSize ）

example (uncomnent getMinimumSize & getMinimumSize)

import java.awt.*;
import javax.swing.*;

public class CustomComponent extends JFrame {

    private static final long serialVersionUID = 1L;

    public CustomComponent() {
        setTitle("Custom Component Test / BorderLayout");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new FlowLayout());
    }

    public void display() {
        add(new CustomComponents0(), BorderLayout.NORTH);
        add(new CustomComponents0(), BorderLayout.CENTER);
        add(new CustomComponents0(), BorderLayout.SOUTH);
        add(new CustomComponents0(), BorderLayout.EAST);
        pack();
        // enforces the minimum size of both frame and component
        setMinimumSize(getMinimumSize());
        setPreferredSize(getPreferredSize());
        setVisible(true);
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                CustomComponent main = new CustomComponent();
                main.display();
            }
        };
        javax.swing.SwingUtilities.invokeLater(r);
    }
}

class CustomComponents0 extends JLabel {

    private static final long serialVersionUID = 1L;

    /*@Override
    public Dimension getMinimumSize() {
    return new Dimension(200, 100);
    }

    @Override
    public Dimension getPreferredSize() {
    return new Dimension(300, 200);
    }*/
    @Override
    public void paintComponent(Graphics g) {
        int margin = 10;
        Dimension dim = getSize();
        super.paintComponent(g);
        g.setColor(Color.red);
        g.fillRect(margin, margin, dim.width - margin * 2, dim.height - margin * 2);
    }
}

2） GridLayou t为每个 JComponents 创建比例区域，然后仅接受 JComponent ，其中<$ c c更大$ c> Dimnesion 来自 PreferredSize

2) GridLayout create proportional area for every JComponents, then accepting only JComponent that have got larger Dimnesion came from PreferredSize

3） GridLayout 我说的是方法 pack（），而不是 JFrame＃setSize（），对于 FLowLayout 无关紧要，

3) for GridLayout I'm talking about method pack(), not if is there JFrame#setSize(), for FLowLayout doesn't matter,

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