这是我们如何使用编辑器/HasEditorError 和 ConstraintViolations 的简单示例。我还包含了一个来自我们的 ValueBoxEditorDecorator 的示例，它允许我们布局错误消息。
我们的活动
@Override
public void onSave() {
RequestFactoryEditorDriver<DashboardModelProxy, ?> driver = display.getDriver();
RequestContext context = driver.flush();
context.fire(new Receiver<Void>() {
@Override
public void onSuccess(Void response) {
Place previousPlace = clientFactory.getPlaceController().getPreviousPlace();
clientFactory.getPlaceController().goTo(previousPlace);
}
@Override
public void onFailure(ServerFailure error) {
display.showError(error.getMessage());
}
@Override
public void onConstraintViolation(Set<ConstraintViolation<?>> violations) {
display.getDriver().setConstraintViolations(violations);
}
});
}
从我们的角度来看样本。
/**
* Name component for the name of the analytics operation.
* This also implements {@link HasEditorErrors so it can show
* constraint violations when an error occurs.
*/
@UiField
ValueBoxEditorDecorator<String> name;
使用错误位置的 UIBinder 示例。
<t:ValueBoxEditorDecorator errorLocation="RIGHT" ui:field="name">
<t:valuebox>
<g:TextBox />
</t:valuebox>
</t:ValueBoxEditorDecorator>
我们正在使用的 ValueBoxEditorDecorator。
import java.util.List;
import com.google.gwt.dom.client.Style.Display;
import com.google.gwt.editor.client.EditorError;
import com.google.gwt.editor.client.HasEditorErrors;
import com.google.gwt.editor.client.IsEditor;
import com.google.gwt.editor.client.adapters.TakesValueEditor;
import com.google.gwt.editor.ui.client.adapters.ValueBoxEditor;
import com.google.gwt.uibinder.client.UiChild;
import com.google.gwt.uibinder.client.UiConstructor;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.ValueBoxBase;
import com.google.gwt.user.client.ui.ValueListBox;
/**
* This is a copy of the original ValueBoxEditorDecorator in the gwt source The
* reason we are not using it is because it did not support laying out the error
* panel in a different location.
*
*
* A simple decorator to display leaf widgets with an error message.
* <p>
* <h3>Use in UiBinder Templates</h3>
* <p>
* The decorator may have exactly one ValueBoxBase added though an
* <code><e:valuebox></code> child tag.
* <p>
* For example:
*
* <pre>
* @UiField
* ValueBoxEditorDecorator<String> name;
* </pre>
*
* <pre>
* <e:ValueBoxEditorDecorator ui:field='name'>
* <e:valuebox>
* <g:TextBox />
* </e:valuebox>
* </e:ValueBoxEditorDecorator>
* </pre>
*
* @param <T>
* the type of data being edited
*/
public class ValueListBoxEditorDecorator<T> extends Composite implements HasEditorErrors<T>, IsEditor<TakesValueEditor<T>> {
/**
* The location of the text relative to the paging buttons.
*/
public static enum ErrorPanelLocation {
LEFT, RIGHT;
}
SimplePanel contents = new SimplePanel();
@Ignore
Label errorLabel = new Label();
HorizontalPanel layout = new HorizontalPanel();
private TakesValueEditor<T> editor;
/**
* Constructs a ValueBoxEditorDecorator.
*/
@UiConstructor
public ValueListBoxEditorDecorator(ErrorPanelLocation errorLocation) {
initWidget(layout);
setStyleName("gwt-ValueBoxEditorDecorator");
errorLabel.setStyleName("gwt-ValueBoxEditorDecorator-error");
errorLabel.getElement().getStyle().setDisplay(Display.NONE);
if (errorLocation == ErrorPanelLocation.RIGHT) {
layout.add(contents);
layout.add(errorLabel);
} else {
layout.add(errorLabel);
layout.add(contents);
}
}
/**
* Constructs a ValueBoxEditorDecorator using a {@link ValueBoxBase} widget
* and a {@link ValueBoxEditor} editor.
*
* @param widget
* the widget
* @param editor
* the editor
*/
public ValueListBoxEditorDecorator(ValueListBox<T> widget, TakesValueEditor<T> editor) {
this(ErrorPanelLocation.RIGHT);
contents.add(widget);
this.editor = editor;
}
/**
* Returns the associated {@link ValueBoxEditor}.
*
* @return a {@link ValueBoxEditor} instance
* @see #setEditor(ValueBoxEditor)
*/
public TakesValueEditor<T> asEditor() {
return editor;
}
/**
* Sets the associated {@link ValueBoxEditor}.
*
* @param editor
* a {@link ValueBoxEditor} instance
* @see #asEditor()
*/
public void setEditor(ValueBoxEditor<T> editor) {
this.editor = editor;
}
/**
* Set the widget that the EditorPanel will display. This method will
* automatically call {@link #setEditor}.
*
* @param widget
* a {@link ValueBoxBase} widget
*/
@UiChild(limit = 1, tagname = "valuebox")
public void setValueBox(ValueBoxBase<T> widget) {
contents.add(widget);
setEditor(widget.asEditor());
}
public void clearErrors() {
errorLabel.setText("");
errorLabel.getElement().getStyle().setDisplay(Display.NONE);
}
/**
* The default implementation will display, but not consume, received errors
* whose {@link EditorError#getEditor() getEditor()} method returns the
* Editor passed into {@link #setEditor}.
*
* @param errors
* a List of {@link EditorError} instances
*/
public void showErrors(List<EditorError> errors) {
StringBuilder sb = new StringBuilder();
for (EditorError error : errors) {
if (error.getEditor().equals(editor)) {
sb.append("\n").append(error.getMessage());
}
}
if (sb.length() == 0) {
clearErrors();
return;
}
errorLabel.setText(sb.substring(1));
errorLabel.getElement().getStyle().setDisplay(Display.INLINE_BLOCK);
}
}