Java 循环通过JPanel中的嵌套字段
我已经创建了两个类，第一个是生成JTextFields，第二个是将这些JTextFields注入JPanel。我正在尝试将.setText设置到每个JTextField，但很简单Java 循环通过JPanel中的嵌套字段,java,swing,loops,constructor,Java,Swing,Loops,Constructor,我已经创建了两个类，第一个是生成JTextFields，第二个是将这些JTextFields注入JPanel。我正在尝试将.setText设置到每个JTextField，但很简单 for (Field f: fields) { f.setValue("my text"); } 不起作用-它只将文本设置为一个JPanel中的JTextFields。由于每个JTextField都有uniqe fieldID，您能告诉我如何将其设置为SETXT（setValue）吗？这些值需
for (Field f: fields) {
f.setValue("my text");
}
public class Field {
JTextField field = new JTextField();
static int fieldID = 0;
private String text;
public Field() {
fieldID++;
}
public String getValue() {
return field.getText();
}
public void setValue(String text) {
field.setText(text);
}
}
public class Frame extends JFrame {
public Frame() {
Field[] fields = new Field[9];
JPanel[] corePane = new JPanel[9];
JPanel frontPane = new JPanel();
frontPane.setLayout(new GridLayout(3, 3));
for (int i = 0; i < corePane.length; i++) {
corePane[i] = new JPanel();
for (int j = 0; j < 9; j++) {
fields[j] = new Field();
corePane[i].add(fields[j].field);
}
corePane[i].setLayout(new GridLayout(3, 3));
frontPane.add(corePane[i]);
}
setLayout(new BorderLayout());
setSize(300, 300);
getContentPane().add(frontPane, BorderLayout.CENTER);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String args[]) {
SwingUtilities.invokeLater(Frame::new);
}
}
公共类字段{
JTextField=新的JTextField（）；
静态int fieldID=0；
私有字符串文本；
公共领域（）{
fieldID++；
}
公共字符串getValue（）{
返回字段。getText（）；
}
公共void设置值（字符串文本）{
field.setText（文本）；
}
}
公共类框架扩展了JFrame{
公共框架（）{
字段[]字段=新字段[9]；
JPanel[]corePane=新的JPanel[9]；
JPanel frontPane=新的JPanel（）；
设置布局（新的网格布局（3,3））；
对于（int i=0；i字段可能需要是一个二维数组，例如
Field[][] fields = new Field[9][9];
这样，您就可以访问给定面板（第一维）的字段（第二维），即fields[pane][field]
显然，在for循环中，需要正确初始化字段数组，例如，字段[i]=新字段[9]
这可能会使您的代码看起来更像
public class Field {
JTextField field = new JTextField();
static int fieldID = 0;
private String text;
public Field() {
fieldID++;
}
public String getValue() {
return field.getText();
}
public void setValue(String text) {
field.setText(text);
}
}
public class Frame extends JFrame {
public Frame() {
Field[][] fields = new Field[9][9];
JPanel[] corePane = new JPanel[9];
JPanel frontPane = new JPanel();
frontPane.setLayout(new GridLayout(3, 3));
for (int i = 0; i < corePane.length; i++) {
corePane[i] = new JPanel();
fields[i] = new Field[9];
for (int j = 0; j < 9; j++) {
fields[i][j] = new Field();
corePane[i].add(fields[i][j].field);
}
corePane[i].setLayout(new GridLayout(3, 3));
frontPane.add(corePane[i]);
}
setLayout(new BorderLayout());
setSize(300, 300);
getContentPane().add(frontPane, BorderLayout.CENTER);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String args[]) {
SwingUtilities.invokeLater(Frame::new);
}
}
将意味着字段
的每个实例都将具有相同的字段ID
，无论您将其更改为什么。对我来说（根据你所说的），以这种方式使用static
是没有意义的
还有一些替代方案，它们可能提供更好、更可重用的解决方案作为@MadProgrammer解决方案的替代方案，我可以为您提供一些有用的方法，可以帮助您解决这些任务，而无需声明任何数组
/**
* Searches for all children of the given component which are instances of the given class.
*
* @param aRoot start object for search. May not be null.
* @param aClass class to search. May not be null.
* @param <E> class of component.
* @return list of all children of the given component which are instances of the given class. Never null.
*/
public static <E> List<E> getAllChildrenOfClass(Container aRoot, Class<E> aClass) {
return getAllChildrenOfClass(aRoot, aClass, e -> true);
}
/**
* Searches for all children of the given component which are instances of the given class and satisfies the given condition.
*
* @param aRoot start object for search. May not be null.
* @param aClass class to search. May not be null.
* @param condition condition to be satisfied. May not be null.
* @param <E> class of component.
* @return list of all children of the given component which are instances of the given class. Never null.
*/
public static <E> List<E> getAllChildrenOfClass(Container aRoot, Class<E> aClass, Predicate<E> condition) {
final List<E> result = new ArrayList<>();
final Component[] children = aRoot.getComponents();
for (final Component c : children) {
if (aClass.isInstance(c) && condition.test(aClass.cast(c))) {
result.add(aClass.cast(c));
}
if (c instanceof Container) {
result.addAll(getAllChildrenOfClass((Container) c, aClass, condition));
}
}
return result;
}
因此，您的字段
可能需要是二维数组，例如字段[][]字段=新字段[9][9]。这样，您就可以访问给定面板（第一维）的字段（第二维），即fields[pane][field]
。显然，在for循环中，需要正确初始化字段数组，例如，字段[I]=新字段[9]
；似乎文本字段应该替换为一个JTable
（但关于它们的用途，我没有足够的细节来确定）。一般提示：1）为了更快地获得更好的帮助，请添加或。2） public class Frame扩展JFrame{
这里没有扩展JFrame
的好例子。只需使用一个实例即可。
/**
* Searches for all children of the given component which are instances of the given class.
*
* @param aRoot start object for search. May not be null.
* @param aClass class to search. May not be null.
* @param <E> class of component.
* @return list of all children of the given component which are instances of the given class. Never null.
*/
public static <E> List<E> getAllChildrenOfClass(Container aRoot, Class<E> aClass) {
return getAllChildrenOfClass(aRoot, aClass, e -> true);
}
/**
* Searches for all children of the given component which are instances of the given class and satisfies the given condition.
*
* @param aRoot start object for search. May not be null.
* @param aClass class to search. May not be null.
* @param condition condition to be satisfied. May not be null.
* @param <E> class of component.
* @return list of all children of the given component which are instances of the given class. Never null.
*/
public static <E> List<E> getAllChildrenOfClass(Container aRoot, Class<E> aClass, Predicate<E> condition) {
final List<E> result = new ArrayList<>();
final Component[] children = aRoot.getComponents();
for (final Component c : children) {
if (aClass.isInstance(c) && condition.test(aClass.cast(c))) {
result.add(aClass.cast(c));
}
if (c instanceof Container) {
result.addAll(getAllChildrenOfClass((Container) c, aClass, condition));
}
}
return result;
}
getAllChildrenOfClass(getContentPane(), JTextField.class).forEach(tf -> tf.setText("My text"));