将自定义对象从嵌入式 FX (JFXPanel) 拖放到 Swing
Custom object drag-and-drop from embedded FX (JFXPanel) to Swing
这个问题是 到 的跟进问题。
我正在为 Swing 应用程序开发一个插件，该应用程序将 JavaFX 用于某些图形用户界面。我们添加了拖放功能以改善用户体验。首先，我们为 Scene 使用外部 JavaFX window (Stage)，现在我们想通过 JFXPanel 将其直接嵌入到 Swing 应用程序中].
现在，奇怪的是，在 Stage 或 [=14] 中加载完全相同的 Scene 似乎对拖放有很大影响=].
我在尝试将某些具有自定义 MIME 类型的自定义 Java 对象（以序列化形式）从 JavaFX 应用程序拖到 Swing 应用程序时遇到了一些问题。但是，我的问题在我上面提到的问题中得到了解决。现在，使用嵌入式JavaFX应用程序，我遇到了一些新问题，所以我想问问是否有人有类似的问题或知道这种情况的解决方案。
我写了一个 MVCE，它是一个简单的 Java 应用程序，一侧支持拖动 JFXPanel，另一侧支持拖放 JPanel：
public class MyApp {
public static final DataFormat FORMAT = new DataFormat(
// this works fine in a separate window
//"JAVA_DATAFLAVOR:application/x-my-mime-type; class=java.lang.String",
"application/x-my-mime-type; class=java.lang.String");
public static final DataFlavor FLAVOR;
static {
try {
FLAVOR = new DataFlavor("application/x-my-mime-type; class=java.lang.String");
} catch (ClassNotFoundException ex) {
throw new RuntimeException(ex);
}
}
public static void main(String[] args) {
new MyApp().run();
}
private void run() {
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(1, 2));
frame.add(buildFX());
frame.add(buildSwing());
frame.setSize(300, 300);
frame.setVisible(true);
}
private JFXPanel buildFX() {
BorderPane parent = new BorderPane();
parent.setOnDragDetected(event -> {
Dragboard dragboard = parent.startDragAndDrop(TransferMode.COPY);
ClipboardContent content = new ClipboardContent();
content.put(FORMAT, "Test");
dragboard.setContent(content);
event.consume();
});
JFXPanel panel = new JFXPanel();
panel.setScene(new Scene(parent));
return panel;
}
@SuppressWarnings("serial")
private JPanel buildSwing() {
JPanel panel = new JPanel();
panel.setBackground(Color.ORANGE);
panel.setTransferHandler(new TransferHandler() {
@Override
public boolean canImport(TransferSupport support) {
return support.isDataFlavorSupported(FLAVOR);
}
@Override
public boolean importData(TransferSupport support) {
if (!canImport(support)) return false;
try {
String data = (String) support.getTransferable().getTransferData(FLAVOR);
System.out.println(data);
return true;
} catch (UnsupportedFlavorException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
});
return panel;
}
}
根据另一个问题的回答，在 DataFormat 中使用前缀 JAVA_DATAFLAVOR: 是 Swing 正确处理 MIME 类型所必需的。但是，当在 JFXPanel（示例中禁用）中使用这样的 DataFormat 时，似乎 Java 在从 FX 应用程序拖动时尝试构建 DataFlavor 但失败了解析带有前缀的 MIME 类型：
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: failed to parse:JAVA_DATAFLAVOR:application/x-my-mime-type; class=java.lang.String
at java.awt.datatransfer.DataFlavor.<init>(Unknown Source)
at javafx.embed.swing.SwingDnD$DnDTransferable.getTransferDataFlavors(SwingDnD.java:394)
at sun.awt.datatransfer.DataTransferer.getFormatsForTransferable(Unknown Source)
at sun.awt.dnd.SunDragSourceContextPeer.startDrag(Unknown Source)
at java.awt.dnd.DragSource.startDrag(Unknown Source)
at java.awt.dnd.DragSource.startDrag(Unknown Source)
at java.awt.dnd.DragGestureEvent.startDrag(Unknown Source)
at javafx.embed.swing.SwingDnD.startDrag(SwingDnD.java:280)
at javafx.embed.swing.SwingDnD.lambda$null(SwingDnD.java:247)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access0(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
