(转)SWT的CheckBoxTreeViewer的相关用法

最近在项目中需要用到遍历某个目录下所有文件,并按照树形结构展示,同时还需要提供对树形菜单的选择展开等操作。在eclipse中提供了CheckboxTreeViewer组件来满足所需要的功能
下面是需要实现的功能:
按照树形菜单列出指定目录下文件列表
对菜单操作的相应处理,如选中父级菜单子集选中等
选中的菜单内容保存,并再次打开中默认选中
 
1、使用TitleAreaDialog创建 
TitleAreaDialog是Eclipse的Jface组件中的一个对话框,提供了显示的标题、提示信息和图标以及和内容区域,以及两个默认的按钮。我们在eclipse中常见的New Java Class Wizard就是一个典型的界面。
在自定义的界面中需要继承TitleAreaDialog
Java代码  
public class FrameworkFilterDialog extends TitleAreaDialog  
 绘制具体界面内容:实现createDialogArea
Java代码  
@Override  
    protected Control createDialogArea(Composite parent) {  
        Composite area = (Composite) super.createDialogArea(parent);  
        Composite container = new Composite(area, SWT.NONE);  
        container.setLayoutData(new GridData(GridData.FILL_BOTH));  
        //设置消息标题、消息信息  
        setTitle("Configuration ...........");  
        setMessage("配置该工程下的文件..........");  
  
        //主体内容部分,这里做一些必要描述  
        Label lblNewLabel = new Label(container, SWT.NONE);  
        lblNewLabel.setBounds(0, 0, 658, 39);  
        lblNewLabel.setText("工程名:  " + project.getName() + "
请选择需要的文件.........................");  
  
        IPath path = project.getRawLocation();  
  
        //这里绑定CheckboxTreeViewer 的相关属性和事件监听  
        CheckboxTreeViewer checkboxTreeViewer = new CheckboxTreeViewer(container, SWT.BORDER);  
        checkboxTreeViewer.setContentProvider(new FrameworkConfigContentProvider());  
        checkboxTreeViewer.setLabelProvider(new FrameworkConfigLabelProvider());  
        checkboxTreeViewer.addCheckStateListener(new FrameworkCheckedListener(path.toOSString()));  
        checkboxTreeViewer.setInput(ProjectFileDirUtil.listProjectFileDirec(path.toString()));  
  
        Tree tree = checkboxTreeViewer.getTree();  
        tree.setBounds(0, 45, 658, 229);  
        List<String> checkedList = FrameFilterManager.getManager().getFrameworkFilterFiles(project.getName());  
  
        //bind tree expand event: initialize tree checked  
        tree.addListener(SWT.Expand, new FrameworkExpandListener(checkedList));  
  
        //set initialize checked: first level tree checked  
        if (!LogicUtil.isEmpty(checkedList)) {  
            File[] file = ProjectFileDirUtil.changePathToFiles(checkedList);  
            checkboxTreeViewer.setCheckedElements(file);  
        }  
  
        return area;  
    }  
 运行的效果如下:

 
2、这里对CheckboxTreeViewer的几个属性设置做进一步说明
Java代码  
checkboxTreeViewer.setContentProvider(new FrameworkConfigContentProvider());  
checkboxTreeViewer.setLabelProvider(new FrameworkConfigLabelProvider());  
 根据方法名很容易知道,是对该树形结构提供数据和展现哪些数据。需要分别实现接口ITreeContentProvider:提供了获取下级元素和获取元素的方法。这里是一个简单的例子:
Java代码  
public class FrameworkConfigContentProvider implements ITreeContentProvider {  
  
    @Override  
    public void dispose() {  
  
    }  
  
    @Override  
    public void inputChanged(Viewer arg0, Object arg1, Object arg2) {  
  
