我不明白為什么 JScrollpane 不會被添加到 JTextArea，這是因為某種布局問題嗎？
這是我朋友制作的文本編輯器，他最初只用 AWT 制作，但后來我用 Swing 的 JTextArea 替換了 AWT TextArea 來包裝文本。
輸出：
編輯：感謝所有為我投入時間的人。我發現將 JTextArea 添加到 Frame 是實際問題，因為它已經添加到 JScrollPane 中；并且 JScrollPane 已經添加到 Frame 中。所以我只是洗掉了將 JTextArea 添加到 Frame 的行，這一行寫在我在代碼中創建 Themes 的上方。
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
//---------------------------------------
class MyFrame extends JFrame { // creating class name is 'Myframe' extending from 'JFrame' class
MenuBar bar;
Menu menu1, menu2, format_menu, font_size, theme;
MenuItem new_item1, item2, item3, item4, item5, item6, item7, item8;
MenuItem dracula, queen, dawn, light;
MenuItem size_8, size_12, size_16, size_20, size_24, size_28;
JTextArea jTextArea;
String text;
MyFrame() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Untitled - CodePad");
// this is for shortcut keys
MenuShortcut menuShortcut_new_item1 = new MenuShortcut(KeyEvent.VK_N);
MenuShortcut menuShortcut_item2 = new MenuShortcut(KeyEvent.VK_O);
MenuShortcut menuShortcut_item3 = new MenuShortcut(KeyEvent.VK_S);
MenuShortcut menuShortcut_item4 = new MenuShortcut(KeyEvent.VK_X);
MenuShortcut menuShortcut_item5 = new MenuShortcut(KeyEvent.VK_C);
MenuShortcut menuShortcut_item6 = new MenuShortcut(KeyEvent.VK_V);
MenuShortcut menuShortcut_item7 = new MenuShortcut(KeyEvent.VK_T);
MenuShortcut menuShortcut_item8 = new MenuShortcut(KeyEvent.VK_A);
// -------------------------------------------
// setting icon
Image icon = Toolkit.getDefaultToolkit().getImage(".//res//icon.png");
setIconImage(icon);
//
bar = new MenuBar(); // creating object of menubar and giving it reference
menu1 = new Menu("File");// creating object of menu as 'File' and giving it reference
menu2 = new Menu("Edit");// creating object of menu as 'Edit' and giving it reference
format_menu = new Menu("Format");// creating object of menu as 'Format' and giving it reference
font_size = new Menu("Font Size");// creating object of menu as 'Font Size' and giving it reference
theme = new Menu("Theme");// creating object of menu as 'Theme' and giving it reference
//// creating object of MenuItem and giving it reference,and Passing arguments
//// 'label','menushortcut'
new_item1 = new MenuItem("New", menuShortcut_new_item1);
item2 = new MenuItem("Open", menuShortcut_item2);
item3 = new MenuItem("Save", menuShortcut_item3);
item4 = new MenuItem("Exit", menuShortcut_item4);
item5 = new MenuItem("Copy", menuShortcut_item5);
item6 = new MenuItem("Paste", menuShortcut_item6);
item7 = new MenuItem("Cut", menuShortcut_item7);
item8 = new MenuItem("Select All", menuShortcut_item8);
// ------------------done--------------
// creating menuItem for font size menu
size_8 = new MenuItem("8");
size_12 = new MenuItem("12");
size_16 = new MenuItem("16");
size_20 = new MenuItem("20");
size_24 = new MenuItem("24");
size_28 = new MenuItem("28");
// -------------------done-------------------
// creating menuItem for theme menu
dracula = new MenuItem("Dracula");
queen = new MenuItem("Queen");
dawn = new MenuItem("Dawn");
light = new MenuItem("Light");
// creating menuItem for theme menu
// adding new_item1,2,3,4 to menu1 ,that is new,open,save,exit
menu1.add(new_item1);
menu1.add(item2);
menu1.add(item3);
menu1.add(item4);
// ------------------Done-------------------
// adding item5,6,7,8 to menu2 ,that is copy,paste,cut,and select all
menu2.add(item5);
menu2.add(item6);
menu2.add(item7);
menu2.add(item8);
// -------done---------------------------------------------------------
format_menu.add(font_size);// adding font_size menu to format menu so it becomes submenu
// adding MenuItems to font_size menu
font_size.add(size_8);
font_size.add(size_12);
font_size.add(size_16);
font_size.add(size_20);
font_size.add(size_24);
font_size.add(size_28);
// ---------done------------------------
// adding MenuItem to theme Menu-------
theme.add(dracula);
theme.add(queen);
theme.add(dawn);
theme.add(light);
// ---------done------------------------
jTextArea = new JTextArea();// adding jTextArea
jTextArea.setLineWrap(true);
JScrollPane scroll = new JScrollPane(jTextArea, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
add(scroll);
// adding menus to bar
bar.add(menu1);
bar.add(menu2);
bar.add(format_menu);
bar.add(theme);
setMenuBar(bar); // settingmenubar as bar
add(jTextArea);// adding text area
// declaring some colors using rgb
Color dracula_Color = new Color(39, 40, 34);
Color green_Color = new Color(166, 226, 41);
Color orange_Color = new Color(219, 84, 34);
Color queen_Color = new Color(174, 129, 219);
// setting default foreground color of jTextArea and setting font
jTextArea.setForeground(Color.BLUE);
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 15));
// setting size and location and visibility
setSize(1000, 600);
setLocationRelativeTo(null);
setVisible(true);
item2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
FileDialog dialog = new FileDialog(new Frame(), "Open", FileDialog.LOAD); // this will load the
// fileDialog
dialog.setVisible(true);// this will make dialog visible