只使用纯MIME类型，没有前缀，拖放操作有效，我什至可以收到正确的DataFlavor（java.awt.datatransfer.DataFlavor[mimetype=application/x-my-mime-type;representationclass=java.lang.String]），但拖放的数据总是null。正如在另一个问题中看到的那样，使用第二种方法和两个分开的 windows，我什至无法收到 DataFlavor，但现在它以某种方式工作到这个有限的点。
可能对传输的工作方式存在一些误解。
尝试直接将传输数据作为字符串检索可能适用于 "text/plain" 或其他标准文本类型，并且正如您所注意到的，对于自定义未注册类型的特定情况有一些怪癖。但我认为自定义解决方法的努力是不合理的。
由于您完全控制了自定义 MIME 类型的内容结构以及同一应用程序中数据生产者和消费者的两端，我建议不要处理依赖于内部工具包实现的前缀或 class映射。可能更好的方法是只定义您的 MIME 类型而没有不相关的元数据和格式错误的前缀（因为它应该是）。
定义一个 "application/x-my-mime" 类型并正确解码数据就足够了。
示例 1（序列化数据）
下面根据您的示例进行了更正，应该可以将数据很好地放入 Java 8 中的 Swing 框架。
package jfxtest;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.datatransfer.DataFlavor;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.util.Collections;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.input.DataFormat;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.BorderPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
public class MyApp {
final static String MY_MIME_TYPE = "application/x-my-mime";
public static final DataFormat FORMAT = new DataFormat(MY_MIME_TYPE);
public static final DataFlavor FLAVOR = new DataFlavor(MY_MIME_TYPE, "My Mime Type");
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
Collections.singletonMap(FORMAT, "Test"));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
Object transferred = new ObjectInputStream(in).readObject();
System.out.println("transferred: " + transferred + " (" + transferred.getClass() + ")");
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
public static void main(String[] args) {
new MyApp().run();
}
private void run() {
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(1, 2));
frame.add(buildSwing());
SwingUtilities.invokeLater(() -> {
frame.add(buildFX());
});
frame.setSize(300, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private JFXPanel buildFX() {
BorderPane parent = new BorderPane();
parent.setOnDragDetected(event -> {
startDrag(parent);
event.consume();
});
JFXPanel panel = new JFXPanel();
panel.setScene(new Scene(parent));
return panel;
}
private JPanel buildSwing() {
JPanel panel = new JPanel();
panel.setBackground(Color.ORANGE);
panel.setTransferHandler(new TransferHandler() {
private static final long serialVersionUID = 1L;
@Override
public boolean canImport(TransferSupport support) {
return support.isDataFlavorSupported(FLAVOR);
}
@Override
public boolean importData(TransferSupport support) {
if (canImport(support)) {
return processData(support);
}
return false;
}
});
return panel;
}
}
输出：transferred: Test (class java.lang.String)
这里的重要摘录是：
...
final static String MY_MIME_TYPE = "application/x-my-mime";
public static final DataFormat FORMAT = new DataFormat(MY_MIME_TYPE);
public static final DataFlavor FLAVOR = new DataFlavor(MY_MIME_TYPE, "My Mime Type");
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
Collections.singletonMap(FORMAT, "Test"));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
Object transferred = new ObjectInputStream(in).readObject();
System.out.println("transferred: " + transferred + " (" + transferred.getClass() + ")");
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
...
