为了让用户在WorkbenchPart（如IEditorPart）的Viewer（如TableViewer）里选择一个对象时，属性视图里能显示这个元素的属性，一般会将这个Viewer设置为该WorkbenchPart的site的selectionProvider：
editPart.getSite().setSelectionProvider(theViewer);
但如果是一个WorkbenchPart里有多个Viewer的情况呢？我们可以实现为当用户在任意一个Viewer里选择了一个对象后，属性视图里显示这个对象的属性。为此，根据黄老大的提示，需要写一个CompositeSelectionProvider，它实现ISelectionChangedListener以监听每个Viewer的选择事件，同时它要实现ISelectionProvider，因为我们要把它设置为该site的selectionProvider：
class
CompositeSelectionProvider
implements
ISelectionProvider, ISelectionChangedListener {
ISelection selection;
List listeners = new ArrayList();
public void addSelectionChangedListener(ISelectionChangedListener listener) {
listeners.add(listener);
}
public ISelection getSelection() {
return selection;
}
public void removeSelectionChangedListener(ISelectionChangedListener listener) {
listeners.remove(listener);
}
public void setSelection(ISelection selection) {
this .selection = selection;
final SelectionChangedEvent e = new SelectionChangedEvent( this , selection);
Object[] listenersArray = listeners.toArray();
for ( int i = 0 ; i < listenersArray.length; i ++ ) {
final ISelectionChangedListener l = (ISelectionChangedListener) listenersArray[i];
Platform.run( new SafeRunnable() {
public void run() {
l.selectionChanged(e);
}
});
}
}
/*****************************************************************
************** ISelectionChangedListener implementation **********
********************************************************** ******** /
public void selectionChanged(SelectionChangedEvent event) {
setSelection(event.getSelection());
}
}
ISelection selection;
List listeners = new ArrayList();
public void addSelectionChangedListener(ISelectionChangedListener listener) {
listeners.add(listener);
}
public ISelection getSelection() {
return selection;
}
public void removeSelectionChangedListener(ISelectionChangedListener listener) {
listeners.remove(listener);
}
public void setSelection(ISelection selection) {
this .selection = selection;
final SelectionChangedEvent e = new SelectionChangedEvent( this , selection);
Object[] listenersArray = listeners.toArray();
for ( int i = 0 ; i < listenersArray.length; i ++ ) {
final ISelectionChangedListener l = (ISelectionChangedListener) listenersArray[i];
Platform.run( new SafeRunnable() {
public void run() {
l.selectionChanged(e);
}
});
}
}
/*****************************************************************
************** ISelectionChangedListener implementation **********
********************************************************** ******** /
public void selectionChanged(SelectionChangedEvent event) {
setSelection(event.getSelection());
}
}
在WorkbenchPart#createPartControl()方法里让这个CompositeSelectionProvider监听每个viewer的选择事件，并把它设置为site的selectionProvider，代码如下：
//
The composite selectionProvider instance
CompositeSelectionProvider compositeSelectionProvider = new CompositeSelectionProvider();
public void createPartControl(Composite parent) {
//
viewer1.addSelectionChangedListener(compositeSelectionProvider);
viewer2.addSelectionChangedListener(compositeSelectionProvider);
//
getSite().setSelectionProvider(compositeSelectionProvider);
}
CompositeSelectionProvider compositeSelectionProvider = new CompositeSelectionProvider();
public void createPartControl(Composite parent) {
//
viewer1.addSelectionChangedListener(compositeSelectionProvider);
viewer2.addSelectionChangedListener(compositeSelectionProvider);
//
getSite().setSelectionProvider(compositeSelectionProvider);
}
注：在这篇教程里也有类似的解决方法，见“Multiple Selection Providers Within a Part”一节。
本文转自博客园八进制的博客，原文链接：让多个Viewer对应一个属性视图，如需转载请自行联系原博主。
