最佳实践 - SWT 表、表查看器、编辑支持

回答这个问题就像回答你喜欢哪种冰淇淋口味:)

问与答

问题 1：这是向 GUI 类添加表的最佳做法吗？似乎 GUI 类需要编写大量代码。

如果代码小于它不是一个坏主意。但如果 -

1. 代码很大（对我来说，如果它超过100行）。
2. 整个系统将超过几千行代码。
3. 其他人将维护它
4. 如果我需要即插即用的性质，例如今天就足够了，但将来我可能会使用。TableGrid
5. 如果我正在执行一些自定义绘制（在Windows绘画事件上执行一些自定义绘制）或使用自定义控件，则

我通常更喜欢对查看器/控件进行子类化。通过这种方式，我可以保持裸露的消息泵送代码，GUI控件和我的数据模型之间的分离。

问题 2：是否应该将 createColumns（） 方法和 createTableViewerColumn（） 方法移动到类 B？

不，你不应该。与您的情况一样，B类是您的数据模型/供应商。JFace编程模型支持MVC架构，如果可能的话，应该遵循它。建议的解决方案是使用一个新类来扩展 TableViewer。

问题 3：我在表格中的最后一列将是一个下拉/组合框。因此，我将不得不使用EditingSupport扩展一个类。它应该是A类还是B类？

我建议你去一个新的类，并在扩展的TableViewer中使用它。一个好处是，如果您要将数据写回某个数据库，那么您的查看器类将保持与数据库/持久性层无关。

代码示例

下面是一个简单的示例应用程序。如您所见，我可以通过更改类将组合编辑器更改为文本编辑器。而且，代码看起来干净简洁。OptionEditingSupport

主类

package sample;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class SampleApp 
{
    public SampleApp(Shell shell)
    {
        AppPersonViewer personViewer = new AppPersonViewer(shell, SWT.BORDER|SWT.V_SCROLL|SWT.FULL_SELECTION);
        DataModel model = new DataModel(20);
        personViewer.setInput(model);
    }

    public static void main(String[] args) {
        Display display = new Display ();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        new SampleApp(shell);
        shell.open ();

        while (!shell.isDisposed ()) {
            if (!display.readAndDispatch ()) display.sleep ();
        }

        display.dispose ();
    }
}

package sample;

import org.eclipse.jface.viewers.ColumnLabelProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.TableViewerColumn;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Table;

public class AppPersonViewer extends TableViewer
{
    public AppPersonViewer(Composite parent, int style) 
    {
        super(parent, style);
        Table table = getTable();
        GridData gridData = new GridData(SWT.FILL, SWT.FILL, true, true);
        table.setLayoutData(gridData);
        createColumns();
        table.setHeaderVisible(true);
        table.setLinesVisible(true);
        setContentProvider(new AppContentProvider());
    }

    private void createColumns()
    {
        String[] titles = { "First Name", "Second Name", "Age", "Country", "Likes SO" };
        int[] bounds = { 150, 150, 100, 150, 100 };

        TableViewerColumn column = createTableViewerColumn(titles[0], bounds[0], 0);
        column.setLabelProvider(new ColumnLabelProvider(){
            public String getText(Object element) {
                if(element instanceof Person)
                    return ((Person)element).getFirst();
                return super.getText(element);
            }
        });

        column = createTableViewerColumn(titles[1], bounds[1], 1);
        column.setLabelProvider(new ColumnLabelProvider(){
            public String getText(Object element) {
                if(element instanceof Person)
                    return ((Person)element).getSecond();
                return super.getText(element);
            }
        });

        column = createTableViewerColumn(titles[2], bounds[2], 2);
        column.setLabelProvider(new ColumnLabelProvider(){
            public String getText(Object element) {
                if(element instanceof Person)
                    return ""+((Person)element).getAge();
                return super.getText(element);
            }
        });

        column = createTableViewerColumn(titles[3], bounds[3], 3);
        column.setLabelProvider(new ColumnLabelProvider(){
            public String getText(Object element) {
                if(element instanceof Person)
                    return ((Person)element).getCountry();
                return super.getText(element);
            }
        });

        column = createTableViewerColumn(titles[4], bounds[4], 4);
        column.setLabelProvider(new ColumnLabelProvider(){
            public String getText(Object element) {
                if(element instanceof Person)
                    return ((Person)element).getLikes();
                return super.getText(element);
            }
        });

        column.setEditingSupport(new OptionEditingSupport(this));
    }

    private TableViewerColumn createTableViewerColumn(String header, int width, int idx) 
    {
        TableViewerColumn column = new TableViewerColumn(this, SWT.LEFT, idx);
        column.getColumn().setText(header);
        column.getColumn().setWidth(width);
        column.getColumn().setResizable(true);
        column.getColumn().setMoveable(true);

        return column;
    }
}

package sample;

import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.Viewer;

public class AppContentProvider implements IStructuredContentProvider
{
    /* (non-Javadoc)
     * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
     */
    public Object[] getElements(Object inputElement) {
        if(inputElement instanceof DataModel)
            return ((DataModel)inputElement).getData().toArray();
        return null;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.viewers.IContentProvider#dispose()
     */
    public void dispose() {
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
     */
    public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
    }
}

package sample;

import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.ComboBoxCellEditor;
import org.eclipse.jface.viewers.EditingSupport;
import org.eclipse.jface.viewers.TableViewer;

public class OptionEditingSupport extends EditingSupport 
{
    private ComboBoxCellEditor cellEditor;

    public OptionEditingSupport(ColumnViewer viewer) {
        super(viewer);
        cellEditor = new ComboBoxCellEditor(((TableViewer)viewer).getTable(), new String[]{"Y", "N"});
    }
    protected CellEditor getCellEditor(Object element) {
        return cellEditor;
    }
    protected boolean canEdit(Object element) {
        return true;
    }
    protected Object getValue(Object element) {
        return 0;
    }
    protected void setValue(Object element, Object value) 
    {
        if((element instanceof Person) && (value instanceof Integer)) {
            Integer choice = (Integer)value;
            String option = (choice == 0? "Y":"N");
            ((Person)element).setLikes( option );
            getViewer().update(element, null);
        }
    }
}

package sample;

import java.util.ArrayList;
import java.util.List;

public class DataModel 
{
    private int samples;
    public DataModel(int samples) {
        this.samples = samples;
    }

