我正在编写一个GUI Builder,希望用户能够更改他构建的GUI的LookAndFeel。 LookAndFeel仅应在编辑器区域内的Components进行更改。应用程序的其余部分应保留在SystemLookAndFeel中。
很大的问题是,LookAndFeel是作为Singleton实现的,并且在应用程序过程中多次更改LookAndFeel会导致很多错误。
我开始尝试Buttons:
我尝试将ButtonUI设置为MetalButtonUI,但它们无法正确呈现。因此,我调试了JButton的默认paintComponent方法,并看到ButtonUI仍然需要UIDefaults,因为它们是WindowsUIDefaults,所以它们并不完整。
我当前的解决方案是设置MetalLookAndFeel,保存UIDefaults,然后将LookAndFeel更改为SystemLookAndFeel并保存这些UIDefaults,并且每次在编辑器中绘制一个Button时,都会交换UIDefaults。
这是代码:
public class MainClass{
public static Hashtable systemUI;
public static Hashtable metalUI;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
metalUI = new Hashtable();
metalUI.putAll(UIManager.getDefaults());
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
systemUI = new Hashtable();
systemUI.putAll(UIManager.getDefaults());
} catch (Exception e) {
e.printStackTrace();
}
/* ...
* Generate JFrame and other stuff
* ...
*/
}
});
}
}
public class MyButton extends JButton {
public MyButton(String text) {
super(text);
ui = MetalButtonUI.createUI(this);
}
@Override public synchronized void paintComponent(Graphics g) {
UIManager.getDefaults().putAll(Application.metalUI);
super.paintComponent(g);
UIManager.getDefaults().putAll(Application.systemUI);
}
}
如您所见,here结果非常好。左侧是MetalLaF,其外观应在右侧,右侧是如何在应用程序中呈现的。渐变正确绘制,但“边框”和“字体”却不正确。
因此,我需要知道为什么不是LaF的所有元素都被应用到Button以及如何解决。
--
编辑:
我找到了一个丑陋的解决方案。创建Button之前,必须更改LookAndFeel,因为Graphics对象将在构造方法中创建。在调用超级构造函数之后,您可以将LookAndFeel改回来。
接下来,您需要在绘制/重新绘制组件之前更改LookAndFeel。我唯一能使它工作的地方是在super被调用之前在paintComponent中。您可以在调用super之后将其改回。
码:
import javax.swing.*;
import javax.swing.plaf.metal.MetalButtonUI;
import java.awt.*;
public class MainClass {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
JFrame f = new JFrame("Test");
f.setDefaultCloseOperation(f.getExtendedState() | JFrame.EXIT_ON_CLOSE);
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
} catch (Exception ex) {
}
f.setLayout(new FlowLayout());
f.add(new MyButton("MetalButton"));
f.add(new JButton("SystemButton"));
f.pack();
f.setVisible(true);
}
});
}
}
class MyButton extends JButton {
public MyButton(String text) {
super(text);
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
}
ui = MetalButtonUI.createUI(this);
}
@Override public synchronized void paintComponent(Graphics g) {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
super.paintComponent(g);
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
}
}
}
编辑2:
除非绝对必要,否则请勿使用此功能!
这是非常不稳定的。经过大量测试,当我只交换UIDefaults而不是整个LookAndFeel时,发现它的bug较少,但是我不建议您进行任何此类操作。
编辑3:
我发现最好的解决方案是使用JavaFX作为GUI。我将一个swing节点插入了Editor区域,现在可以根据需要多次修改swing组件的外观,而没有任何明显的副作用。
兰特:
如果要修改应用程序的样式,总是可以选择JavaFX。 CSS使它变得尽可能简单,没有任何副作用!
非常感谢
乔尼
最佳答案
免责声明
Swing的Look And Feel并非在首次启动后就进行了切换,实际上这是一种可能的怪异副作用。在正常情况下,某些外观和某些组件可能不喜欢您这样做,并且可能无法正常运行。
可能的解决方案
出于对智能的热爱,不要在paintComponent方法中更改UI默认设置(不要从任何paint
方法中更改UI的状态,只绘画当前状态),这只是要求无尽的麻烦。
相反,在需要时使用UIManager.setLookAndFeel(,,,)
和SwingUtiltiies#updateComponentTreeUI
并传入最顶层的容器
例如...
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultComboBoxModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class LookAndFeelSwitcher {
public static void main(String[] args) {
new LookAndFeelSwitcher();
}
public LookAndFeelSwitcher() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.insets = new Insets(2, 2, 2, 2);
add(new JLabel("I have a bad feeling about this"), gbc);
add(new JTextField("When this blows up in your face, don't blame me"), gbc);
UIManager.LookAndFeelInfo[] lafs = UIManager.getInstalledLookAndFeels();
DefaultComboBoxModel model = new DefaultComboBoxModel(lafs);
JComboBox cb = new JComboBox(model);
cb.setRenderer(new LookAndFeelInfoListCellRenderer());
add(cb, gbc);
String name = UIManager.getLookAndFeel().getName();
for (int index = 0; index < model.getSize(); index++) {
UIManager.LookAndFeelInfo info = (UIManager.LookAndFeelInfo) model.getElementAt(index);
if (info.getName().equals(name)) {
model.setSelectedItem(info);
break;
}
}
cb.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
UIManager.LookAndFeelInfo info = (UIManager.LookAndFeelInfo) cb.getSelectedItem();
String className = info.getClassName();
try {
UIManager.setLookAndFeel(className);
SwingUtilities.updateComponentTreeUI(SwingUtilities.windowForComponent(TestPane.this));
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
}
});
}
public class LookAndFeelInfoListCellRenderer extends DefaultListCellRenderer {
@Override
public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
if (value instanceof UIManager.LookAndFeelInfo) {
UIManager.LookAndFeelInfo info = (UIManager.LookAndFeelInfo) value;
value = info.getName();
}
return super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
}
}
}
}
关于java - 通过交换UIDefaults更改外观,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/33617713/