GWT：处理复合单元格中的事件 [英] GWT: handling event in composite cell
问题描述
运行下面的代码，当我们点击单元格的按钮时，会实现对事件处理响应的弹出式窗口IF我们对CompositeCell匿名实现进行评论。
我一直在调试CompositeCell.onBrowserEvent（Context，Element，C，NativeEvent，ValueUpdater），因为我认为使用HTML表格标签的单元格布局的定义打破了GWT窗口小部件层次结构中的事件链，但并没有成功至今。
备注：代码的注释和未注释版本都实现了相同的GUI布局，这个例子只是为了表明我们在定制单元格内容时放松事件处理。
public class ActionCellTest实现EntryPoint {
private static final String SERVER_ERROR =+尝试联系服务器时发生错误。请检查您的网络
+连接，然后重试。;
private final GreetingServiceAsync greetingService = GWT.create（GreetingService.class）;
$ b $ public void onModuleLoad（）{
CellTable< Person>>>> cells = new LinkedList< HasCell< HasCell< Person>> cellTable< ActionCellTest.Person>（）;
; Person，？>>（）;
cells.add（new HasCellImpl（first name，new ActionCell.Delegate< Person>（）{
@Override
public void execute（Person object）{
Window.alert（object.getFirstName（））;
}
}））;
cells.add（new HasCellImpl（last名称，新的ActionCell.Delegate< ActionCellTest.Person>（）{
@Override
public void execute（Person object）{
Window.alert（object.getLastName（） ）;
}
}））;
CompositeCell< Person> cell = new CompositeCell< Person>（cells）{
@Override
public void render（Context context，Person value，SafeHtmlBuilder sb）{
sb.appendHtmlConstant（<表>< TBODY>< TR>中）; （HasCell< Person，？> hasCell：cells）{
render（context，value，sb，hasCell）;
}
sb.appendHtmlConstant（< / tr>< / tbody>< / table>）;
}
@覆盖
保护< X> void render（Context context，Person value，SafeHtmlBuilder sb，HasCell< Person，X> hasCell）{
Cell< X> cell = hasCell.getCell（）;
sb.appendHtmlConstant（< td>）;
cell.render（context，hasCell.getValue（value），sb）;
sb.appendHtmlConstant（< / td>）;
$ b @Override
protected Element getContainerElement（Element parent）{
return parent.getFirstChildElement（）。getFirstChildElement（）。getFirstChildElement（）;
}
};
table.addColumn（new TextColumn< ActionCellTest.Person>（）{
@Override
public String getValue（ActionCellTest.Person object）{
return object.getFirstName （）++ object.getLastName（）;
}
}，name）;
table.addColumn（new Column< Person，Person>（cell）{
@Override
public Person getValue（ActionCellTest.Person object）{
返回对象;
}
}，composite）;
LinkedList< Person> data = new LinkedList< ActionCellTest.Person>（）;
data.add（新人（Amy，Reed））;
data.add（新人（Tim，Gardner））;
table.setRowData（data）;
RootPanel.get（）。add（table）;
}
private class HasCellImpl实现HasCell< Person，Person> {
private ActionCell< Person> FCELL;
$ b $ public HasCellImpl（String text，Delegate< Person> delegate）{
fCell = new ActionCell< Person>（text，delegate）;
}
@Override
public Cell< Person> getCell（）{
return fCell;
}
@Override
public FieldUpdater< Person，Person> getFieldUpdater（）{
return null;
}
@Override
public Person getValue（Person object）{
return object;
}
}
私人类Person {
private String fFirstName;
private String fLastName;
public Person（String first，String last）{
fFirstName = first;
fLastName = last;
}
public String getFirstName（）{
return fFirstName;
}
public String getLastName（）{
return fLastName;
这是一个已知问题，将在即将到来的GWT 2.5中解决（大约几周）： http://code.google.com/p/google-web-toolkit/issues/detail?id=5714
（in平均的时间，你可以跑掉干线或尝试backporting更改）
CompositeCell let us customize the content of a table cell's in GWT using Java. We can put almost any other group of widget within the table's cell and layout them as we want. Problem is that if we used the html tags to define the layout of the CompositeCell as yet another table (see CompositeCell anonymous class implementation bellow) we loose the event handling for the components of the cell :(.