    }  
  
    @Override  
    public Object[] getChildren(Object parentElement) {  
        if (parentElement instanceof File) {  
            File file = (File) parentElement;  
            File[] list = file.listFiles(new ProjectDirFileFilter());  
            if (list == null || list.length <= 0) {  
                return new Object[0];  
            }  
            return list;  
        }  
        return new Object[0];  
    }  
  
    @Override  
    public Object[] getElements(Object inputElement) {  
        if (inputElement instanceof File[]) {  
            File[] fileList = (File[]) inputElement;  
            if (fileList == null || fileList.length <= 0) {  
                return new Object[0];  
            }  
            return fileList;  
        }  
        return new Object[0];  
    }  
  
    @Override  
    public Object getParent(Object arg0) {  
        return null;  
    }  
  
    @Override  
    public boolean hasChildren(Object inputElement) {  
        if (inputElement instanceof File) {  
            File file = (File) inputElement;  
            File[] list = file.listFiles(new ProjectDirFileFilter());  
            if (list == null || list.length <= 0) {  
                return false;  
            }  
            return true;  
        }  
        return false;  
    }  
}  
 
同样对LabelProvider主要用于绘制菜单是显示的内容,如图标、标题等
Java代码  
public class FrameworkConfigLabelProvider extends LabelProvider {  
  
    private static final String PACKAGE           = "src";  
    private static final String JAVA_FILE         = ".java";  
    private static final String XML_FILE          = ".xml";  
    private static final String PROP_FILE         = ".properties";  
  
    private Image               javaFile          = new Image(Display.getCurrent(), getClass().getResourceAsStream(  
                                                          CommonConstants.ICON_JAVA_OBJ));  
  
    private Image               file              = new Image(Display.getCurrent(), getClass().getResourceAsStream(  
                                                          CommonConstants.ICON_FILE_OBJ));  
  
    private Image               xmlFile           = new Image(Display.getCurrent(), getClass().getResourceAsStream(  
                                                          CommonConstants.ICON_XML_OBJ));  
  
    private Image               folderFile        = new Image(Display.getCurrent(), getClass().getResourceAsStream(  
                                                          CommonConstants.ICON_FILEFOLDER_OBJ));  
  
    private Image               packageFolderFile = new Image(Display.getCurrent(), getClass().getResourceAsStream(  
                                                          CommonConstants.ICON_PACKAGE_FOLDER));  
  
    private Image               propFile          = new Image(Display.getCurrent(), getClass().getResourceAsStream(  
                                                          CommonConstants.ICON_PROP_OBJ));  
  
    @Override  
    public Image getImage(Object element) {  
  
        if (element instanceof File) {  
            File file = (File) element;  
            String fileName = file.getName();  
            //source folder  
            if (fileName.equals(PACKAGE)) {  
                return packageFolderFile;  
            }  
            //folder  
            if (file.isDirectory()) {  
                return folderFile;  
            }  
            //judge by suffix  
            if (fileName.indexOf(JAVA_FILE) > 0) {  
                return javaFile;  
            } else if (fileName.indexOf(XML_FILE) > 0) {  
                return xmlFile;  
            } else if (fileName.indexOf(PROP_FILE) > 0) {  
                return propFile;  
            }  
        }  
        return file;  
    }  
  
    @Override  
    public String getText(Object element) {  
        File file = (File) element;  
        return file.getName();  
    }  
  
    @Override  
    public void dispose() {  
        javaFile.dispose();  
        packageFolderFile.dispose();  
        folderFile.dispose();  
        xmlFile.dispose();  
        propFile.dispose();  
        file.dispose();  
        super.dispose();  
    }  
  
