How to use GWT 2.1 Data Presentation Widgets
Asked Answered
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45

At the 2010 Google IO it was announced that GWT 2.1 would include new Data Presentation Widgets. 2.1M is available for download, and presumably the widgets are included, but no documentation has yet surfaced.

Is there a short tutorial or example for how to use them? I've seen a rumor that CellList and CellTable are the classes in question. The Javadoc for them is riddled with lots of TODOs, so quite a bit is still missing in terms of usage.

Intermarriage answered 23/5, 2010 at 12:59 Comment(3)
I see big points to be had for answering this :)Sawdust
Unfortunately no answers seem to be forthcoming. This seems to be a sad trend for Google IO- announce Cool New Tech, make fleeting references to it in various documentation (e.g. last year's "use MVP"), and then let months pass before fully releasing or explaining it. :-(Intermarriage
M2 was just released. added link to eclipse update site in answer.Sawdust
S
28

Google I/O 2010 - GWT's UI overhaul

javadocs package com.google.gwt.cell.client in 2.1

Eclipse update site for milestone 2

While the code is in bikeshed, add this line to your gwt.xml file:

<inherits name='com.google.gwt.requestfactory.RequestFactory'/>

The following examples follow:

  • CellList of TextCells with PageSizePager
  • CellList of TextCells with a SimplePager
  • CellList of TextCells with a SimplePager and PageSizePager(buggy) and
  • CellTable with String header and TextCell header

package dpw.client;

import java.util.ArrayList;

import com.google.gwt.cell.client.TextCell;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.cellview.client.CellList;
import com.google.gwt.user.cellview.client.CellTable;
import com.google.gwt.user.cellview.client.PageSizePager;
import com.google.gwt.user.cellview.client.SimplePager;
import com.google.gwt.user.cellview.client.TextColumn;
import com.google.gwt.user.cellview.client.Header;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.view.client.ListViewAdapter;

public class Index implements EntryPoint {

    public void onModuleLoad() {

        // create some data
        ArrayList<String> values = new ArrayList<String>();
        values.add("one");
        values.add("two");
        values.add("three");
        values.add("four");
        values.add("five");
        values.add("six");

        // create a ListViewAdapter
        ListViewAdapter<String> lva = new ListViewAdapter<String>();
        // give the ListViewAdapter our data
        lva.setList(values);

        {
            // CellList of TextCells with PageSizePager
            CellList<String> cl = new CellList<String>(new TextCell());
            // set the initial pagesize to 2
            cl.setPageSize(2);

            // add the CellLists to the adaptor
            lva.addView(cl);

            // create a PageSizePager, giving it a handle to the CellList
            PageSizePager<String> psp = new PageSizePager<String>(cl, 2);

            // add the CellList to the page
            RootPanel.get().add(cl);

            // add the PageSizePager to the page
            RootPanel.get().add(psp);
        }

        RootPanel.get().add(new HTML("<hr />"));

        {
            // CellList of TextCells with a SimplePager
            CellList<String> cl = new CellList<String>(new TextCell());
            // set the initial pageSize to 2
            cl.setPageSize(2);

            // add the CellLists to the adaptor
            lva.addView(cl);

            // create a pager, giving it a handle to the CellList
            SimplePager<String> pager = new SimplePager<String>(cl,
                    SimplePager.TextLocation.CENTER);

            // add the CellList to the page
            RootPanel.get().add(cl);

            // add the Pager to the page
            RootPanel.get().add(pager);
        }

        RootPanel.get().add(new HTML("<hr />"));

        {
            // CellList of TextCells with a SimplePager and PageSizePager
            CellList<String> cl = new CellList<String>(new TextCell());
            // set the initial pageSize to 2
            cl.setPageSize(2);

            // add the CellLists to the adaptor
            lva.addView(cl);

            // create a PageSizePager, giving it a handle to the CellList
            PageSizePager<String> psp = new PageSizePager<String>(cl, 1);

            // create a pager, giving it a handle to the CellList
            SimplePager<String> pager = new SimplePager<String>(cl,
                    SimplePager.TextLocation.CENTER);