String path = dialog.getDirectory() dialog.getFile(); // this will select the path of selected file
// and put it into 'path'
setTitle(dialog.getFile() " - CodePad");// this will set Title to selected file name and -CodePad
try {
FileInputStream fi = new FileInputStream(path);
byte b[] = new byte[fi.available()];
fi.read(b);
String str = new String(b); // this will store b in str
jTextArea.setText(str);// this will display text in 'str' in jTextArea
fi.close();// this will close fi
} catch (Exception e) {
System.out.println("Something went Wrong :(");
}
}
});
new_item1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
setTitle("Untitled - CodePad");
jTextArea.setText(" ");
}
});
item3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
FileDialog dialog = new FileDialog(new Frame(), "Save ", FileDialog.SAVE);
dialog.setVisible(true);
String path = dialog.getDirectory() dialog.getFile();
setTitle(dialog.getFile() "- CodePad");
try {
FileWriter fw = new FileWriter(path);
fw.write(jTextArea.getText());
fw.close();
} catch (Exception e) {
System.out.println("Something went Wrong :(");
}
}
});
item4.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
// setVisible(false);//this will make frame invisible
System.exit(0);
}
});
item5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
text = jTextArea.getSelectedText();// this will store selected text in to variable 'text'
}
});
item6.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.insert(text, jTextArea.getCaretPosition()); // this will insert the text present in 'text'
// variable at the carret position
}
});
item7.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
text = jTextArea.getSelectedText(); // this will copy the selected text
jTextArea.replaceRange("", jTextArea.getSelectionStart(), jTextArea.getSelectionEnd()); // this will put
// ""
// to selected
// text
}
});
item8.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.selectAll(); // this will select all the text in jTextArea
}
});
// ------------------------------------------------------------------------
// --------------------------------------------------------------------------
size_8.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 8)); // this will change the size of text in
// jTextArea to 8
}
});
size_12.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 12));// this will change the size of text in
// jTextArea to 12
}
});
size_16.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 16));// this will change the size of text in
// jTextArea to 16
}
});
size_20.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 20));// this will change the size of text in
// jTextArea to 20
}
});
size_24.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 24));// this will change the size of text in
// jTextArea to 24
}
});
size_28.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 28));// this will change the size of text in
// jTextArea to 28
}
});
// --------------------------------------------------------------------------
dracula.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setBackground(dracula_Color);// this will backgound to dracula
jTextArea.setForeground(green_Color);// this will set foregrounf to green
}
});
queen.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setBackground(dracula_Color);
jTextArea.setForeground(queen_Color);
}
});
dawn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setBackground(Color.WHITE);
jTextArea.setForeground(orange_Color);
}
});
light.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jTextArea.setBackground(Color.WHITE);
jTextArea.setForeground(Color.BLUE);
}
});
// --------------------------------------------------------------------------
}
}
// ---------------------------------------
public class CodePad_updated {
public static void main(String[] args) {
new MyFrame();// object
}
}
uj5u.com熱心網友回復：
你是 Swing 的新手嗎？我沒有看到您設定內容窗格。我也沒有看到您在 actionListeners 中使用 @Override 命令。
就像我覺得可疑的幾件事一樣。我通常創建一個新的 JFrame 而不是擴展它。我認為擴展 JFrame 是一種不好的做法。但這并不是普遍的看法。然后，您將向框架添加一個面板并將其設定為 contentPane。然后您可以開始將所有內容添加到您的面板中，包括其他面板以幫助進行 UI 布局。文本欄位甚至顯示嗎？因為我懷疑它沒有。您還需要將 ScrollPane 添加到您的 contentPane，而不是您的 Frame。我建議洗掉帖子中與您的問題無關的代碼中的所有內容，即與手頭主題無關的所有內容。
編輯：您是否嘗試將 textArea 添加到 Scrollpane？它看起來像這樣。
JTextArea text = new JTextArea();
JScrollPane newScroll = new JScrollPane(text);
這對你有幫助嗎？
uj5u.com熱心網友回復：
總結
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class CodePad {
public static void main(String[] args) {
EventQueue.invokeLater(new CodeEditor()::create);
}
private static final class CodeEditor {
JMenuBar bar = new JMenuBar();
JMenu file = new JMenu("File");
JMenu edit = new JMenu("Edit");
JTextArea textArea = new JTextArea("Some text…", 8, 36);
public void create() {
JFrame f = new JFrame("CodePad");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
bar.add(file);
bar.add(edit);
f.setJMenuBar(bar);
textArea.setForeground(Color.BLUE);
textArea.setFont(new Font(Font.MONOSPACED, Font.BOLD, 16));
textArea.setLineWrap(true);
JScrollPane scrollArea = new JScrollPane(textArea);
f.add(scrollArea); // default BoderLayout.CENTER
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/323035.html