使用 GWT 2.4...
我正在构建一个复杂的复合双视图/编辑模式实现，该实现由 GWT 的 DataGrid 和 MultiSelectionModel 提供支持。我的目标是让用户能够单击他们想要发布更新的每一行中的复选框。
这是半功能界面的屏幕截图：
注意选定的（突出显示的）行。
现在的问题是，当我在任何单元格中输入内容时（例如，$/Mw 1 复合单元格标题下的第一行 $ 单元格），然后单击该行的复选框（或任何其他行的复选框）以选择或取消选择，第一次请求屏幕数据时，该值将重置为原始值。任何时候都不想要的行为！
让我们看一下我对网格的自定义实现。（请原谅长度）。
public abstract class ToggleableGrid<T extends Identifiable<?>> extends Composite {
private static final int CHKBOX_COLUMN_WIDTH = App.INSTANCE.checkboxColumnWidth();
private static final DisplayMode DEFAULT_MODE = DisplayMode.VIEW;
private ProvidesKey<T> keyProvider;
private DataGrid<T> grid;
private MultiSelectionModel<T> selectionModel;
private ListDataProvider<T> dataProvider;
private int tabIndex = 0;
public ToggleableGrid() {
final DataGridConfiguration config = new DefaultDataGridConfiguration();
initGrid(config);
}
public ToggleableGrid(DataGridConfiguration config) {
initGrid(config);
}
private void initGrid(DataGridConfiguration config) {
keyProvider = new ProvidesKey<T>() {
@Override
public Object getKey(T item) {
return item == null ? null : item.getId();
}
};
grid = new DataGrid<T>(config.getPageSize(), config.getResources(), keyProvider);
// Set the message to display when the table is empty.
grid.setEmptyTableWidget(new Label(UiMessages.INSTANCE.no_results()));
initWidget(grid);
setVisible(true);
}
public void setInput(List<T> content) {
setInput(content, DEFAULT_MODE);
}
public void setInput(List<T> content, DisplayMode mode) {
resetTableColumns();
if (isInEditMode(mode)) {
// Add a selection model so we can select cells
selectionModel = new MultiSelectionModel<T>(keyProvider);
grid.setSelectionModel(selectionModel, DefaultSelectionEventManager.<T> createCheckboxManager(0));
addRowSelector();
}
dataProvider = new ListDataProvider<T>(content);
final ListHandler<T> sortHandler = new ListHandler<T>(dataProvider.getList());
grid.addColumnSortHandler(sortHandler);
initializeStructure(constructMetadata(), sortHandler, mode);
dataProvider.addDataDisplay(grid);
}
// see https://stackoverflow.com/questions/3772480/remove-all-columns-from-a-celltable
// concrete classes are forced to maintain a handle on all columns added
private void resetTableColumns() {
for (final Column<T, ?> column: allColumns()) {
grid.removeColumn(column);
}
allColumns().clear();
}
protected boolean isInEditMode(DisplayMode currentDisplayMode) {
boolean result = false;
if (currentDisplayMode.equals(DisplayMode.EDIT)) {
result = true;
}
return result;
}
protected abstract Set<Column<T, ?>> allColumns();
protected abstract TableMetadata constructMetadata();
protected abstract void initializeStructure(TableMetadata metadata, ListHandler<T> sortHandler, DisplayMode mode);
protected void setColumnHorizontalAlignment(Column<T, ?> column, HorizontalAlignmentConstant alignment) {
column.setHorizontalAlignment(alignment);
}
// TODO figure out how to add a checkbox to column header that provides select/de-select all capability
// see https://stackoverflow.com/questions/6174689/gwt-celltable-programmatically-select-checkboxcell
protected void addRowSelector() {
final Column<T, Boolean> rowSelectColumn = new Column<T, Boolean>(new CheckboxCell(true, false)) {
@Override
public Boolean getValue(T value) {
Boolean result;
// check for null value and return null;
if(value == null || value.getId() == null) {
result = null;
} else { // get value from the selection model