请注意，出于说明目的，数据检索过于简单，对于实际应用程序，可能需要添加更严格的流读取、处理错误等。
示例 2（带有文本的自定义 mime）
第一个示例传输一个序列化对象（这通常是一件好事和简单的事情，因为您可以传输任何可序列化的东西，但是很难 transfer/accept，比如，第 3 方 JSON） .在不太可能的情况下，当您希望为自定义 MIME 而不是序列化对象生成真实文本或其他任意内容时，下面的内容应该可以完成工作：
package jfxtest;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.datatransfer.DataFlavor;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.input.DataFormat;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.BorderPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
public class MyApp {
final static String MY_MIME_TYPE = "application/x-my-mime";
public static final DataFormat FORMAT = new DataFormat(MY_MIME_TYPE);
public static final DataFlavor FLAVOR = new DataFlavor(MY_MIME_TYPE, "My Mime Type");
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
// put a ByteBuffer to transfer the content unaffected
Collections.singletonMap(FORMAT, StandardCharsets.UTF_8.encode("Test")));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
byte[] textBytes = new byte[in.available()];
in.read(textBytes);
String transferred = new String(textBytes, StandardCharsets.UTF_8);
System.out.println("transferred text: " + transferred);
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
public static void main(String[] args) {
new MyApp().run();
}
private void run() {
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(1, 2));
frame.add(buildSwing());
SwingUtilities.invokeLater(() -> {
frame.add(buildFX());
});
frame.setSize(300, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private JFXPanel buildFX() {
BorderPane parent = new BorderPane();
parent.setOnDragDetected(event -> {
startDrag(parent);
event.consume();
});
JFXPanel panel = new JFXPanel();
panel.setScene(new Scene(parent));
return panel;
}
private JPanel buildSwing() {
JPanel panel = new JPanel();
panel.setBackground(Color.ORANGE);
panel.setTransferHandler(new TransferHandler() {
private static final long serialVersionUID = 1L;
@Override
public boolean canImport(TransferSupport support) {
return support.isDataFlavorSupported(FLAVOR);
}
@Override
public boolean importData(TransferSupport support) {
if (canImport(support)) {
return processData(support);
}
return false;
}
});
return panel;
}
}
输出：transferred text: Test
这里最重要的部分是：
...
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
// put a ByteBuffer to transfer the content unaffected
Collections.singletonMap(FORMAT, StandardCharsets.UTF_8.encode("Test")));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
byte[] textBytes = new byte[in.available()];
in.read(textBytes);
String transferred = new String(textBytes, StandardCharsets.UTF_8);
System.out.println("transferred text: " + transferred);
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
...
再次说明，这里的流、错误等处理很简单。
需要注意的一件事是，还有一个预定义的 "application/x-java-serialized-object" (DataFlavor.javaSerializedObjectMimeType) 用于更通用和更容易的反序列化。但长期自定义 MIME 似乎更灵活，整体处理起来更直接。
这个问题是 到
我正在为 Swing 应用程序开发一个插件，该应用程序将 JavaFX 用于某些图形用户界面。我们添加了拖放功能以改善用户体验。首先，我们为 Scene 使用外部 JavaFX window (Stage)，现在我们想通过 JFXPanel 将其直接嵌入到 Swing 应用程序中].
现在，奇怪的是，在 Stage 或 [=14] 中加载完全相同的 Scene 似乎对拖放有很大影响=].
我在尝试将某些具有自定义 MIME 类型的自定义 Java 对象（以序列化形式）从 JavaFX 应用程序拖到 Swing 应用程序时遇到了一些问题。但是，我的问题在我上面提到的问题中得到了解决。现在，使用嵌入式JavaFX应用程序，我遇到了一些新问题，所以我想问问是否有人有类似的问题或知道这种情况的解决方案。
我写了一个 MVCE，它是一个简单的 Java 应用程序，一侧支持拖动 JFXPanel，另一侧支持拖放 JPanel：
public class MyApp {
public static final DataFormat FORMAT = new DataFormat(
// this works fine in a separate window
//"JAVA_DATAFLAVOR:application/x-my-mime-type; class=java.lang.String",
"application/x-my-mime-type; class=java.lang.String");
public static final DataFlavor FLAVOR;
static {
try {
FLAVOR = new DataFlavor("application/x-my-mime-type; class=java.lang.String");
} catch (ClassNotFoundException ex) {
throw new RuntimeException(ex);
}
}
public static void main(String[] args) {
new MyApp().run();
}
private void run() {
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(1, 2));
frame.add(buildFX());
frame.add(buildSwing());
frame.setSize(300, 300);
frame.setVisible(true);
}
private JFXPanel buildFX() {
BorderPane parent = new BorderPane();
parent.setOnDragDetected(event -> {
Dragboard dragboard = parent.startDragAndDrop(TransferMode.COPY);
ClipboardContent content = new ClipboardContent();
content.put(FORMAT, "Test");
dragboard.setContent(content);
