Textfield to string java
JTextField is a lightweight component that allows the editing of a single line of text. For information on and examples of using text fields, see How to Use Text Fields in The Java Tutorial. JTextField is intended to be source-compatible with java.awt.TextField where it is reasonable to do so. This component has capabilities not found in the java.awt.TextField class. The superclass should be consulted for additional capabilities. JTextField has a method to establish the string used as the command string for the action event that gets fired. The java.awt.TextField used the text of the field as the command string for the ActionEvent . JTextField will use the command string set with the setActionCommand method if not null , otherwise it will use the text of the field as a compatibility with java.awt.TextField . The method setEchoChar and getEchoChar are not provided directly to avoid a new implementation of a pluggable look-and-feel inadvertently exposing password characters. To provide password-like services a separate class JPasswordField extends JTextField to provide this service with an independently pluggable look-and-feel. The java.awt.TextField could be monitored for changes by adding a TextListener for TextEvent ‘s. In the JTextComponent based components, changes are broadcasted from the model via a DocumentEvent to DocumentListeners . The DocumentEvent gives the location of the change and the kind of change if desired. The code fragment might look something like:
DocumentListener myListener = ??; JTextField myArea = ??; myArea.getDocument().addDocumentListener(myListener); The horizontal alignment of JTextField can be set to be left justified, leading justified, centered, right justified or trailing justified. Right/trailing justification is useful if the required size of the field text is smaller than the size allocated to it. This is determined by the setHorizontalAlignment and getHorizontalAlignment methods. The default is to be leading justified. How the text field consumes VK_ENTER events depends on whether the text field has any action listeners. If so, then VK_ENTER results in the listeners getting an ActionEvent, and the VK_ENTER event is consumed. This is compatible with how AWT text fields handle VK_ENTER events. If the text field has no action listeners, then as of v 1.3 the VK_ENTER event is not consumed. Instead, the bindings of ancestor components are processed, which enables the default button feature of JFC/Swing to work. Customized fields can easily be created by extending the model and changing the default model provided. For example, the following piece of code will create a field that holds only upper case characters. It will work even if text is pasted into from the clipboard or it is altered via programmatic changes.
public class UpperCaseField extends JTextField < public UpperCaseField(int cols) < super(cols); >protected Document createDefaultModel() < return new UpperCaseDocument(); >static class UpperCaseDocument extends PlainDocument < public void insertString(int offs, String str, AttributeSet a) throws BadLocationException < if (str == null) < return; >char[] upper = str.toCharArray(); for (int i = 0; i < upper.length; i++) < upper[i] = Character.toUpperCase(upper[i]); >super.insertString(offs, new String(upper), a); > > > Warning: Swing is not thread safe. For more information see Swing’s Threading Policy. Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder .
Как получить значение из JTextField в Java Swing?
Как получить значение из текстового поля и actionPerformed() ? Мне нужно значение, которое нужно преобразовать в String для дальнейшей обработки. Я создал текстовое поле при нажатии кнопки Мне нужно сохранить значение, введенное в String , можете ли вы предоставить фрагмент кода?
Это дубликат. Может быть, не одного вопроса. Но это не новая проблема. Получение текста и добавление действия слушателя . Кроме того, я уверен, что если вы поищете в Google, есть даже пример того, что вы описываете.
Его очень легко получить значение из JTextfield .. попробуйте прочитать Java документ . это поможет вам разрабатывать программы ..
6 ответов
button.addActionListener(new ActionListener() < public void actionPerformed(ActionEvent ae)< String textFieldValue = testField.getText(); // . do some operation on value . >>) * First we declare JTextField like this JTextField testField = new JTextField(10); * We can get textfield value in String like this on any button click event. button.addActionListener(new ActionListener() < public void actionPerformed(ActionEvent ae)< String getValue = testField.getText() >>) Как получить значение из текстового поля?
mytextField.addActionListener(this); public void actionPerformed(ActionEvent evt)
Так что может быть что-то вроде String newline = System.getProperty(«line.separator»); было бы правильно?
import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Swingtest extends JFrame implements ActionListener < JTextField txtdata; JButton calbtn = new JButton("Calculate"); public Swingtest() < JPanel myPanel = new JPanel(); add(myPanel); myPanel.setLayout(new GridLayout(3, 2)); myPanel.add(calbtn); calbtn.addActionListener(this); txtdata = new JTextField(); myPanel.add(txtdata); >public void actionPerformed(ActionEvent e) < if (e.getSource() == calbtn) < String data = txtdata.getText(); //perform your operation System.out.println(data); >> public static void main(String args[]) < Swingtest g = new Swingtest(); g.setLocation(10, 10); g.setSize(300, 300); g.setVisible(true); >> Пожалуйста, не кричи; это заставляет вас звучать сердито. Даже игнорируя отсутствующий импорт, похоже, что вам не хватает конструктора. Могу ли я помочь вам исправить это?
Нет, это хуже; Я пытаюсь помочь улучшить этот ответ. Похоже, вы объявляете class serverfact и class serverfact что-то с именем VIEWBTN . Ни одно из имен не использует стиль, с которым я знаком.
ха-ха . это круто, командовать upvote 😉 Кстати: вы должны придерживаться соглашений об именовании Java
@kleopatra прав насчет соглашений об именах: они улучшают читабельность, например, class ServerFact или JTextField resText . Ранее я проголосовал против этого ответа, потому что он вводил в заблуждение; теперь это правильно, поэтому я поменял голосование. Я не уверен, что это что-то добавляет к предыдущим ответам, но я полагаюсь на @harshini, полезно ли это. Я был бы рад изучить другие ответы, которые вы предложили. Я не могу обещать голосование с повышением, но я могу обещать честный, конструктивный обзор.
