jface databinding:使用CheckboxTableViewer实现表中(Set)对象与CheckTable中选中条目数据绑定

刺骨的言语ヽ痛彻心扉 2022-07-13 08:50 174阅读 0赞

上一篇博文[《jface databinding:可多选的widget List组件selection项目与java.util.List对象的双向数据绑定》][jface databinding_widget List_selection_java.util.List]讲述了如何实现List组件的多选项与List数据绑定的问题。  
实际使用中觉得用List组件来给用户做多选，用户体验不太好，比如用户可能不知道按下shift或ctrl键才能多选。经过比对，还是觉得用checkTable来实现比较好，  
如下图，左上是一个Table组件(CHECK)，勾选不同的名字，希望数据对象(ObservableSet)的内容也同步改变，显示在下面的Label组件中。按右侧的”添加”,”删除”,”清除”按钮改变ObservableSet的内容时，Table也同步改变。  
![这里写图片描述][SouthEast]  
要实现这个需求，用jface提供的JFace Viewers实现数据绑定非常方便，JFace Viewers为Table,Tree等复杂组件提供了一个方便的开发框架，如下图对于每一种复杂组件都有对应的Viewer类，实现本文需求所需要的京是红框标的CheckboxTableViewer。  
![这里写图片描述][SouthEast 1]  
以下是实现的核心代码：

WritableSet<String> observableSet=new WritableSet<String>();
            // 创建checkboxTableViewer对象
            checkboxTableViewer = CheckboxTableViewer.newCheckList(container, SWT.BORDER | SWT.FULL_SELECTION | SWT.MULTI);
            Table table = checkboxTableViewer.getTable();
            // 设置初始的表内容
            WritableSet<String> input=new WritableSet<String>();
            input.addAll(Arrays.asList("tom","jerry","donald","snow white"));
            // 设置ContentProvider,ContentProvider会将input内容显示在Table中
            // 如果不执行此步，则下一步会抛出异常
            checkboxTableViewer.setContentProvider(new ObservableSetContentProvider());
            // 将input设置为checkboxTableViewer的输入，input的变化会同步到Table中
            checkboxTableViewer.setInput(input);
            // 创建数据绑定上下文
            DataBindingContext bindingContext = new DataBindingContext();
            // 调用ViewerProperties.checkedElements方法对checkboxTableViewer创建已选中项目观察对象
            IViewerObservableSet observeCheckedSetCheckboxTableViewer = ViewerProperties.checkedElements(String.class).observe(checkboxTableViewer);
            // 将CheckTable与数据对象observableSet绑定
            bindingContext.bindSet(observeCheckedSetCheckboxTableViewer, observableSet, null, null);
            // 将observableSet内容绑定到Label组件，当observableSet内容变化时，lblSelected显示会自动更新
            ISideEffect.create(
                    observableSet::size, (s)->{
                        lblSelected.setText(String.join(",", observableSet));
                });

完整的测试代码:  
TestTableSelected .java

package testwb;
    
    import org.eclipse.core.databinding.observable.Realm;
    import org.eclipse.core.databinding.observable.set.WritableSet;
    import org.eclipse.core.databinding.observable.sideeffect.ISideEffect;
    import org.eclipse.jface.databinding.swt.DisplayRealm;
    import org.eclipse.jface.dialogs.Dialog;
    import org.eclipse.jface.dialogs.IDialogConstants;
    import org.eclipse.swt.graphics.Point;
    import org.eclipse.swt.widgets.Composite;
    import org.eclipse.swt.widgets.Control;
    import org.eclipse.swt.widgets.Display;
    import org.eclipse.swt.widgets.Shell;
    import org.eclipse.swt.widgets.Table;
    import org.eclipse.swt.SWT;
    import org.eclipse.jface.viewers.CheckboxTableViewer;
    
    import java.util.Arrays;
    
    import org.eclipse.core.databinding.DataBindingContext;
    import org.eclipse.jface.databinding.viewers.IViewerObservableSet;
    import org.eclipse.jface.databinding.viewers.ObservableSetContentProvider;
    import org.eclipse.jface.databinding.viewers.ViewerProperties;
    import org.eclipse.swt.widgets.Label;
    import org.eclipse.swt.widgets.Button;
    import org.eclipse.swt.events.SelectionAdapter;
    import org.eclipse.swt.events.SelectionEvent;
    
    public class TestTableSelected extends Dialog {
        
        private DataBindingContext m_bindingContext;
        private WritableSet<String> observableSet=new WritableSet<String>();
        private CheckboxTableViewer checkboxTableViewer;
        private Label lblSelected;
        /**
         * Create the dialog.
         * @param parentShell
         */
        public TestTableSelected(Shell parentShell) {
            super(parentShell);
        }
    
