动态添加的JPanels没有出现在Swing中 [英] Dynamically added JPanels are not showing up in Swing
问题描述
这是我的代码。显示先前设计的框架(添加了面板)时没有问题。我在动态地向空JFrame添加面板时遇到此问题。
Here's my code. I have no problem when showing up the previously designed frames (with panels added). I get this issue when adding panels to an empty JFrame dynamically.
package com.mytunes.controllers;
import com.mytunes.views.*;
import com.mytunes.views.panels.*;
import java.awt.BorderLayout;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.WindowConstants;
public class GUIController {
ArrayList<JFrame> displayFrames = new ArrayList<JFrame>();
JPanel displayPanel;
HeaderPanel headerPanel = new HeaderPanel();
FooterPanel footerPanel = new FooterPanel();
public int showFrame(String frameName, Object controller){
Class c;
Constructor ctr;
int lastFrame = -1;
try {
// call a class dynamically
c = Class.forName("com.mytunes.views.frames." + frameName + "Frame");
// calll a constructor of a class
ctr = c.getConstructor(SessionController.class);
// instantiate dynamically created class
displayFrames.add((JFrame) ctr.newInstance(controller));
// get the index of frame just added
lastFrame = displayFrames.size()-1;
displayFrames.get(lastFrame).setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
displayFrames.get(lastFrame).pack();
displayFrames.get(lastFrame).setLocationRelativeTo(null);
// hide it by default.
displayFrames.get(displayFrames.size()-1).setVisible(false);
} catch (InstantiationException ex) {
Logger.getLogger(GUIController.class.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
Logger.getLogger(GUIController.class.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalArgumentException ex) {
Logger.getLogger(GUIController.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvocationTargetException ex) {
Logger.getLogger(GUIController.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchMethodException ex) {
Logger.getLogger(GUIController.class.getName()).log(Level.SEVERE, null, ex);
} catch (SecurityException ex) {
Logger.getLogger(GUIController.class.getName()).log(Level.SEVERE, null, ex);
} catch (ClassNotFoundException ex) {
JOptionPane.showMessageDialog(null, "Error while loading class 'com.mytunes.view.frames." + frameName + "'" );
}
System.out.println(lastFrame);
return lastFrame;
}
//-------------show panels --------------//
public void showOperator(String frame, Object controller){
// this works fine! this frame is already having Panels
int f = showFrame(frame, controller);
displayFrames.get(f).setVisible(true);
}
public void showEnterPIN(String frame, Object controller){
int f = showFrame(frame, controller);
displayFrames.get(f).getContentPane().add(new EnterPINPanel(), BorderLayout.CENTER);
displayFrames.get(f).setVisible(true);
// Try every following ways to show the "Dynamically added" panels
// displayFrames.get(f).getContentPane().removeAll();
// displayFrames.get(f).getContentPane().invalidate();
// displayFrames.get(f).getContentPane().add(new EnterPINPanel(), BorderLayout.PAGE_START);
// displayFrames.get(f).getContentPane().validate();
// displayFrames.get(f).pack();
// displayFrames.get(f).setVisible(true);
}
}
感谢某人可以为我发现这个问题。谢谢。
Appreciate if someone can spot this issue out for me. Thanks.
推荐答案
如果将组件添加到容器中,则需要告诉容器的布局管理器布置它们包含的所有组件通过调用 revalidate()
,然后有时在容器上调用 repaint();
。所以,像... ...
If you add a component to a container you need to tell the container's layout managers to layout all the components they contain by calling revalidate()
and then by sometimes calling repaint();
on the container. So, something like...
JPanel contentPane = (JPanel)displayFrames.get(f).getContentPane();
contentPane.add(new EnterPINPanel(), BorderLayout.CENTER);
contentPane.revalidate();
contentPane.repaint();
话虽如此,您的应用程序设计看起来有点不同。你真的使用JFrames的ArrayList吗?大多数真实世界的应用程序不使用一堆单独的窗口,而是在一个主窗口中交换显示,你可以通过使用一个JFrame和通过CardLayout交换视图来使用Swing做类似的事情。
Having said this, your application design looks a bit different. Do you really use an ArrayList of JFrames? Most real-world applications don't use a bunch of separate windows but rather swap displays in one main window, and you can do a similar thing with Swing by using just one JFrame and swap views via a CardLayout.
编辑2
如果您尝试怎么办:
Edit 2
What if you try:
int f = showFrame(frame, controller);
JPanel contentPane = (JPanel)displayFrames.get(f).getContentPane();
contentPane.removeAll();
contentPane.setLayout(new BorderLayout()); // just to be sure
contentPane.add(headerPanel, BorderLayout.PAGE_START);
contentPane.add(new EnterPINPanel(), BorderLayout.CENTER);
contentPane.add(footerPanel, BorderLayout.PAGE_END);
contentPane.revalidate(); // *** note that it's **re**validate
contentPane.repaint();
displayFrames.get(f).setVisible(true);
再次,如果这没有帮助,那么你应该创建并发布简短,自包含,正确(可编译),示例或SSCCE
Again, if this doesn't help, then you should create and post a "Short, Self Contained, Correct (Compilable), Example" or SSCCE
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