Class JTextField
JTextField is intended to be source-compatible with java.awt.TextField where it is reasonable to do so. This component has capabilities not found in the java.awt.TextField class. The superclass should be consulted for additional capabilities.
JTextField has a method to establish the string used as the command string for the action event that gets fired. The java.awt.TextField used the text of the field as the command string for the ActionEvent . JTextField will use the command string set with the setActionCommand method if not null , otherwise it will use the text of the field as a compatibility with java.awt.TextField .
The method setEchoChar and getEchoChar are not provided directly to avoid a new implementation of a pluggable look-and-feel inadvertently exposing password characters. To provide password-like services a separate class JPasswordField extends JTextField to provide this service with an independently pluggable look-and-feel.
The java.awt.TextField could be monitored for changes by adding a TextListener for TextEvent ‘s. In the JTextComponent based components, changes are broadcasted from the model via a DocumentEvent to DocumentListeners . The DocumentEvent gives the location of the change and the kind of change if desired. The code fragment might look something like:
DocumentListener myListener = ??; JTextField myArea = ??; myArea.getDocument().addDocumentListener(myListener); The horizontal alignment of JTextField can be set to be left justified, leading justified, centered, right justified or trailing justified. Right/trailing justification is useful if the required size of the field text is smaller than the size allocated to it. This is determined by the setHorizontalAlignment and getHorizontalAlignment methods. The default is to be leading justified.
How the text field consumes VK_ENTER events depends on whether the text field has any action listeners. If so, then VK_ENTER results in the listeners getting an ActionEvent, and the VK_ENTER event is consumed. This is compatible with how AWT text fields handle VK_ENTER events. If the text field has no action listeners, then as of v 1.3 the VK_ENTER event is not consumed. Instead, the bindings of ancestor components are processed, which enables the default button feature of JFC/Swing to work.
Customized fields can easily be created by extending the model and changing the default model provided. For example, the following piece of code will create a field that holds only upper case characters. It will work even if text is pasted into from the clipboard or it is altered via programmatic changes.
public class UpperCaseField extends JTextField < public UpperCaseField(int cols) < super(cols); >protected Document createDefaultModel() < return new UpperCaseDocument(); >static class UpperCaseDocument extends PlainDocument < public void insertString(int offs, String str, AttributeSet a) throws BadLocationException < if (str == null) < return; >char[] upper = str.toCharArray(); for (int i = 0; i < upper.length; i++) < upper[i] = Character.toUpperCase(upper[i]); >super.insertString(offs, new String(upper), a); > > > Warning: Swing is not thread safe. For more information see Swing’s Threading Policy.
Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans has been added to the java.beans package. Please see XMLEncoder .
Class JTextField
JTextField is intended to be source-compatible with java.awt.TextField where it is reasonable to do so. This component has capabilities not found in the java.awt.TextField class. The superclass should be consulted for additional capabilities.
JTextField has a method to establish the string used as the command string for the action event that gets fired. The java.awt.TextField used the text of the field as the command string for the ActionEvent . JTextField will use the command string set with the setActionCommand method if not null , otherwise it will use the text of the field as a compatibility with java.awt.TextField .
The method setEchoChar and getEchoChar are not provided directly to avoid a new implementation of a pluggable look-and-feel inadvertently exposing password characters. To provide password-like services a separate class JPasswordField extends JTextField to provide this service with an independently pluggable look-and-feel.
The java.awt.TextField could be monitored for changes by adding a TextListener for TextEvent ‘s. In the JTextComponent based components, changes are broadcasted from the model via a DocumentEvent to DocumentListeners . The DocumentEvent gives the location of the change and the kind of change if desired. The code fragment might look something like:
DocumentListener myListener = ??; JTextField myArea = ??; myArea.getDocument().addDocumentListener(myListener); The horizontal alignment of JTextField can be set to be left justified, leading justified, centered, right justified or trailing justified. Right/trailing justification is useful if the required size of the field text is smaller than the size allocated to it. This is determined by the setHorizontalAlignment and getHorizontalAlignment methods. The default is to be leading justified.
How the text field consumes VK_ENTER events depends on whether the text field has any action listeners. If so, then VK_ENTER results in the listeners getting an ActionEvent, and the VK_ENTER event is consumed. This is compatible with how AWT text fields handle VK_ENTER events. If the text field has no action listeners, then as of v 1.3 the VK_ENTER event is not consumed. Instead, the bindings of ancestor components are processed, which enables the default button feature of JFC/Swing to work.
Customized fields can easily be created by extending the model and changing the default model provided. For example, the following piece of code will create a field that holds only upper case characters. It will work even if text is pasted into from the clipboard or it is altered via programmatic changes.
public class UpperCaseField extends JTextField < public UpperCaseField(int cols) < super(cols); >protected Document createDefaultModel() < return new UpperCaseDocument(); >static class UpperCaseDocument extends PlainDocument < public void insertString(int offs, String str, AttributeSet a) throws BadLocationException < if (str == null) < return; >char[] upper = str.toCharArray(); for (int i = 0; i < upper.length; i++) < upper[i] = Character.toUpperCase(upper[i]); >super.insertString(offs, new String(upper), a); > > > Warning: Swing is not thread safe. For more information see Swing’s Threading Policy.
Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans has been added to the java.beans package. Please see XMLEncoder .