result = selectionModel.isSelected(value);
}
return result;
}
};
addColumn(rowSelectColumn, UiMessages.INSTANCE.select());
setColumnWidth(rowSelectColumn, CHKBOX_COLUMN_WIDTH, Unit.PX);
setColumnHorizontalAlignment(rowSelectColumn, HasHorizontalAlignment.ALIGN_CENTER);
}
protected void setColumnWidth(Column<T, ?> column, int width, Unit unit) {
grid.setColumnWidth(column, width, unit);
}
protected void addColumn(Column<T, ?> column, String columnHeaderName) {
addColumn(column, columnHeaderName, HasHorizontalAlignment.ALIGN_RIGHT);
}
protected void addColumn(Column<T, ?> column, String columnHeaderName, HorizontalAlignmentConstant alignment) {
final SafeHtmlBuilder sb = new SafeHtmlBuilder();
final String divStart = "<div align=\""+ alignment.getTextAlignString() + "\" class=\"" +UiResources.INSTANCE.style().word_wrap() + "\">";
sb.appendHtmlConstant(divStart).appendEscaped(columnHeaderName).appendHtmlConstant("</div>");
final SafeHtml header = sb.toSafeHtml();
grid.addColumn(column, header);
allColumns().add(column);
}
protected CompositeCell<T> generateCompositeCell(final List<HasCell<T, ?>> hasCells) {
final CompositeCell<T> compositeCell = new CompositeCell<T>(hasCells) {
@Override
public void render(Context context, T value, SafeHtmlBuilder sb) {
sb.appendHtmlConstant("<table><tbody><tr>");
super.render(context, value, sb);
sb.appendHtmlConstant("</tr></tbody></table>");
}
@Override
protected Element getContainerElement(Element parent) {
// Return the first TR element in the table.
return parent.getFirstChildElement().getFirstChildElement().getFirstChildElement();
}
@Override
protected <X> void render(Context context, T value,
SafeHtmlBuilder sb, HasCell<T, X> hasCell) {
final Cell<X> cell = hasCell.getCell();
sb.appendHtmlConstant("<td>");
cell.render(context, hasCell.getValue(value), sb);
sb.appendHtmlConstant("</td>");
}
};
return compositeCell;
}
// FIXME not working quite the way we'd expect, index incremented within column for each row, not each row by column
protected int nextTabIndex() {
tabIndex++;
return tabIndex;
}
protected AbstractCellTable<T> getGrid() {
return grid;
}
/**
* Gets the selected (row(s) of) data from grid (used in edit mode)
* @return the selected data (as per selection model)
*/
public List<T> getSelectedData() {
final List<T> data = new ArrayList<T>();
data.addAll(selectionModel.getSelectedSet());
return data;
}
/**
* Gets all (row(s) of) data in grid (used in edit mode)
* @return all data as list
*/
public List<T> getAllData() {
return dataProvider.getList();
}
/**
* Clears the currently selected (row(s) of) data (used in edit mode)
*/
public void clearSelectedData() {
selectionModel.clear();
grid.redraw();
}
}
所以，盯着上面的有趣方法（我认为）是setInput，generateCompositeCell和addRowSelector。
我们用 List 数据初始化网格，并在 setInput 中设置显示模式。在这里也初始化了选择模型。它使用 GWT 的 DefaultSelectionEventManager createCheckboxManager()。
我一直在尝试理解事件模型，但它让我望而却步。我已经在线访问了以下资源，但在解决此问题的途径上还不够。
-- https://groups.google.com/forum/?fromgroups#!topic/google-web-toolkit/k5sfURxDaVg AbstractInputCell 的 getConsumedEventsImpl 增加了焦点、模糊和 keydown，所以这（我相信）不是我需要探索的轨道
-- GWT CellTable 以编程方式选择 CheckBoxCell 可以实例化 CheckBoxCell 的各种方法让我感到好奇，我尝试了许多构造函数参数排列，但我选择的一种（真，假）是（我相信）正确的一种
在这里和现在（在被谴责之前）同意我的实施中可能存在一些不必要的复杂性，但我仍在寻找指导。谢谢！
更新
如果它有帮助，这里是前面提到的 ToggleableGrid 的一个实现。如果有的话，它会为您提供有关每个 CompositeCell 内容的更多详细信息。有关 AbstractValidatableColumn 和 ValidatableInputCell 的详细信息，请参阅：寻找 GWT 验证示例...你在哪里？.