            // add the CellList to the page
            RootPanel.get().add(cl);

            // add the Pager to the page
            RootPanel.get().add(pager);

            // add the PageSizePager to the page
            RootPanel.get().add(psp);
        }

        RootPanel.get().add(new HTML("<hr />"));

        {
            // CellTable
            CellTable<String> ct = new CellTable<String>();
            ct.setPageSize(2);
            lva.addView(ct);

            // add a column with a simple string header
        ct.addColumn(new TextColumn<String>() {

            @Override
            public String getValue(String object) {
                return object;
            }
        }, "String Header");

        //add a column with a TextCell header
        ct.addColumn(new TextColumn<String>() {

            @Override
            public String getValue(String object) {
                return "%" + object + "%";
            }
        }, new Header<String>(new TextCell()) {

            @Override
            public String getValue() {
                return "TextCell Header";
            }
        });

            // create a pager, giving it a handle to the CellTable
            SimplePager<String> pager = new SimplePager<String>(ct,
                    SimplePager.TextLocation.CENTER);

            // add the CellList to the page
            RootPanel.get().add(ct);

            // add the Pager to the page
            RootPanel.get().add(pager);
        }
    }
}
Sawdust answered 31/5, 2010 at 15:22 Comment(15)
There are 3 things in play: the View itself, 2 pagers, and the adapter. If you can get your head wrapped around that, things get easier.Sawdust
The View(CellList) only holds data its displaying, not the whole dataset, which is what tripped me up for a while.Sawdust
Actually, two pagers for one ListView doesn't work(not sure if its a bug or intentional). Either use a SimplePager OR a PageSizePager.Sawdust
Very nice, Antony. CellList seems to be for a single column, and CellTable is for multi-column. They both implement PagingListView. However I can't see how to feed multi-column data to CellTable.Intermarriage
I'm working on that now. It looks like they're both a single list, with CellTable's columns representing different attributes of your data. Not the behavior I expected.Sawdust
I can't figure out how to hook up two ListViews to the same dataset and Pager so they page in sync.Sawdust
Hmm, maybe the videos coming out tomorrow will have more clues: googlecode.blogspot.com/2010/05/…Intermarriage
youtube.com/…Sawdust
Thanks for the sample code. I've been trying to work out how to add a header to the CellTable table but I have to construct a Header Object that takes a cell and can't figure out for the life of me the way to set them up. An update to the sample with headers would be much appreciated.Azpurua
@Azpurua added headers to the CellTable exampleSawdust
Excellent, thanks! BTW: you're now missing import com.google.gwt.user.cellview.client.Header;Jamison
they moved out of bikeshed, so no additional inherits should be needed.Sawdust
Is there a way to add a click handler to the headers? I can handle selection of the rows but I don't see any way to handle the headers.Amorphous
@Amorphous that would be a perfect stand-alone question.Sawdust
@Sawdust I opened a question at #3262660 I'm playing with the code now and may have a way to do this. I'll update that record tomorrow if i figure it out.Amorphous
S
5

I have a working prototype of an editable CellTable. The prototype has a Table displaying String, Boolean, Date, Integer columns with editors for each. Editing each cell updates the corresponding model.

public class CellTableDemo implements EntryPoint
{
    public void onModuleLoad( )
    {
        CellTable<SomeDTO> cellTable = createTable( );

        addColumns( cellTable );

        ListViewAdapter<SomeDTO> listViewAdapter = new ListViewAdapter<SomeDTO>( );
        listViewAdapter.setList( getData( ) );
        listViewAdapter.addView( cellTable );