event.consume();
});
JFXPanel panel = new JFXPanel();
panel.setScene(new Scene(parent));
return panel;
}
@SuppressWarnings("serial")
private JPanel buildSwing() {
JPanel panel = new JPanel();
panel.setBackground(Color.ORANGE);
panel.setTransferHandler(new TransferHandler() {
@Override
public boolean canImport(TransferSupport support) {
return support.isDataFlavorSupported(FLAVOR);
}
@Override
public boolean importData(TransferSupport support) {
if (!canImport(support)) return false;
try {
String data = (String) support.getTransferable().getTransferData(FLAVOR);
System.out.println(data);
return true;
} catch (UnsupportedFlavorException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
});
return panel;
}
}
根据另一个问题的回答，在 DataFormat 中使用前缀 JAVA_DATAFLAVOR: 是 Swing 正确处理 MIME 类型所必需的。但是，当在 JFXPanel（示例中禁用）中使用这样的 DataFormat 时，似乎 Java 在从 FX 应用程序拖动时尝试构建 DataFlavor 但失败了解析带有前缀的 MIME 类型：
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: failed to parse:JAVA_DATAFLAVOR:application/x-my-mime-type; class=java.lang.String
at java.awt.datatransfer.DataFlavor.<init>(Unknown Source)
at javafx.embed.swing.SwingDnD$DnDTransferable.getTransferDataFlavors(SwingDnD.java:394)
at sun.awt.datatransfer.DataTransferer.getFormatsForTransferable(Unknown Source)
at sun.awt.dnd.SunDragSourceContextPeer.startDrag(Unknown Source)
at java.awt.dnd.DragSource.startDrag(Unknown Source)
at java.awt.dnd.DragSource.startDrag(Unknown Source)
at java.awt.dnd.DragGestureEvent.startDrag(Unknown Source)
at javafx.embed.swing.SwingDnD.startDrag(SwingDnD.java:280)
at javafx.embed.swing.SwingDnD.lambda$null(SwingDnD.java:247)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access0(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
只使用纯MIME类型，没有前缀，拖放操作有效，我什至可以收到正确的DataFlavor（java.awt.datatransfer.DataFlavor[mimetype=application/x-my-mime-type;representationclass=java.lang.String]），但拖放的数据总是null。正如在另一个问题中看到的那样，使用第二种方法和两个分开的 windows，我什至无法收到 DataFlavor，但现在它以某种方式工作到这个有限的点。
可能对传输的工作方式存在一些误解。
尝试直接将传输数据作为字符串检索可能适用于 "text/plain" 或其他标准文本类型，并且正如您所注意到的，对于自定义未注册类型的特定情况有一些怪癖。但我认为自定义解决方法的努力是不合理的。
由于您完全控制了自定义 MIME 类型的内容结构以及同一应用程序中数据生产者和消费者的两端，我建议不要处理依赖于内部工具包实现的前缀或 class映射。可能更好的方法是只定义您的 MIME 类型而没有不相关的元数据和格式错误的前缀（因为它应该是）。
定义一个 "application/x-my-mime" 类型并正确解码数据就足够了。
示例 1（序列化数据）
下面根据您的示例进行了更正，应该可以将数据很好地放入 Java 8 中的 Swing 框架。
package jfxtest;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.datatransfer.DataFlavor;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.util.Collections;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.input.DataFormat;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.BorderPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
public class MyApp {
final static String MY_MIME_TYPE = "application/x-my-mime";
public static final DataFormat FORMAT = new DataFormat(MY_MIME_TYPE);
public static final DataFlavor FLAVOR = new DataFlavor(MY_MIME_TYPE, "My Mime Type");
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
Collections.singletonMap(FORMAT, "Test"));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
Object transferred = new ObjectInputStream(in).readObject();
System.out.println("transferred: " + transferred + " (" + transferred.getClass() + ")");
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
public static void main(String[] args) {
new MyApp().run();
}
private void run() {
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(1, 2));
frame.add(buildSwing());
SwingUtilities.invokeLater(() -> {
frame.add(buildFX());
});
frame.setSize(300, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private JFXPanel buildFX() {
BorderPane parent = new BorderPane();
parent.setOnDragDetected(event -> {
startDrag(parent);
event.consume();
});
JFXPanel panel = new JFXPanel();
panel.setScene(new Scene(parent));
return panel;
}
private JPanel buildSwing() {
JPanel panel = new JPanel();
panel.setBackground(Color.ORANGE);
panel.setTransferHandler(new TransferHandler() {
private static final long serialVersionUID = 1L;
@Override
public boolean canImport(TransferSupport support) {
return support.isDataFlavorSupported(FLAVOR);
}
@Override
public boolean importData(TransferSupport support) {
if (canImport(support)) {
return processData(support);
}
return false;
}
});
return panel;
}
}
输出：transferred: Test (class java.lang.String)
这里的重要摘录是：
...