public class EnergyOfferGrid extends ToggleableGrid<EnergyOfferDTO> {
public EnergyOfferGrid() {
super();
}
public EnergyOfferGrid(DataGridConfiguration config) {
super(config);
}
private static final int MAX_NUMBER_OF_MW_PRICE_POINTS = App.INSTANCE.maxNoOfMwPricePoints();
private Set<Column<EnergyOfferDTO, ?>> columns = new HashSet<Column<EnergyOfferDTO, ?>>();
@Override
protected Set<Column<EnergyOfferDTO, ?>> allColumns() {
return columns;
}
@Override
protected TableMetadata constructMetadata() {
final TableMetadata metadata = new TableMetadata();
// TODO Consider a predefined set of ReferenceData to be held in a common package
// Use Slope
metadata.addColumnMetadata(UiMessages.INSTANCE.use_slope(), new String[] {UiMessages.INSTANCE.yes(), UiMessages.INSTANCE.no()}, new String[] {"true", "false"});
return metadata;
}
@Override
protected void initializeStructure(TableMetadata metadata, ListHandler<EnergyOfferDTO> sortHandler, DisplayMode currentDisplayMode) {
addHourColumn(sortHandler);
addUseSlopeColumn(metadata, sortHandler, currentDisplayMode);
for (int i = 0; i < MAX_NUMBER_OF_MW_PRICE_POINTS; i++) { // zero-based indexing
addPriceMwColumn(i, currentDisplayMode);
}
}
protected void addHourColumn(ListHandler<EnergyOfferDTO> sortHandler) {
final Column<EnergyOfferDTO, String> hourColumn = new Column<EnergyOfferDTO, String>(new TextCell()) {
@Override
public String getValue(EnergyOfferDTO energyOffer) {
String result = "";
if (energyOffer.getId() != null) {
final String isoDateTime = energyOffer.getId().getOperatingHour();
if (isoDateTime != null && !isoDateTime.isEmpty()) {
final Date dateTime = CSTimeUtil.isoToDate(isoDateTime);
if (dateTime != null) {
result = CSTimeUtil.dateToHour(dateTime);
}
}
}
return result;
}
};
hourColumn.setSortable(true);
sortHandler.setComparator(hourColumn, new Comparator<EnergyOfferDTO>() {
@Override
public int compare(EnergyOfferDTO eo1, EnergyOfferDTO eo2) {
final String date1 = eo1.getId() != null ? eo1.getId().getOperatingHour() : "";
final String date2 = eo2.getId() != null ? eo2.getId().getOperatingHour() : "";
return date1.compareTo(date2);
}
});
// We know that the data is sorted by hour by default.
