自动调整GridBagLayout中组件的大小 [英] Automatically re-sizing a component within a GridBagLayout

问题描述

在这段代码中，我在GridBagLayout中有一个面板，其中包含一个JLabel和JTextField.

In this code I have a panel in the GridBagLayout which contains a JLabel and a JTextField.

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

public class Simple
{
    JFrame simpleWindow = new JFrame("Simple MCVE");

    JPanel  simplePanel = new JPanel();

    JLabel lblSimple;
    JTextField txtSimple;

    public void numberConvertGUI()
    {
        simpleWindow.setBounds(10, 10, 420, 80);

        simpleWindow.setMinimumSize(new Dimension(420, 80));

        simpleWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        simpleWindow.setLayout(new GridLayout(1,1));

        createSimplePanel();

        simpleWindow.getContentPane().add(simplePanel);

        simpleWindow.setVisible(true);
    }

    public void createSimplePanel()
    {
        simplePanel.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();

        lblSimple = new JLabel();
        c.weightx = 0.0;
        c.weighty = 1.0;
        c.fill = GridBagConstraints.BOTH;
        c.insets = new Insets(0,2,0,2);
        c.gridx = 0;
        c.gridy = 0;
        c.ipady = 0;
        lblSimple.setText("Next to me is a JTextField: ");
        lblSimple.setHorizontalAlignment(JLabel.RIGHT);
        simplePanel.add(lblSimple, c);

        txtSimple = new JTextField();
        c.weightx = 0.5;
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 5;
        c.gridx = 1;
        c.gridy = 0;
        c.insets = new Insets(0,2,0,2);
        simplePanel.add(txtSimple, c);
    }

    public static void main(String[] args)
    {
        Simple s = new Simple();
        s.numberConvertGUI();
    }
}

我希望能够根据输入的数据量自动调整文本字段的大小.例如，当字符串到达边缘时如何自动调整该组件的大小?"时，在JTextField中输入，看起来像这样.

I would like to be able to automatically re-size the text field dependent on the amount of data entered in it. For example when the string "How do I re-size this component automatically when the edge of it is reached?" is entered in the JTextField it looks like this.

但是，当我输入字符串时，我希望JTextBox和JFrame自动调整大小以产生看起来像这样的东西.

However as I enter the string I would like the JTextBox and the JFrame to automatically re-size to produce something which looks a bit like this.

唯一的问题是我不知道有什么可以做的.对于完成此任务的任何帮助，我将不胜感激.

The only problem is I am not aware of anything which allows me to do this. I would greatly appreciate any help with accomplishing this task.

修改

当组件自动调整大小时，我也希望该组件的最大大小.这样，随着输入更多数据，该组件将无法继续调整某人计算机显示器的大小

When the component is re-sized automatically I would also like there to be a maximum size for that component. This way as more data is entered the component will not keep re-sizing off of someone's computer monitor

推荐答案

Swing中没有内置功能可以做到这一点.

There is no built in functionality to do this provided within Swing.

您需要做的是在文本字段后面的文档中添加DocumentListener，并在添加或删除文本时收到通知.

What you will need to do is add a DocumentListener to the document behind the text field and be notified whenever text is added or removed from it.

然后，您将需要为文本字段计算所需的新大小(这可能很棘手-您可能需要使用FontMetrics)并调整控件的大小以匹配.此时，只需查看要调整大小的尺寸与您希望允许的最大尺寸相比，即可轻松实现最大尺寸.

You will then need to calculate the new size you want for your text field (which can be tricky in of itself - you will probably need to use FontMetrics) and re-size the control to match. The maximum size you can implement easily at this point just by looking at the size you are re-sizing to compared to the maximum you wish to allow.

有关DocumentListener的信息，请参见此处: https://docs.oracle.com/javase/tutorial/uiswing/events /documentlistener.html

See here for info on DocumentListener: https://docs.oracle.com/javase/tutorial/uiswing/events/documentlistener.html

有关FontMetrics的信息，请参见此处: https://docs.oracle.com/javase/tutorial/2d/text /measuringtext.html

See here for info on FontMetrics: https://docs.oracle.com/javase/tutorial/2d/text/measuringtext.html

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