SWT TreeViewer Drag n Drop：SWTException Widget 被释放

Question

我有一个 CTabFolder，其中包含几个一次性选项卡，每个选项卡都包含一个 TreeViewer。我希望每个查看器都有一个 DragSupport。所以我很自然地为此使用了TreeViewer#addDragSupport 方法。一切都按预期工作，除了当我关闭 shell 并且 SWT 尝试处理所有小部件时。

发生的异常是：

org.eclipse.swt.SWTException: Widget is disposed
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.widgets.Widget.error(Unknown Source)
at org.eclipse.swt.widgets.Widget.checkWidget(Unknown Source)
at org.eclipse.swt.widgets.Widget.removeListener(Unknown Source)
at org.eclipse.swt.dnd.DragSource.onDispose(Unknown Source)
at org.eclipse.swt.dnd.DragSource.access$1(Unknown Source)
at org.eclipse.swt.dnd.DragSource$2.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.swt.dnd.DragSource$1.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Canvas.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Decorations.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Shell.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.swt.widgets.Decorations.dispose(Unknown Source)
at org.eclipse.swt.widgets.Shell.dispose(Unknown Source)
at org.eclipse.jface.window.Window.close(Window.java:335)
at org.eclipse.jface.window.ApplicationWindow.close(ApplicationWindow.java:307)
at org.eclipse.jface.window.Window.handleShellCloseEvent(Window.java:741)
at org.eclipse.jface.window.Window$3.shellClosed(Window.java:687)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Decorations.closeWidget(Unknown Source)
at org.eclipse.swt.widgets.Decorations.WM_CLOSE(Unknown Source)
at org.eclipse.swt.widgets.Control.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Canvas.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Decorations.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
at org.eclipse.swt.internal.win32.OS.DefWindowProcW(Native Method)
at org.eclipse.swt.internal.win32.OS.DefWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.callWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Control.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Canvas.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Decorations.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
at org.eclipse.swt.internal.win32.OS.DefWindowProcW(Native Method)
at org.eclipse.swt.internal.win32.OS.DefWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.callWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Control.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Canvas.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Decorations.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW(Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(Unknown Source)
at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
at org.eclipse.jface.window.Window.runEventLoop(Window.java:825)
at org.eclipse.jface.window.Window.open(Window.java:801)

这似乎有点广泛。似乎 SWT 在处理后试图从树中删除 DragListener。我真的不明白这怎么可能。

我不认为我在实现 Source/Target 和 Transfer 类型时犯了错误，因为拖放就像一个魅力。

在将拖动支持添加到包含在一次性 Widget 中的 TreeViewer 时，是否需要考虑任何陷阱？

如果您需要代码示例，请告诉我。

Answer 1

这应该不是问题。您有 2 个选择：编写一段代码来给出该错误，或​​者只是在文件夹上添加一个 dispose 侦听器事件并删除那里的拖动支持。