}  
 
3、设置选中事件
包括两种:选中上级目录时子集目录全部选中、如果下级目录不是全部选中上级菜单也不能选中等
在CheckboxTreeViewer中提供了addCheckStateListener对选择事件的监听,这里需要实现上面说的功能:
Java代码  
checkboxTreeViewer.addCheckStateListener(new FrameworkCheckedListener(path.toOSString()));  
FrameworkCheckedListener需要实现接口ICheckStateListener
Java代码  
@Override  
public void checkStateChanged(CheckStateChangedEvent event) {  
    if (event.getChecked()) {  
        CheckboxTreeViewer viewer = (CheckboxTreeViewer) event.getSource();  
        //选中:设置下级菜单选中  
        viewer.setSubtreeChecked(event.getElement(), true);  
        //选中:如果是子集菜单,且同级菜单全是选中的时候设置parent选中  
        //同样如果此时parent所在的同级菜单全选中做相应的迭代处理  
        //TODO:获取所有选中的项,比较绝对路径  
  
    } else {  
        CheckboxTreeViewer viewer = (CheckboxTreeViewer) event.getSource();  
        //不选中:下级目录菜单全不选中  
        File file = (File) event.getElement();  
        viewer.setSubtreeChecked(file, false);  
        //不选中:如果父级菜单是选中不能设置为选中  
        File parent = file.getParentFile();  
        //这里需要注意如果是顶级菜单不再迭代设置,否则将会空指针  
        if (parent.exists() && !parent.getAbsolutePath().equals(projectRoot)) {  
            setParentUnchecked(viewer, file.getParentFile());  
        }  
    }  
  
}  
 
4、菜单选中内容保存和初始化默认选中 
对选择菜单的保存,采用这种方式提供了相应的事件监听okPressed:
Java代码  
/** 
 * 设置OK点击事件后相应处理 
 */  
@Override  
protected void okPressed() {  
    Object[] dirFiles = checkboxTreeViewer.getCheckedElements();  
    List<String> dataList = new ArrayList<String>();  
    for (Object obj : dirFiles) {  
        if (obj instanceof File) {  
            File file = (File) obj;  
            dataList.add(file.getAbsolutePath());  
        }  
    }  
    //将选中的结果保存  
    FrameFilterManager.getManager().saveFrameworkFilterFiles(project.getName(), dataList);  
    super.okPressed();  
}  
 对初始化选中是让人很纠结的一件事,在CheckboxTreeViewer中提供了setCheckedElements(Objects[ ] args)但是在实践中发现只会对一级菜单的项进行匹配选中,对二级或更多就无能为力了,不知道是我操作不正确还是怎么回事。
Java代码  
//set initialize checked: first level tree checked  
if (!LogicUtil.isEmpty(checkedList)) {  
    File[] file = ProjectFileDirUtil.changePathToFiles(checkedList);  
    checkboxTreeViewer.setCheckedElements(file);  
}  
 这里设置的对象需要和setInput中的数据类型保持一致。但是这里是会选中,也仅限于一级菜单。为了达到目的,这里对CheckboxTreeViewer中的Tree添加expand事件来实现
Java代码  
Tree tree = checkboxTreeViewer.getTree();  
tree.setBounds(0, 45, 658, 229);  
List<String> checkedList = FrameFilterManager.getManager().getFrameworkFilterFiles(project.getName());  
  
//bind tree expand event: initialize tree checked  
tree.addListener(SWT.Expand, new FrameworkExpandListener(checkedList));  
 这里FrameworkExpandListener需要实现SWT中的Listener接口,并根据特别的情况来设置相应的选中
Java代码  
@Override  
public void handleEvent(Event event) {  
  
    if (LogicUtil.isEmpty(checkedList)) {  
        checkedList = new ArrayList<String>();  
    }  
  
    //当前点击item  
    TreeItem item = (TreeItem) event.item;  
    TreeItem[] items = item.getItems();  
  
    for (TreeItem treeItem : items) {  
        File file = (File) treeItem.getData();  
        if (checkedList.contains(file.getAbsolutePath())) {  
            treeItem.setChecked(true);  
        }  
    }  
}  
原文地址:https://www.cnblogs.com/wangjiyuan/p/zhuan1.html