JButton需要更改JTextfield文本

这是功课。 开始Java类。 我仍然围绕着这些东西。

该项目是建立一个库存管理系统。

除了如何使这个按钮改变JTextField中的文本外，我已经弄明白了。 它需要从产品数组中添加信息（在本例中为DVD）。 本书讨论了管理JTextField的字体，位置和状态等不同方法，但它不包括格式化或调用文本方法。

这是我想要使用JTextArea做的事情的一个例子。 这基本上就是我想用JTextFields做的事情。

... // setup the interface JPanel panel = new JPanel(); txt = new JTextArea(15,40); txt.setEditable(false);//user shouldn't change it panel.add(txt); JButton next = new JButton("Next"); panel.add(next); getContentPane().add(panel); displayDVD(); } // view software public void displayDVD() { txt.setText("DVD Details:\n"); txt.append("Item number: " + inv.get(currentDisplay).getItem() + "\n"); txt.append("DVD name: " + inv.get(currentDisplay).getName() + "\n"); txt.append("Units in stock: " + inv.get(currentDisplay).getUnits() + "\n"); txt.append("Price: $" + String.format("%.2f",inv.get(currentDisplay).getPrice()) + "\n"); txt.append("Total value: $" + String.format("%.2f",inv.get(currentDisplay).value()) + "\n"); txt.append("Fee: $" + String.format("%.2f",inv.get(currentDisplay).fee()) + "\n\n"); txt.append("Total value: $" + String.format("%.2f",inv.value())); } 

到目前为止，这是我的实际代码

 // GUI with navigation and file manipulation buttons import javax.swing.*; // provides basic window features import java.awt.event.*; import java.awt.GridLayout; import java.awt.BorderLayout; public class AppGUI extends JFrame { private Inventory inv; private int currentDisplay = 0; private JPanel topButtonJPanel; private JButton topButtons[]; private JPanel labelJPanel; private JLabel labels[]; private JPanel fieldJPanel; private JTextField fields[]; private JPanel buttonJPanel; private JButton buttons[]; // LabelFrame constructor adds JLabels to JFrame public AppGUI() { super( "Inventory Program v.5" ); setLayout( new BorderLayout() ); // set frame layout setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// quit if the window is closed // initialize values RatedDVD d1 = new RatedDVD(1, "The Invisible Man", 0, 4999.99, "PG"); RatedDVD d2 = new RatedDVD(2, "The Matrix", 1, 13.01, "PG13"); RatedDVD d3 = new RatedDVD(3, "Se7en", 7, 11.11, "R"); RatedDVD d4 = new RatedDVD(4, "Oceans Eleven", 11, 9.02, "PG13"); RatedDVD d5 = new RatedDVD(5, "Hitch Hikers Guide to the Galaxy", 42, 10.00, "G"); // create inv and enter values inv = new Inventory(); inv.add(d1); inv.add(d2); inv.add(d3); inv.add(d4); inv.add(d5); inv.sort(); topButtons = new JButton[ 6 ]; // create topButtons array topButtonJPanel = new JPanel(); // set up panel topButtonJPanel.setLayout( new GridLayout( 1, topButtons.length, 2, 2 ) ); topButtons[0] = new JButton( "Load file" ); topButtons[1] = new JButton( "Add" ); topButtons[2] = new JButton( "Modify" ); topButtons[3] = new JButton( "Delete" ); topButtons[4] = new JButton( "Search" ); topButtons[5] = new JButton( "Save" ); for(int count=0;count<topButtons.length;count++){topButtonJPanel.add(topButtons[count]);} //add( topButtonJPanel, BorderLayout.NORTH ); // this is for next weeks assignment labels = new JLabel[8]; labelJPanel = new JPanel(); labelJPanel.setLayout( new GridLayout( labels.length, 1 )); labels[0] = new JLabel( "Item ID" ); labels[1] = new JLabel( "Name" ); labels[2] = new JLabel( "Rating" ); labels[3] = new JLabel( "# in Stock" ); labels[4] = new JLabel( "Price" ); labels[5] = new JLabel( "Restocking Fee" );//[DEBUG] ref actual Variable labels[6] = new JLabel( "Inventory Value with Fee (5%)" ); labels[7] = new JLabel( "Total Value with Fee(for all items)" ); for(int count=0;count<labels.length;count++){labelJPanel.add(labels[count]);} add( labelJPanel, BorderLayout.WEST ); fields = new JTextField[8]; fieldJPanel = new JPanel(); int spaces = 28; fieldJPanel.setLayout( new GridLayout( labels.length, 1 )); fields[0] = new JTextField( "", spaces ); fields[1] = new JTextField( "", spaces ); fields[2] = new JTextField( "", spaces ); fields[3] = new JTextField( "", spaces ); fields[4] = new JTextField( "", spaces ); fields[5] = new JTextField( "", spaces ); fields[6] = new JTextField( "", spaces ); fields[7] = new JTextField( "", spaces ); for(int count=0;count<fields.length;count++) { fields[count].setEditable( false ); fieldJPanel.add(fields[count]); } add( fieldJPanel, BorderLayout.EAST ); buttons = new JButton[ 5 ]; // create buttons array buttonJPanel = new JPanel(); // set up panel buttonJPanel.setLayout( new GridLayout( 1, buttons.length, 2, 2 ) ); buttons[0] = new JButton( "First" ); buttons[0].addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { if (currentDisplay != 0)currentDisplay = 0; //advance to the end } }); buttons[1] = new JButton( "Prev" ); buttons[1].addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { if (currentDisplay != 0)currentDisplay--; //advance to the end else currentDisplay = (inv.size()-1); } }); Icon bug1 = new ImageIcon( getClass().getResource( "bug1.gif" ) ); buttons[2] = new JButton( bug1 ); buttons[3] = new JButton( "Next" ); buttons[3].addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { if (currentDisplay < inv.size()-1)currentDisplay++; //advance to the end else currentDisplay = 0; stkover }}); buttons[4] = new JButton( "Last" ); buttons[4].addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { if (currentDisplay != inv.size()-1)currentDisplay = inv.size()-1; //advance to the end else currentDisplay = (inv.size()-1); } }); for(int count=0;count<buttons.length;count++){buttonJPanel.add(buttons[count]);} add( buttonJPanel, BorderLayout.SOUTH ); }// end method }// end class AppGUI 

任何提示提示或轻推赞赏。 请不要为我做这一切。

Answer 1

您向该按钮添加一个动作侦听器（以便它将侦听按钮动作（单击））。 然后编写该操作以更改TextField值。

 final JButton aButton = ...; final JTextField aTextField = ...; final String aNewText = "New TextField Value"; aButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { aTextField.setText(aNewText); } }); 

观察用’actionPerformed’访问的变量必须是final（字段除外）。

希望这可以帮助。

Answer 2

对于像“我的按钮更改我的测试框”这样的交叉引用，我们的想法是给按钮（控制器，点击时将激活的代码）提供对文本框的引用。 因此，当按下按钮时，它可以更改文本框。

它们有很多可能的改进，但这是基本的想法。

Answer 3

我想我不明白这个问题。

您知道如何将多个文本添加到单个组件。

 txt.append("Item number: " + inv.get(currentDisplay).getItem() + "\n"); txt.append("DVD name: " + inv.get(currentDisplay).getName() + "\n"); 

那么为什么将单个文本添加到多个组件这么难？

 itemTextField.setText( inv.get(currentDisplay).getItem() ); nameTextField.setText( inv.get(currentDisplay).getName() );