    List<Person> getData()
    {
        List<Person> persons = new ArrayList<Person>();
        for(int i=0; i<samples; i++)
            persons.add(Person.createRandomPerson());
        return persons;
    }
}

package sample;

import java.util.Random;

public class Person 
{
    private static final String[]   FIRST = {"Favonius", "Tim", "Brad", "Scott", "Linda"};
    private static final String[]   SECOND = {"Cruise", "Temp", "Abbey", "Adam", "Albert", "Thomas"};
    private static final String[]   COUNTRY = {"India", "USA", "Russia", "UK", "France", "Germany"};
    private static final int[]      AGE = {22, 23, 24, 25, 26, 27, 28, 29, 30};

    private static Random random = new Random(System.currentTimeMillis());

    private String first;
    private String second;
    private String country;
    private String likes;

    private int age;

    public Person(String first, String second, String country, String likes, int age) 
    {
        super();
        this.first = first;
        this.second = second;
        this.country = country;
        this.likes = likes;
        this.age = age;
    }
    public String getFirst() {
        return first;
    }
    public String getSecond() {
        return second;
    }
    public String getCountry() {
        return country;
    }
    public String getLikes() {
        return likes;
    }
    public int getAge() {
        return age;
    }
    public void setLikes(String likes) {
        this.likes = likes;
    }
    public static Person createRandomPerson(){
        return new  Person(FIRST[random.nextInt(FIRST.length)], 
                SECOND[random.nextInt(SECOND.length)], COUNTRY[random.nextInt(COUNTRY.length)], 
                "Y", AGE[random.nextInt(AGE.length)]);
    }
}

使用 TableViewer 插入列名和表项的简单方法

学生表查看器

package rcp_demo.Views;

import org.eclipse.swt.widgets.Composite;
import org.eclipse.ui.part.ViewPart;
import org.eclipse.swt.SWT;
import org.eclipse.wb.swt.SWTResourceManager;
import org.eclipse.swt.widgets.Table;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.jface.viewers.TableViewerColumn;
import org.eclipse.swt.widgets.Text;
import rcp_demo.TableView.Student;
import org.eclipse.swt.widgets.TableItem;
import java.util.ArrayList;
import java.util.List;

public class TaskView extends ViewPart {
    private Table table;
    private Text txt_search;
    private TableViewer tableViewer;
    public TaskView() {
        setTitleImage(SWTResourceManager.getImage("D:\\Icon\\Tasksview.png"));
    }

    @Override
    public void createPartControl(Composite parent) {
        parent.setLayout(null);
        //Search Text
        txt_search = new Text(parent, SWT.BORDER);
        txt_search.setBounds(21, 10, 238, 19);
        //TableViewer
        tableViewer = new TableViewer(parent, SWT.BORDER | SWT.FULL_SELECTION);
        table = tableViewer.getTable();
        table.setBounds(21, 47, 290, 213);
        table.setHeaderVisible(true);
        table.setLinesVisible(true);

                //Table(Student): TableViewerColumn Names

                String[] Col_names={"Stud_id","Stud_Name","Stud_Gender"};
                for(int i=0;i<Col_names.length;i++)
                {
                    TableViewerColumn tableViewerColumn = new TableViewerColumn(tableViewer, SWT.NONE);
                    TableColumn tblclmnNewColumn = tableViewerColumn.getColumn();
                    tblclmnNewColumn.setWidth(100);
                    tblclmnNewColumn.setText(Col_names[i]);

                }
                //Table(Student) Item List
                List<Student> std=new ArrayList<Student>();
                std.add(new Student("110","AAA","Male"));
                std.add(new Student("111","FFF","Female"));
                std.add(new Student("112","MMM","Male"));

                for(Student s:std)
                {
                    TableItem std_item=new TableItem(table, SWT.NONE);
                    std_item.setText(0,s.getStd_id());
                    std_item.setText(1,s.getStd_nm());
                    std_item.setText(2,s.getStd_gender());
//                  System.out.println(s);  
                }

    }
      public TableViewer getViewer() {
          return tableViewer;
  }
    @Override
    public void setFocus() {
        tableViewer.getControl().setFocus();

    }
}

班级 ： 学生

package rcp_demo.TableView;

public class Student {

    private String std_id;
    private String std_nm;
    private String std_gender;

    public Student() {
        // TODO Auto-generated constructor stub
    }
    public Student(String sid,String snm,String sgender) {
        std_id=sid;
        std_nm=snm;
        std_gender=sgender;
    }

    public String getStd_id() {
        return std_id;
    }
    public void setStd_id(String std_id) {
        this.std_id = std_id;
    }
    public String getStd_nm() {
        return std_nm;
    }
    public void setStd_nm(String std_nm) {
        this.std_nm = std_nm;
    }
    public String getStd_gender() {
        return std_gender;
    }
    public void setStd_gender(String std_gender) {
        this.std_gender = std_gender;
    }

}

我了解了 SWT 表、表查看器的最佳实践

谢谢。。