        RootPanel.get( ).add( new SimplePager<SomeDTO>( cellTable, SimplePager.TextLocation.CENTER ) );
        RootPanel.get( ).add( cellTable );
    }

    private CellTable<SomeDTO> createTable( )
    {
        CellTable<SomeDTO> cellTable = new CellTable<SomeDTO>( );
        cellTable.setSelectionEnabled( true );
        cellTable.setSelectionModel( new SingleSelectionModel<SomeDTO>( ) );
        cellTable.setPageSize( 5 );
        cellTable.setPageStart( 0 );
        return cellTable;
    }

    private void addColumns( CellTable<SomeDTO> cellTable )
    {
        Column<SomeDTO, String> colA = new Column<SomeDTO, String>( new TextInputCell( ) )
        {
            public String getValue( SomeDTO object )
            {
                return object.getA( );
            }
        };
        colA.setFieldUpdater( new FieldUpdater<SomeDTO, String>( ) // updates changes into the backing bean
                {
                    public void update( int index, SomeDTO object, String value )
                    {
                        object.setA( value );
                    }
                } );
        cellTable.addColumn( colA, "String Column A" );

        cellTable.addColumn( new Column<SomeDTO, Integer>( new CurrencyCell( ) )
        {
            public Integer getValue( SomeDTO object )
            {
                return object.getB( );
            }
        }, "Currency Column B" );

        Column<SomeDTO, Boolean> colC = new Column<SomeDTO, Boolean>( new CheckboxCell( ) )
        {
            public Boolean getValue( SomeDTO object )
            {
                return object.getC( );
            }
        };
        colC.setFieldUpdater( new FieldUpdater<SomeDTO, Boolean>( )
        {
            public void update( int index, SomeDTO object, Boolean value )
            {
                object.setC( value );
            }
        } );
        cellTable.addColumn( colC, "Boolean Column C" );

        Column<SomeDTO, Date> colD = new Column<SomeDTO, Date>( new DatePickerCell( ) )
        {
            public Date getValue( SomeDTO object )
            {
                return object.getD( );
            }
        };
        colD.setFieldUpdater( new FieldUpdater<SomeDTO, Date>( )
        {
            public void update( int index, SomeDTO object, Date value )
            {
                object.setD( value );
            }
        } );
        cellTable.addColumn( colD, "Date Column D" );

        cellTable.addColumn( new Column<SomeDTO, String>( new ActionCell<String>( "Click of summary of this row", new Delegate<String>( )
        {
            public void execute( String row )
            {
                Window.alert( row );
            }
        } ) )
        {
            public String getValue( SomeDTO row )
            {
                return row.getSummary( );
            }
        } );
    }

    private ArrayList<SomeDTO> getData( )
    {
        ArrayList<SomeDTO> tableData = new ArrayList<SomeDTO>( );
        tableData.add( new SomeDTO( "A", 10, true, new Date( ) ) );
        tableData.add( new SomeDTO( "AA", 200, false, new Date( ) ) );
        tableData.add( new SomeDTO( "AAA", 3000, true, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAA", 40, false, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAA", 500, true, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAAA", 6000, false, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAAAA", 70, true, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAAAAA", 800, false, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAAAAAA", 9000, true, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAAAAAAA", 10, false, new Date( ) ) );
        tableData.add( new SomeDTO( "AAAAAAAAAAA", 11, true, new Date( ) ) );
        return tableData;
    }

    public class SomeDTO
    {
        private String a;
        private Integer b;
        private Boolean c;
        private Date d;

        public SomeDTO( String a, Integer b, Boolean c, Date d )
        {
            this.a = a;
            this.b = b;
            this.c = c;
            this.d = d;
        }

        public String getA( )
        {
            return a;
        }

        public void setA( String a )
        {
            this.a = a;
        }

        public Integer getB( )
        {
            return b;
        }

        public void setB( Integer b )
        {
            this.b = b;
        }

        public Boolean getC( )
        {
            return c;
        }

        public void setC( Boolean c )
        {
            this.c = c;
        }

        public Date getD( )
        {
            return d;
        }

        public void setD( Date d )
        {
            this.d = d;
        }

        public String getSummary( )
        {
            return getA( ) + "  " + getB( ) + "  " + getC( ) + "  " + getD( );
        }

