I'm trying to write a method that changes a text size inside of the JtextArea.

JTextArea editorPanel;

Font editorFont;

public void setSize( int size ) {

editorPanel.setFont( new Font( editorFont.getName(), editorFont.getStyle(), size ) );

}

I have an inner-class ActionListener on another class which look like;

class SizeListener implements ActionListener {

String size;

public void actionPerformed(ActionEvent e) {

JComboBox cb = (JComboBox) e.getSource();

size = (String) cb.getSelectedItem();

int i = Integer.parseInt( size );

displayFont = display.getEditorFont();

display.setSize( i );

}

}

I have implemented this actionlistener to my JComboBox, so that when I choose a new "size" from my ComboBox the text size of the JTextArea should be increased or decreased depending on the choice. Which method or implementation I can use to solve this problem?

解决方案

The easiest way is to derive a new Font based on the existing Font:

JComboBox cb = (JComboBox) e.getSource();

Integer itemSize = (Integer) cb.getSelectedItem();

float fontSize = itemSize.IntValue();

Font font = editorPanel.getFont();

editorPanel.setFont( font.deriveFont( fontSize ) );

Note in this case you would add Integer values to the combo box, not String values so there is no need to parse the selected item.

您可以使用逻辑字体“monospaced”.虽然它保证所有字符的字体大小相同,但在所有平台上都不一样.

import java.awt.Font;

import javax.swing.JFrame;

import javax.swing.JScrollPane;

import javax.swing.JTextArea;

import javax.swing.SwingUtilities;

public class TestTextArea {

private void initUI() {

JFrame frame = new JFrame("test");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JTextArea textArea = new JTextArea(24, 80);

textArea.setFont(new Font("monospaced", Font.PLAIN, 12));

frame.add(new JScrollPane(textArea));

frame.pack();

frame.setVisible(true);

}

public static void main(String[] args) {

SwingUtilities.invokeLater(new Runnable() {

@Override

public void run() {

new TestTextArea().initUI();

}

});

}

}

或者,您可以查找满足您需求的“免费”字体,将该字体嵌入代码中并使用java.awt.Font.createFont(int,InputStream)加载它.

展开全部

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class ArtFont extends JFrame implements ActionListener {

JComboBox fontType, fontSize;

JCheckBox boldBx;// 粗体按钮32313133353236313431303231363533e4b893e5b19e31333234333364

JCheckBox italicBx;// 斜体按钮

JButton colorBtn;// 颜色按钮；

String[] fontNames;// 字体名称;

String[] fontSizes;// 字体尺寸；

JLabel label;// 输入提示标签；

JTextField inputText;// 文字输入框；

JTextArea txtArea;// 文字显示区;

JPanel fontPanel;// 字体设置；

JPanel showPanel;// 显示效果区

Font font;

int boldStyle, italicStyle, underlineStyle;

int fontSizeStyle;

String fontNameStyle;

Color colorStyle = Color.black;// 设置字体的默认颜色为黑色;

public ArtFont() {

super("字体设置");

// 设置默认字体

boldStyle = 0;

italicStyle = 0;

underlineStyle = 0;

fontSizeStyle = 10;

fontNameStyle = "宋体";

font = new Font(fontNameStyle, boldStyle + italicStyle, fontSizeStyle);

fontPanel = new JPanel();

fontPanel.setLayout(new FlowLayout());

// 设置字体名字

GraphicsEnvironment ge = GraphicsEnvironment

.getLocalGraphicsEnvironment();

fontNames = ge.getAvailableFontFamilyNames();// 获得系统中所有字体的名字；

fontType = new JComboBox(fontNames);

fontType.setEditable(false);

fontType.setMaximumRowCount(10);

fontType.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

// 实现监听字体名字改变的事件

fontNameStyle = (String) e.getItem();// 程序段1

font = new Font(fontNameStyle, boldStyle + italicStyle,

fontSizeStyle);

txtArea.setFont(font);

}

});

// 设置字体大小

fontSizes = new String[63];

for (int i = 0; i < 63; i++) {

fontSizes[i] = Integer.toString((i + 10));

}

fontSize = new JComboBox(fontSizes);

fontSize.setEditable(false);

fontSize.setMaximumRowCount(10);

fontSize.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

// 实现监听字体大小改变的方法

// 程序段2

fontSizeStyle =Integer.parseInt(e.getItem().toString());

font = new Font(fontNameStyle, boldStyle + italicStyle,

fontSizeStyle);

txtArea.setFont(font);

}

});

// 设置粗体选择按钮；

boldBx = new JCheckBox("粗体");

boldBx.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

// 实现监听选择粗体状态改变的方法

if(e.getStateChange()==1) boldStyle=1;

else boldStyle=0;

font = new Font(fontNameStyle, boldStyle + italicStyle,

fontSizeStyle);

txtArea.setFont(font);// 程序段3

}

});

// 设置斜体选择按钮；

italicBx = new JCheckBox("斜体");

italicBx.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

// 实现监听选择斜体状态改变的方法

if(e.getStateChange()==1) italicStyle=2;

else italicStyle=0;

font = new Font(fontNameStyle, boldStyle + italicStyle,

fontSizeStyle);

txtArea.setFont(font);// 程序段4

}

});

// 设置颜色选择；

colorBtn = new JButton("颜色");

colorBtn.addActionListener(this);

// 设置字体面板；

fontPanel.add(fontType);

fontPanel.add(fontSize);

fontPanel.add(boldBx);

fontPanel.add(italicBx);

fontPanel.add(colorBtn);

// 设置输入提示标签

label = new JLabel("输入");

// 设置文本输入框；

inputText = new JTextField(30);

inputText.addActionListener(this);

// 设置文本显示区；

txtArea = new JTextArea(10, 80);// 20行80列；

txtArea.setFont(font);

// 设置文本面板;

showPanel = new JPanel();

showPanel.add(label);

showPanel.add(inputText);

showPanel.setLayout(new FlowLayout());

showPanel.add(new JScrollPane(txtArea));

// 设置容器;

Container container = getContentPane();

container.setLayout(new BorderLayout());

container.add(fontPanel, BorderLayout.NORTH);

container.add(showPanel, BorderLayout.CENTER);

setSize(500, 300);

setVisible(true);

}

public void actionPerformed(ActionEvent e) {

if (e.getSource() == colorBtn) {// 改变颜色

colorStyle = JColorChooser.showDialog(this, "选择字体颜色", colorStyle);

colorBtn.setForeground(colorStyle);

txtArea.setForeground(colorStyle);

} else if (e.getSource() == inputText) {// 将输入文字在文字显示区表示；

txtArea.setText(inputText.getText());

}

}

public static void main(String args[]) {

ArtFont artFont = new ArtFont();

artFont.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}

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