getGrid(). getColumnSortList().push(hourColumn);
addColumn(hourColumn, UiMessages.INSTANCE.hour());
setColumnWidth(hourColumn, 45, Unit.PX);
setColumnHorizontalAlignment(hourColumn, HasHorizontalAlignment.ALIGN_RIGHT);
}
protected void addUseSlopeColumn(TableMetadata metadata, ListHandler<EnergyOfferDTO> sortHandler, DisplayMode currentDisplayMode) {
final ReferenceData refData = metadata.allColumnMetadata().get(UiMessages.INSTANCE.use_slope());
Column<EnergyOfferDTO, String> useSlopeColumn;
Cell<String> cell;
if (isInEditMode(currentDisplayMode)) {
cell = new ReferenceDataBackedSelectionCell(refData);
} else {
cell = new TextCell();
}
useSlopeColumn = new Column<EnergyOfferDTO, String>(cell) {
@Override
public String getValue(EnergyOfferDTO energyOffer) {
return refData.getDisplayValueForSubmitValue(Boolean.toString(energyOffer.isSlopeUsed()));
}
};
useSlopeColumn.setSortable(true);
sortHandler.setComparator(useSlopeColumn, new Comparator<EnergyOfferDTO>() {
@Override
public int compare(EnergyOfferDTO eo1, EnergyOfferDTO eo2) {
final String slopeUsed1 = String.valueOf(eo1.isSlopeUsed());
final String slopeUsed2 = String.valueOf(eo1.isSlopeUsed());
return slopeUsed1.compareTo(slopeUsed2);
}
});
addColumn(useSlopeColumn, UiMessages.INSTANCE.use_slope());
setColumnWidth(useSlopeColumn, 75, Unit.PX);
setColumnHorizontalAlignment(useSlopeColumn, HasHorizontalAlignment.ALIGN_RIGHT);
}
protected void addPriceMwColumn(final int colIndex, DisplayMode currentDisplayMode) {
// Construct a composite cell for energy offers that includes a pair of text inputs
final List<HasCell<EnergyOfferDTO, ?>> columns = new ArrayList<
HasCell<EnergyOfferDTO, ?>>();
// this DTO is passed along so that price and mw values for new entries are kept together
final OfferPriceMwPair newOfferPriceMwPair = new OfferPriceMwPair();
// Price
final Column<EnergyOfferDTO, String> priceColumn = generatePriceColumn(colIndex, newOfferPriceMwPair, currentDisplayMode);
columns.add(priceColumn);
// MW
final Column<EnergyOfferDTO, String> mwColumn = generateMwColumn(colIndex, newOfferPriceMwPair, currentDisplayMode);
columns.add(mwColumn);
// Composite
final CompositeCell<EnergyOfferDTO> priceMwColumnInnards = generateCompositeCell(columns);
final IdentityColumn<EnergyOfferDTO> priceMwColumn = new IdentityColumn<EnergyOfferDTO>(priceMwColumnInnards);
final StringBuilder colHeader = new StringBuilder();
colHeader.append(UiMessages.INSTANCE.price_mw_header()).append(" ").append(String.valueOf(colIndex + 1));
addColumn(priceMwColumn, colHeader.toString());
setColumnWidth(priceMwColumn, 7, Unit.EM);
setColumnHorizontalAlignment(priceMwColumn, HasHorizontalAlignment.ALIGN_RIGHT);
}
protected Column<EnergyOfferDTO, String> generatePriceColumn(final int colIndex, final OfferPriceMwPair newOfferPriceMwPair, DisplayMode currentDisplayMode) {
Column<EnergyOfferDTO, String> priceColumn;
if (isInEditMode(currentDisplayMode)) {
priceColumn = new BigDecimalValidatableColumn<EnergyOfferDTO, OfferPriceMwPair>(nextTabIndex(), getGrid()) {
@Override
public String getValue(EnergyOfferDTO energyOffer) {
return obtainPriceValue(colIndex, energyOffer, false);
}
@Override
public void doUpdate(int index, EnergyOfferDTO energyOffer, String value) {
if (value != null && !value.isEmpty()) {
// number format exceptions should be caught and handled by event bus's handle method
final double valueAsDouble = NumberFormat.getDecimalFormat().parse(value);
final BigDecimal price = BigDecimal.valueOf(valueAsDouble);
