如何在 SWT 中将控件从一个 TabItem 拖放到另一个 TabItem答案

【问题标题】：How to drag and drop a control from one TabItem to another TabItem in SWT如何在 SWT 中将控件从一个 TabItem 拖放到另一个 TabItem
【发布时间】：2014-05-05 06:03:41
【问题描述】：

我正在尝试在 SWT 中使用 DND（拖放）。 TreeView 似乎工作正常。我想将一个控件（截至目前的标签）从一个 TabItem 拖放到 TabFolder 中的另一个 TabItem。

这里我创建了一个 TabFolder 和两个 TabItems 并使用 setControl 来定义每个 TabItem 里面的内容

class DNDTab {

    TabFolder tabFolder = new TabFolder(composite, SWT.NONE);
    tabFolder.setLayoutData(new GridData(SWT.FILL,GridData.FILL, true, true));

    tabItem = new TabItem(tabFolder, SWT.NONE);
    tabItem.setText("Favorite");
    tabItem.setControl(new CompositeFav(tabFolder));

    tabItem = new TabItem(tabFolder, SWT.NONE);
    tabItem.setText("Verified");
    tabItem.setControl(new CompositeVerified(tabFolder));
}

这里定义了经过验证的 TabItem

class CompositeVerified extends Composite {
    CompositeVerified(Composite parent) {
        super(parent, SWT.NONE);
        GridLayout layout = new GridLayout(1, false);
        setLayout(layout);

        String[] testList = {"My TestCase 1", "My TestCase 2",
                "My TestCase 3", "My     TestCase 4", "My TestCase 5"};

        for (int i = 0; i < 5; i++) {
            final Label dragLabel = new Label(this, SWT.NONE);
            dragLabel.setText(testList[i]);
            creatingDragSource(dragLabel);

            /*** createDragSource is my defined function where each label within the TabItem 
             * is made as a drag source using "DragSource source = new DragSource(dragLabel, operations);" 
             ***/
        }

    }
}

这里将Favorite TabItem作为放置目标

class CompositeFav extends Composite {
    CompositeFav(final Composite parent) {
        super(parent, SWT.NONE);

        DropTarget target = new DropTarget(parent, operations);
        target.setTransfer(types);

        target.addDropListener(new DropTargetListener() {
            /*** The part of the code where dragEnter, dragOver, drop events are added***/
        }
    }
}

拖动源创建良好，并且拖动似乎工作。但是当我将它放到 Fav TabItem 中时，它并没有被添加到那里。

【问题讨论】：

标签： java drag-and-drop swt

【解决方案1】：

tabFolder 首先捕获 dropTargetEvent... 丑陋的黑客：

为 tabFolder 创建 dropTarget
将 dropTargetEvent 转发到目标组合

像这样：

DropTarget target = new DropTarget(tabFolder, DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_DEFAULT);
        target.setTransfer(transfers);
        target.addDropListener(new DropTargetAdapter() {
            public void dragOver(DropTargetEvent event) {}

            public void dragEnter(DropTargetEvent event){}

            public void dragLeave(DropTargetEvent event){}

            public void drop(DropTargetEvent event) {
                DropTarget target = targetComposite.getData(DND.DROP_TARGET_KEY);
                target.getDropListeners()[0].drop(event);
            }
        });

【讨论】：