使用 Java 7+ 更容易，使用 Java 6，您需要使用私有 API com.sun.awt.AWTUtilities
为此，我编写了一个实用程序类，使其更易于使用。它使用反射来确定是否可以实际调用，以防您使用低于 6u10 的 Java 版本
public static boolean supportsPerAlphaPixel() {
boolean support = false;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
support = true;
} catch (Exception exp) {
}
return support;
}
public static void setOpaque(Window window, boolean opaque) {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpaque", Window.class, boolean.class);
method.invoke(null, window, opaque);
}
} catch (Exception exp) {
}
}
public static void setOpacity(Window window, float opacity) {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpacity", Window.class, float.class);
method.invoke(null, window, opacity);
}
} catch (Exception exp) {
exp.printStackTrace();
}
}
public static float getOpacity(Window window) {
float opacity = 1f;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("getWindowOpacity", Window.class);
Object value = method.invoke(null, window);
if (value != null && value instanceof Float) {
opacity = ((Float) value).floatValue();
}
}
} catch (Exception exp) {
exp.printStackTrace();
}
return opacity;
}
不透明
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Window;
import java.lang.reflect.Method;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
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.setUndecorated(true);
setOpaque(frame, false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setOpaque(false);
setBorder(new LineBorder(Color.RED));
setLayout(new GridBagLayout());
add(new JLabel("Look no hands"));
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public static boolean supportsPerAlphaPixel() {
boolean support = false;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
support = true;
} catch (Exception exp) {
}
return support;
}
public static void setOpaque(Window window, boolean opaque) {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpaque", Window.class, boolean.class);
method.invoke(null, window, opaque);
}
} catch (Exception exp) {
}
}
public static void setOpacity(Window window, float opacity) {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpacity", Window.class, float.class);
method.invoke(null, window, opacity);
}
} catch (Exception exp) {
exp.printStackTrace();
}
}
public static float getOpacity(Window window) {
float opacity = 1f;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("getWindowOpacity", Window.class);
Object value = method.invoke(null, window);
if (value != null && value instanceof Float) {
opacity = ((Float) value).floatValue();
}
}
} catch (Exception exp) {
exp.printStackTrace();
}
return opacity;
}
}
透明
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.Window;
import java.lang.reflect.Method;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
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.setUndecorated(true);
setOpacity(frame, 0.5f);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
add(new JLabel("Look no hands"));
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public static boolean supportsPerAlphaPixel() {
boolean support = false;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
support = true;
} catch (Exception exp) {
}
return support;
}
public static void setOpaque(Window window, boolean opaque) {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpaque", Window.class, boolean.class);
method.invoke(null, window, opaque);
}
} catch (Exception exp) {
}
}
public static void setOpacity(Window window, float opacity) {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpacity", Window.class, float.class);
method.invoke(null, window, opacity);
}
} catch (Exception exp) {
exp.printStackTrace();
}
}
public static float getOpacity(Window window) {
float opacity = 1f;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("getWindowOpacity", Window.class);
Object value = method.invoke(null, window);
if (value != null && value instanceof Float) {
opacity = ((Float) value).floatValue();
}
}
} catch (Exception exp) {
exp.printStackTrace();
}
return opacity;
}
}
现在，在您完全了解框架“无边界”之前，这是为了让它工作，但是，它可能不适用于所有平台（如 MacOS），它需要您使用外观和感觉框架边框（例如金属），这不是特别令人愉快...