Running the following code, when we click in the buttons of the cell will realize the popup in response of the event handling IF WE COMMENT the CompositeCell anonymous implementation.
I've been debugging CompositeCell.onBrowserEvent(Context, Element, C, NativeEvent, ValueUpdater) because i think that the definition of the cell layout using HTML table tags breaks the event chain within GWT widgets hierarchy but haven't been successful so far.
Remark: both commented and uncommented versions of the code realize the same GUI layout. This example just intent to show that we loose event handling when customizing cell's content.
public class ActionCellTest implements EntryPoint {
private static final String SERVER_ERROR = "An error occurred while " + "attempting to contact the server. Please check your network "
+ "connection and try again.";
private final GreetingServiceAsync greetingService = GWT.create(GreetingService.class);
public void onModuleLoad() {
CellTable<Person> table = new CellTable<ActionCellTest.Person>();
final List<HasCell<Person, ?>> cells = new LinkedList<HasCell<Person, ?>>();
cells.add(new HasCellImpl("first name", new ActionCell.Delegate<Person>() {
@Override
public void execute(Person object) {
Window.alert(object.getFirstName());
}
}));
cells.add(new HasCellImpl("last name", new ActionCell.Delegate<ActionCellTest.Person>() {
@Override
public void execute(Person object) {
Window.alert(object.getLastName());
}
}));
CompositeCell<Person> cell = new CompositeCell<Person>(cells) {
@Override
public void render(Context context, Person value, SafeHtmlBuilder sb) {
sb.appendHtmlConstant("<table><tbody><tr>");
for (HasCell<Person, ?> hasCell : cells) {
render(context, value, sb, hasCell);
}
sb.appendHtmlConstant("</tr></tbody></table>");
}
@Override
protected <X> void render(Context context, Person value, SafeHtmlBuilder sb, HasCell<Person, X> hasCell) {
Cell<X> cell = hasCell.getCell();
sb.appendHtmlConstant("<td>");
cell.render(context, hasCell.getValue(value), sb);
sb.appendHtmlConstant("</td>");
}
@Override
protected Element getContainerElement(Element parent) {
return parent.getFirstChildElement().getFirstChildElement().getFirstChildElement();
}
};
table.addColumn(new TextColumn<ActionCellTest.Person>() {
@Override
public String getValue(ActionCellTest.Person object) {
return object.getFirstName() + " " + object.getLastName();
}
}, "name");
table.addColumn(new Column<Person, Person>(cell) {
@Override
public Person getValue(ActionCellTest.Person object) {
return object;
}
}, "composite");
LinkedList<Person> data = new LinkedList<ActionCellTest.Person>();
data.add(new Person("Amy", "Reed"));
data.add(new Person("Tim", "Gardner"));
table.setRowData(data);
RootPanel.get().add(table);
}
private class HasCellImpl implements HasCell<Person, Person> {
private ActionCell<Person> fCell;
public HasCellImpl(String text, Delegate<Person> delegate) {
fCell = new ActionCell<Person>(text, delegate);
}
@Override
public Cell<Person> getCell() {
return fCell;
}
@Override
public FieldUpdater<Person, Person> getFieldUpdater() {
return null;
}
@Override
public Person getValue(Person object) {
return object;
}
}
private class Person {
private String fFirstName;
private String fLastName;
public Person(String first, String last) {
fFirstName = first;
fLastName = last;
}
public String getFirstName() {
return fFirstName;
}
public String getLastName() {
return fLastName;
}
}
}
This is a known issue which will be fixed in the upcoming GWT 2.5 (a matter of weeks): http://code.google.com/p/google-web-toolkit/issues/detail?id=5714
(in the mean time, you can run off trunk or try backporting the change)
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