Package com.google.gwt.view.client

Class ListDataProvider<T>

java.lang.Object
com.google.gwt.view.client.AbstractDataProvider<T>
com.google.gwt.view.client.ListDataProvider<T>
Type Parameters:
T - the data type of the list
All Implemented Interfaces:
ProvidesKey<T>
public class ListDataProvider<T> extends AbstractDataProvider<T>
A concrete subclass of AbstractDataProvider that is backed by an in-memory list.

Modifications (inserts, removes, sets, etc.) to the list returned by getList() will be reflected in the model. However, mutations to the items contained within the list will NOT be reflected in the model. You must call List.set(int, Object) to update the item within the list and push the change to the display, or call refresh() to push all rows to the displays. List.set(int, Object) performs better because it allows the data provider to push only those rows which have changed, and usually allows the display to re-render only a subset of the rows.

Example

public class ListDataProviderExample implements EntryPoint {

  public void onModuleLoad() {
    // Create a CellList.
    CellList<String> cellList = new CellList<String>(new TextCell());

    // Create a list data provider.
    final ListDataProvider<String> dataProvider = new ListDataProvider<String>();

    // Add the cellList to the dataProvider.
    dataProvider.addDataDisplay(cellList);

    // Create a form to add values to the data provider.
    final TextBox valueBox = new TextBox();
    valueBox.setText("Enter new value");
    Button addButton = new Button("Add value", new ClickHandler() {
      public void onClick(ClickEvent event) {
        // Get the value from the text box.
        String newValue = valueBox.getText();

        // Get the underlying list from data dataProvider.
        List<String> list = dataProvider.getList();

        // Add the value to the list. The dataProvider will update the cellList.
        list.add(newValue);
      }
    });

    // Add the widgets to the root panel.
    VerticalPanel vPanel = new VerticalPanel();
    vPanel.add(valueBox);
    vPanel.add(addButton);
    vPanel.add(cellList);
    RootPanel.get().add(vPanel);
  }
}