[英]How to change card layout panels from another panel?
我google了很多,沒有找到解決方案。 我想應該有 java 高手來幫助我...
這是我的初始化方法:
private void initialize() {
this.setSize(750, 480);
this.setContentPane(getJContentPane());
this.setTitle("Registration");
JPanel topPane = new TopPane();
this.getContentPane().add(topPane,BorderLayout.PAGE_START);
cards=new JPanel(new CardLayout());
cards.add(step0(),"step0");
cards.add(step1(),"step1");
cards.add(step2(),"step2");
this.getContentPane().add(cards,BorderLayout.CENTER);
}
public JPanel step2(){
EnumMap<DPFPFingerIndex,DPFPTemplate> template = new EnumMap<DPFPFingerIndex, DPFPTemplate>(DPFPFingerIndex.class);
JPanel enrol = new Enrollment(template,2);
return enrol;
}
public JPanel step0(){
JPanel userAgree = new UserAgreement();
return userAgree;
}
public JPanel step1(){
JPanel userInfo = new UserInformation();
return userInfo;
}
public JPanel getCards(){
return cards;
}
這是另一個步驟 0 JPanel 的方法:
jButtonAgree.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent e) {
Registration reg = new Registration();
LayoutManager cards = reg.getCards().getLayout();
((CardLayout) cards).show(reg.getCards(),"step1");
}
});
根本沒有反應,我嘗試重新驗證,重新粉刷和其他工作人員......不起作用......任何人都在這里得到任何解決方案!
這一切都是為了向外界公開正確的方法和常量字符串,以允許 class 自身交換視圖。 例如,為您的第一個 class 提供一個稱為 cardlayout 的私有 CardLayout 字段和一個稱為卡(持卡人 JPanel)的私有 JPanel 字段,以及一些用於將您的卡 JPanel 添加到卡容器的公共字符串常量。 還給它一個公共方法,比如稱為public void swapView(String key)
,它允許外部類交換卡片......像這樣:
// code corrected
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Registration extends JPanel {
// use these same constants as button texts later
private static final Dimension PREF_SIZE = new Dimension(450, 300);
public static final String USER_AGREEMENT = "User Agreement";
public static final String USER_INFO = "User Information";
public static final String ENROLLMENT = "Enrollment";
// we'll extract them from this array
public static final String[] KEY_TEXTS = {USER_AGREEMENT, USER_INFO, ENROLLMENT};
private CardLayout cardlayout = new CardLayout();
private JPanel cards = new JPanel(cardlayout);
public Registration() {
cards.add(createUserAgreePanel(), USER_AGREEMENT);
cards.add(createUserInfoPanel(), USER_INFO);
cards.add(createEnrollmentPanel(), ENROLLMENT);
setLayout(new BorderLayout());
add(cards, BorderLayout.CENTER);
}
@Override
public Dimension getPreferredSize() {
return PREF_SIZE;
}
private JPanel createEnrollmentPanel() {
JPanel enrol = new JPanel();
enrol.add(new JLabel("Enrollment"));
return enrol;
}
private JPanel createUserAgreePanel() {
JPanel userAgree = new JPanel();
userAgree.add(new JLabel("User Agreement"));
return userAgree;
}
private JPanel createUserInfoPanel() {
JPanel userInfo = new JPanel();
userInfo.add(new JLabel("User Information"));
return userInfo;
}
public void swapView(String key) {
cardlayout.show(cards, key);
}
}
然后外部 class 可以通過調用此 class 的可視化實例上的 swapView 來交換視圖,並傳入適當的鍵字符串,例如在本例中為 CardTest.USER_INFO 以顯示用戶信息 JPanel。
現在您對我通過注釋指出的這段代碼有疑問:
jButtonAgree.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent e) {
Registration reg = new Registration(); // **** HERE *****
LayoutManager cards = reg.getCards().getLayout();
((CardLayout) cards).show(reg.getCards(),"step1");
}
});
在該行上,您正在創建一個新的注冊 object,它可能與在 GUI 上可視化的那個完全無關,因此在這個新的 object 上調用方法對當前查看的 gui 絕對沒有影響。 相反,您需要獲取對查看的注冊 object 的引用,也許通過給這個 class 一個 getRegistration 方法,然后調用它的方法,如下所示:
class OutsideClass {
private Registration registration;
private JButton jButtonAgree = new JButton("Agree");
public OutsideClass() {
jButtonAgree.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// make sure registration reference has been obtained first!
if (registration != null) {
registration.swapView(Registration.USER_AGREEMENT);
}
}
});
}
// here I allow the calling class to pass a reference to the visualized
// Registration instance.
public void setRegistration(Registration registration) {
this.registration = registration;
}
}
例如:
@SuppressWarnings("serial")
class ButtonPanel extends JPanel {
private Registration registration;
public ButtonPanel() {
setLayout(new GridLayout(1, 0, 10, 0));
// go through String array making buttons
for (final String keyText : Registration.KEY_TEXTS) {
JButton btn = new JButton(keyText);
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (registration != null) {
registration.swapView(keyText);
}
}
});
add(btn);
}
}
public void setRegistration(Registration registration) {
this.registration = registration;
}
}
以及驅動這一切的 MainClass
class MainClass extends JPanel {
public MainClass() {
Registration registration = new Registration();
ButtonPanel buttonPanel = new ButtonPanel();
buttonPanel.setRegistration(registration);
buttonPanel.setBorder(BorderFactory.createTitledBorder("Button Panel"));
registration.setBorder(BorderFactory.createTitledBorder("Registration Panel"));
setLayout(new BorderLayout());
add(registration, BorderLayout.CENTER);
add(buttonPanel, BorderLayout.SOUTH);
}
private static void createAndShowUI() {
JFrame frame = new JFrame("Registration");
frame.getContentPane().add(new MainClass());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
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