    }

}
Symbolize answered 23/5, 2010 at 12:59 Comment(3)
I am having trouble getting the DatePickerCell to update the model value. Any pointers to where I am going wrong?Symbolize
nice answer. Did you try debugging? It could be that you're not doing anything wrong, but the GWT code is not ... ready? This is still M1 (unfortunatly).Jamison
@Nicolas I haven't debugged deeply yet. Some broken custom widgets from my existing GWT 2.0.3 project were a far bigger concern to me than chasing a bug in a feature which I have not yet used :PSymbolize
K
4

To show multiple column in table you need to put array in list. The reference code to achieve this is:

package com.test.client;

import java.util.ArrayList;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.cellview.client.CellTable;
import com.google.gwt.user.cellview.client.SimplePager;
import com.google.gwt.user.cellview.client.TextColumn;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.view.client.ListViewAdapter;
import com.google.gwt.view.client.SingleSelectionModel;

public class Index implements EntryPoint {

    public void onModuleLoad() {

        // create some data
        ArrayList<String[]> values = new ArrayList<String[]>();
        values.add(new String[] { "1", "a" });
        values.add(new String[] { "2", "b" });
        values.add(new String[] { "3", "c" });
        values.add(new String[] { "4", "d" });
        values.add(new String[] { "5", "e" });
        values.add(new String[] { "6", "f" });
        values.add(new String[] { "7", "g" });
        values.add(new String[] { "8", "h" });
        values.add(new String[] { "9", "i" });
        values.add(new String[] { "10", "j" });


        // create a ListViewAdapter
        ListViewAdapter<String[]> lva = new ListViewAdapter<String[]>();
        // give the ListViewAdapter our data
        lva.setList(values);

        RootPanel.get().add(new HTML("<hr />"));

        {
            // CellTable
            CellTable<String[]> ct = new CellTable<String[]>();
            ct.setSelectionEnabled(true);
            ct.setSelectionModel(new SingleSelectionModel());
            ct.setPageSize(2);
            lva.addView(ct);
            ct.addColumn(new TextColumn<String[]>() {

                @Override
                public String getValue(String[] object) {
                    return object[0];
                }
            }, "First");

            ct.addColumn(new TextColumn<String[]>() {

                @Override
                public String getValue(String[] object) {
                    return "%" + object[1] + "%";
                }
            }, "Second");

            // create a pager, giving it a handle to the CellTable
            SimplePager<String[]> pager = new SimplePager<String[]>(ct, SimplePager.TextLocation.CENTER);

            // add the Pager to the page
            RootPanel.get().add(pager);

            // add the CellList to the page
            RootPanel.get().add(ct);
        }
    }
}
Kansas answered 1/6, 2010 at 9:4 Comment(0)
C
3

The following code is what I'm woking on, hope it'll be helpful:

protected void init() {
    VerticalPanel container = new VerticalPanel();
    initWidget(container);

    int pageSize = 10;
    CellTable<User> cellTable = new CellTable<User>(pageSize);
    setColumns(cellTable);
    setSelectionModel(cellTable);

    setDataSize(cellTable);
    int pageStart = 0;
    loadData(pageStart, pageSize, cellTable);

    SimplePager<User> pager = createPager(cellTable);

    container.add(cellTable);
    container.add(pager);
}

private SimplePager<User> createPager(final CellTable<User> cellTable) {
    SimplePager<User> pager = new SimplePager<User>(cellTable,
            SimplePager.TextLocation.CENTER) {
        public void onRangeOrSizeChanged(PagingListView<User> listView) {
            loadData(listView.getPageStart(), listView.getPageSize(),
                    listView);
            super.onRangeOrSizeChanged(listView);
        }
    };
    return pager;
}

private void setColumns(CellTable<User> cellTable) {
    cellTable.addColumn(new TextColumn<User>() {
        @Override
        public String getValue(User user) {
            return user.getName();
        }
    }, new TextHeader("Name"));

    cellTable.addColumn(new TextColumn<User>() {
        @Override
        public String getValue(User user) {
            return user.getLocation();
        }
    }, new TextHeader("Location"));
}