final List<OfferPriceMwPair> offerPriceCurve = energyOffer.getCurve();
final OfferPriceMwPair offerPriceMwPair = offerPriceCurve.get(colIndex);
if (offerPriceMwPair == null) { // we have a new price value
newOfferPriceMwPair.setPrice(price);
offerPriceCurve.add(newOfferPriceMwPair);
} else {
offerPriceMwPair.setPrice(price);
}
}
}
@Override
protected String getPropertyName() {
return "price";
}
@Override
protected Class<OfferPriceMwPair> getPropertyOwner() {
return OfferPriceMwPair.class;
}
};
} else {
priceColumn = new Column<EnergyOfferDTO, String>(new TextCell()) {
@Override
public String getValue(EnergyOfferDTO energyOffer) {
final String result = obtainPriceValue(colIndex, energyOffer, true);
return result;
}
};
}
return priceColumn;
}
private String obtainPriceValue(final int colIndex, EnergyOfferDTO energyOffer, boolean withCurrency) {
String result = "";
if (energyOffer != null) {
final List<OfferPriceMwPair> offerPriceCurve = energyOffer.getCurve();
final int numberOfPairs = offerPriceCurve.size();
if (colIndex < numberOfPairs) {
final OfferPriceMwPair offerPriceMwPair = offerPriceCurve.get(colIndex);
if (offerPriceMwPair != null) {
final BigDecimal price = offerPriceMwPair.getPrice();
if (price != null) {
final double value = price.doubleValue();
if (withCurrency) {
result = NumberFormat.getCurrencyFormat().format(value);
} else {
result = NumberFormat.getDecimalFormat().format(value);
}
}
}
}
}
return result;
}
protected Column<EnergyOfferDTO, String> generateMwColumn(final int colIndex, final OfferPriceMwPair newOfferPriceMwPair, DisplayMode currentDisplayMode) {
Column<EnergyOfferDTO, String> mwColumn;
if (isInEditMode(currentDisplayMode)) {
mwColumn = new BigDecimalValidatableColumn<EnergyOfferDTO, PriceMwPair>(nextTabIndex(), getGrid()) {
@Override
public String getValue(EnergyOfferDTO energyOffer) {
return obtainMwValue(colIndex, energyOffer);
}
@Override
public void doUpdate(int index, EnergyOfferDTO energyOffer, String value) {
if (value != null && !value.isEmpty()) {
// number format exceptions should be caught and handled by event bus's handle method
final double valueAsDouble = NumberFormat.getDecimalFormat().parse(value);
final BigDecimal mw = BigDecimal.valueOf(valueAsDouble);
final List<OfferPriceMwPair> offerPriceCurve = energyOffer.getCurve();
final OfferPriceMwPair offerPriceMwPair = offerPriceCurve.get(colIndex);
if (offerPriceMwPair == null) { // we have a new price value
newOfferPriceMwPair.setMw(mw);
offerPriceCurve.add(newOfferPriceMwPair);
} else {
offerPriceMwPair.setMw(mw);
}
}
}
@Override
protected String getPropertyName() {
return "mw";
}
@Override
protected Class<PriceMwPair> getPropertyOwner() {
return PriceMwPair.class;
}
};
} else {
mwColumn = new Column<EnergyOfferDTO, String>(new TextCell()) {
@Override
public String getValue(EnergyOfferDTO energyOffer) {
final String result = obtainMwValue(colIndex, energyOffer);
return result;
}
};
}
return mwColumn;
}
private String obtainMwValue(final int colIndex, EnergyOfferDTO energyOffer) {
String result = "";
if (energyOffer != null) {
final List<OfferPriceMwPair> offerPriceCurve = energyOffer.getCurve();
final int numberOfPairs = offerPriceCurve.size();
if (colIndex < numberOfPairs) {
final PriceMwPair offerPriceMwPair = offerPriceCurve.get(colIndex);
if (offerPriceMwPair != null) {
final BigDecimal mw = offerPriceMwPair.getMw();
if (mw != null) {
result = NumberFormat.getDecimalFormat().format(mw);
}
}
}
}
return result;
}
}