        /**
         * Create contents of the dialog.
         * @param parent
         */
        @Override
        protected Control createDialogArea(Composite parent) {
            Composite container = (Composite) super.createDialogArea(parent);
            container.setLayout(null);
            observableSet.add("tom");
    
            checkboxTableViewer = CheckboxTableViewer.newCheckList(container, SWT.BORDER | SWT.FULL_SELECTION | SWT.MULTI);
            Table table = checkboxTableViewer.getTable();
            WritableSet<String> input=new WritableSet<String>();
            input.addAll(Arrays.asList("tom","jerry","donald","snow white"));
            checkboxTableViewer.setContentProvider(new ObservableSetContentProvider());
            checkboxTableViewer.setInput(input);
            table.setBounds(29, 42, 183, 85);
            table.pack();
    
            Button btnAdd = new Button(container, SWT.NONE);
            btnAdd.addSelectionListener(new SelectionAdapter() {
                @Override
                public void widgetSelected(SelectionEvent e) {
                    observableSet.add("jerry");
                }
            });
            btnAdd.setBounds(267, 42, 80, 27);
            btnAdd.setText("添加");
    
            Button btnDelete = new Button(container, SWT.NONE);
            btnDelete.addSelectionListener(new SelectionAdapter() {
                @Override
                public void widgetSelected(SelectionEvent e) {
                    observableSet.remove("tom");
                }
            });
            btnDelete.setBounds(267, 84, 80, 27);
            btnDelete.setText("删除");
    
            Button btnClear = new Button(container, SWT.NONE);
            btnClear.addSelectionListener(new SelectionAdapter() {
                @Override
                public void widgetSelected(SelectionEvent e) {
                    observableSet.clear();
                }
            });
            btnClear.setBounds(267, 126, 80, 27);
            btnClear.setText("清除");
            lblSelected = new Label(container, SWT.NONE);
            lblSelected.setBounds(29, 182, 449, 36);
    
            Label lblNewLabel_1 = new Label(container, SWT.NONE);
            lblNewLabel_1.setBounds(29, 163, 61, 17);
            lblNewLabel_1.setText("已选择：");
    
            return container;
        }
    
        /**
         * Create contents of the button bar.
         * @param parent
         */
        @Override
        protected void createButtonsForButtonBar(Composite parent) {
            createButton(parent, IDialogConstants.OK_ID, IDialogConstants.OK_LABEL, true);
            createButton(parent, IDialogConstants.CANCEL_ID, IDialogConstants.CANCEL_LABEL, false);
            m_bindingContext = initDataBindings();
        }
    
        /**
         * Return the initial size of the dialog.
         */
        @Override
        protected Point getInitialSize() {
            return new Point(494, 333);
        }
        public static void main(String[] args) {
            Display display = Display.getDefault();
            Realm.runWithDefault(DisplayRealm.getRealm(display), new Runnable() {
                public void run() {
                    try {
                        TestTableSelected testTable = new TestTableSelected(null);
                        testTable.open();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        }
        protected DataBindingContext initDataBindings() {
            DataBindingContext bindingContext = new DataBindingContext();
            //
            IViewerObservableSet observeCheckedSetCheckboxTableViewer = ViewerProperties.checkedElements(String.class).observe(checkboxTableViewer);
            bindingContext.bindSet(observeCheckedSetCheckboxTableViewer, observableSet, null, null);
            //
            ISideEffect.create(
                    observableSet::size, (s)->{
                        lblSelected.setText(String.join(",", observableSet));
                });
            return bindingContext;
        }
    }

参考资料:  
[《Data Binding for JFace Viewers》][Data Binding for JFace Viewers]

[jface databinding_widget List_selection_java.util.List]: http://blog.csdn.net/10km/article/details/53980235
[SouthEast]: /images/20220713/9854b9444d304cf196234ef369e86f37.png
[SouthEast 1]: /images/20220713/c51d4ee4e75e47c38b5f845a038fbde0.png
[Data Binding for JFace Viewers]: http://www.vogella.com/tutorials/EclipseDataBinding/article.html#data-binding-for-jface-viewers