private void setSelectionModel(CellTable<User> cellTable) {
    final SingleSelectionModel<User> selectionModel = new SingleSelectionModel<User>();
    SelectionChangeHandler selectionHandler = new SelectionChangeHandler() {
        @Override
        public void onSelectionChange(SelectionChangeEvent event) {
            User user = selectionModel.getSelectedObject();
            Window.alert(user.getId() + ": " + user.getName());
        }
    };
    selectionModel.addSelectionChangeHandler(selectionHandler);
    cellTable.setSelectionEnabled(true);
    cellTable.setSelectionModel(selectionModel);
}

private void setDataSize(final PagingListView<User> cellTable) {
    employeeRequest.countUsers(new AsyncCallback<Integer>() {
        public void onFailure(Throwable caught) {
            Window.alert("Request failure: " + caught.getMessage());
        }

        public void onSuccess(Integer result) {
            cellTable.setDataSize(result, true);
        }
    });
}

private void loadData(int start, int size,
        final PagingListView<User> cellTable) {
    employeeRequest.getUsers(start, size,
            new AsyncCallback<PagingData<User>>() {
                public void onFailure(Throwable caught) {
                    Window.alert("Request failure: " + caught.getMessage());
                }

                public void onSuccess(PagingData<User> result) {
                    cellTable.setData(result.getStart(),
                            result.getLength(), result.getValues());
                }
            });
}

public class PagingData<T> implements IsSerializable {

private int start;

private int length;

private List<T> values;

public PagingData() {
}

public PagingData(int start, int length, List<T> values) {
    super();
    this.start = start;
    this.length = length;
    this.values = values;
}

public int getStart() {
    return start;
}

public void setStart(int start) {
    this.start = start;
}

public int getLength() {
    return length;
}

public void setLength(int length) {
    this.length = length;
}

public List<T> getValues() {
    return values;
}

public void setValues(List<T> values) {
    this.values = values;
}
}
Cupped answered 3/6, 2010 at 3:37 Comment(1)
hey andrew, I have been looking every where for an example like yours, however I don't know enough about what I am doing to get your example to work partly because I am using GWT 2.3 and mostly I am having trouble wrapping my head around celltables/paging/data providers. Do you have a full or updated version of this code. Thanks in advanceUndulation
J
3

Great answer from antony.trupe above.

If you want to have an editable cell, you could add this piece of code to his class, and instanciate such a column instead of the regular TextColumn.

I'm sure you understand the FieldUpdater part. It's basically designed to update the underlying model -- which is not possible in the case of String.

I'll try to post a more complete example later on.

static class EditableColumn<T> extends Column<T, String> {

    public EditableColumn()
    {
        super(new EditTextCell());

        // workaround a NPE in EditTextCell.java:75 
        super.setFieldUpdater( new FieldUpdater<T, String>(){
            @Override
            public void update( int index, T object, String value ) {
                // I think object should be updated with the new value, which cannot be done
                // in a generic way (and cannot be done if T is String (immutable)).
                // Doing nothing here will at least update the view (probably not the model)
                System.out.println(index+":"+object+":"+value);
            }
        });
    }

    @Override
    public String getValue(T object) {
        return "%" + object + "%";
    }
}
Jamison answered 10/6, 2010 at 12:16 Comment(1)
Hmmm... it's a bit tricky to post something useful given the current state... EditTextCell.commit calling cancel? "This is a squirrelly" (Column.java:143)Jamison
H
0

You may want to take a look at Spring Roo project. Spring Roo in general is used to scaffold Java applications. In the newest version 1.1 it can also scaffold GWT applications (using many GWT 2.1 features).

It can generate a lot of GWT 2.1 code for you and then you can see how everything works together. The information about Spring Roo is also given in GWT 2.1 release notes and the tool was presented in Google I/O Keynote (it is really interesting, the video can be found here).

Edit:

There is even a complete example of GWT 2.1 application (Expenses application) in Spring Roo. To generate this application you only need to install Roo 1.1 and then execute this in roo console:

script -f samples/expenses.roo
Huston answered 3/6, 2010 at 16:59 Comment(0)

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