final static String MY_MIME_TYPE = "application/x-my-mime";
public static final DataFormat FORMAT = new DataFormat(MY_MIME_TYPE);
public static final DataFlavor FLAVOR = new DataFlavor(MY_MIME_TYPE, "My Mime Type");
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
Collections.singletonMap(FORMAT, "Test"));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
Object transferred = new ObjectInputStream(in).readObject();
System.out.println("transferred: " + transferred + " (" + transferred.getClass() + ")");
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
...
请注意，出于说明目的，数据检索过于简单，对于实际应用程序，可能需要添加更严格的流读取、处理错误等。
示例 2（带有文本的自定义 mime）
第一个示例传输一个序列化对象（这通常是一件好事和简单的事情，因为您可以传输任何可序列化的东西，但是很难 transfer/accept，比如，第 3 方 JSON） .在不太可能的情况下，当您希望为自定义 MIME 而不是序列化对象生成真实文本或其他任意内容时，下面的内容应该可以完成工作：
package jfxtest;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.datatransfer.DataFlavor;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.input.DataFormat;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.BorderPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
public class MyApp {
final static String MY_MIME_TYPE = "application/x-my-mime";
public static final DataFormat FORMAT = new DataFormat(MY_MIME_TYPE);
public static final DataFlavor FLAVOR = new DataFlavor(MY_MIME_TYPE, "My Mime Type");
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
// put a ByteBuffer to transfer the content unaffected
Collections.singletonMap(FORMAT, StandardCharsets.UTF_8.encode("Test")));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
byte[] textBytes = new byte[in.available()];
in.read(textBytes);
String transferred = new String(textBytes, StandardCharsets.UTF_8);
System.out.println("transferred text: " + transferred);
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
public static void main(String[] args) {
new MyApp().run();
}
private void run() {
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(1, 2));
frame.add(buildSwing());
SwingUtilities.invokeLater(() -> {
frame.add(buildFX());
});
frame.setSize(300, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private JFXPanel buildFX() {
BorderPane parent = new BorderPane();
parent.setOnDragDetected(event -> {
startDrag(parent);
event.consume();
});
JFXPanel panel = new JFXPanel();
panel.setScene(new Scene(parent));
return panel;
}
private JPanel buildSwing() {
JPanel panel = new JPanel();
panel.setBackground(Color.ORANGE);
panel.setTransferHandler(new TransferHandler() {
private static final long serialVersionUID = 1L;
@Override
public boolean canImport(TransferSupport support) {
return support.isDataFlavorSupported(FLAVOR);
}
@Override
public boolean importData(TransferSupport support) {
if (canImport(support)) {
return processData(support);
}
return false;
}
});
return panel;
}
}
输出：transferred text: Test
这里最重要的部分是：
...
private void startDrag(Node node) {
node.startDragAndDrop(TransferMode.COPY).setContent(
// put a ByteBuffer to transfer the content unaffected
Collections.singletonMap(FORMAT, StandardCharsets.UTF_8.encode("Test")));
}
private boolean processData(TransferSupport support) {
try (InputStream in = (InputStream) support.getTransferable().getTransferData(FLAVOR)) {
byte[] textBytes = new byte[in.available()];
in.read(textBytes);
String transferred = new String(textBytes, StandardCharsets.UTF_8);
System.out.println("transferred text: " + transferred);
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
...
再次说明，这里的流、错误等处理很简单。
需要注意的一件事是，还有一个预定义的 "application/x-java-serialized-object" (DataFlavor.javaSerializedObjectMimeType) 用于更通用和更容易的反序列化。但长期自定义 MIME 似乎更灵活，整体处理起来更直接。