com.google.gwt.user.client.ui.FormPanel Maven / Gradle / Ivy
/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.user.client.ui;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.FormElement;
import com.google.gwt.event.shared.EventHandler;
import com.google.gwt.event.shared.GwtEvent;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.Command;
import com.google.gwt.user.client.DeferredCommand;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.ui.impl.FormPanelImpl;
import com.google.gwt.user.client.ui.impl.FormPanelImplHost;
/**
* A panel that wraps its contents in an HTML <FORM> element.
*
*
* This panel can be used to achieve interoperability with servers that accept
* traditional HTML form encoding. The following widgets (those that implement
* {@link com.google.gwt.user.client.ui.HasName}) will be submitted to the
* server if they are contained within this panel:
*
* - {@link com.google.gwt.user.client.ui.TextBox}
* - {@link com.google.gwt.user.client.ui.PasswordTextBox}
* - {@link com.google.gwt.user.client.ui.RadioButton}
* - {@link com.google.gwt.user.client.ui.SimpleRadioButton}
* - {@link com.google.gwt.user.client.ui.CheckBox}
* - {@link com.google.gwt.user.client.ui.SimpleCheckBox}
* - {@link com.google.gwt.user.client.ui.TextArea}
* - {@link com.google.gwt.user.client.ui.ListBox}
* - {@link com.google.gwt.user.client.ui.FileUpload}
* - {@link com.google.gwt.user.client.ui.Hidden}
*
* In particular, {@link com.google.gwt.user.client.ui.FileUpload} is
* only useful when used within a FormPanel, because the browser will
* only upload files using form submission.
*
*
*
*
Example
* {@example com.google.gwt.examples.FormPanelExample}
*
*/
@SuppressWarnings("deprecation")
public class FormPanel extends SimplePanel implements FiresFormEvents,
FormPanelImplHost {
/**
* Fired when a form has been submitted successfully.
*/
public static class SubmitCompleteEvent extends
GwtEvent {
/**
* The event type.
*/
private static Type TYPE;
/**
* Handler hook.
*
* @return the handler hook
*/
static Type getType() {
if (TYPE == null) {
TYPE = new Type();
}
return TYPE;
}
private String resultHtml;
/**
* Create a submit complete event.
*
* @param resultsHtml the results from submitting the form
*/
protected SubmitCompleteEvent(String resultsHtml) {
this.resultHtml = resultsHtml;
}
@Override
public final Type getAssociatedType() {
return TYPE;
}
/**
* Gets the result text of the form submission.
*
* @return the result html, or null if there was an error
* reading it
* @tip The result html can be null as a result of submitting a
* form to a different domain.
*/
public String getResults() {
return resultHtml;
}
@Override
protected void dispatch(SubmitCompleteHandler handler) {
handler.onSubmitComplete(this);
}
}
/**
* Handler for {@link FormPanel.SubmitCompleteEvent} events.
*/
public interface SubmitCompleteHandler extends EventHandler {
/**
* Fired when a form has been submitted successfully.
*
* @param event the event
*/
void onSubmitComplete(FormPanel.SubmitCompleteEvent event);
}
/**
* Fired when the form is submitted.
*/
public static class SubmitEvent extends GwtEvent {
/**
* The event type.
*/
private static Type TYPE = new Type();
/**
* Handler hook.
*
* @return the handler hook
*/
static Type getType() {
if (TYPE == null) {
TYPE = new Type();
}
return TYPE;
}
private boolean canceled = false;
/**
* Cancel the form submit. Firing this will prevent a subsequent
* {@link FormPanel.SubmitCompleteEvent} from being fired.
*/
public void cancel() {
this.canceled = true;
}
@Override
public final Type getAssociatedType() {
return TYPE;
}
/**
* Gets whether this form submit will be canceled.
*
* @return true if the form submit will be canceled
*/
public boolean isCanceled() {
return canceled;
}
@Override
protected void dispatch(FormPanel.SubmitHandler handler) {
handler.onSubmit(this);
}
/**
* This method is used for legacy support and should be removed when
* {@link FormHandler} is removed.
*
* @deprecated Use {@link FormPanel.SubmitEvent#cancel()} instead
*/
@Deprecated
void setCanceled(boolean canceled) {
this.canceled = canceled;
}
}
/**
* Handler for {@link FormPanel.SubmitEvent} events.
*/
public interface SubmitHandler extends EventHandler {
/**
*Fired when the form is submitted.
*
*
* The FormPanel must not be detached (i.e. removed from its parent
* or otherwise disconnected from a {@link RootPanel}) until the submission
* is complete. Otherwise, notification of submission will fail.
*
*
* @param event the event
*/
void onSubmit(FormPanel.SubmitEvent event);
}
/**
* Used with {@link #setEncoding(String)} to specify that the form will be
* submitted using MIME encoding (necessary for {@link FileUpload} to work
* properly).
*/
public static final String ENCODING_MULTIPART = "multipart/form-data";
/**
* Used with {@link #setEncoding(String)} to specify that the form will be
* submitted using traditional URL encoding.
*/
public static final String ENCODING_URLENCODED = "application/x-www-form-urlencoded";
/**
* Used with {@link #setMethod(String)} to specify that the form will be
* submitted using an HTTP GET request.
*/
public static final String METHOD_GET = "get";
/**
* Used with {@link #setMethod(String)} to specify that the form will be
* submitted using an HTTP POST request (necessary for {@link FileUpload} to
* work properly).
*/
public static final String METHOD_POST = "post";
private static int formId = 0;
private static FormPanelImpl impl = GWT.create(FormPanelImpl.class);
/**
* Creates a FormPanel that wraps an existing <form> element.
*
* This element must already be attached to the document. If the element is
* removed from the document, you must call
* {@link RootPanel#detachNow(Widget)}.
*
*
* The specified form element's target attribute will not be set, and the
* {@link FormSubmitCompleteEvent} will not be fired.
*
*
* @param element the element to be wrapped
*/
public static FormPanel wrap(Element element) {
// Assert that the element is attached.
assert Document.get().getBody().isOrHasChild(element);
FormPanel formPanel = new FormPanel(element);
// Mark it attached and remember it for cleanup.
formPanel.onAttach();
RootPanel.detachOnWindowClose(formPanel);
return formPanel;
}
/**
* Creates a FormPanel that wraps an existing <form> element.
*
* This element must already be attached to the document. If the element is
* removed from the document, you must call
* {@link RootPanel#detachNow(Widget)}.
*
*
* If the createIFrame parameter is set to true, then the wrapped
* form's target attribute will be set to a hidden iframe. If not, the form's
* target will be left alone, and the FormSubmitComplete event will not be
* fired.
*
*
* @param element the element to be wrapped
* @param createIFrame true to create an <iframe> element
* that will be targeted by this form
*/
public static FormPanel wrap(Element element, boolean createIFrame) {
// Assert that the element is attached.
assert Document.get().getBody().isOrHasChild(element);
FormPanel formPanel = new FormPanel(element, createIFrame);
// Mark it attached and remember it for cleanup.
formPanel.onAttach();
RootPanel.detachOnWindowClose(formPanel);
return formPanel;
}
private String frameName;
private Element synthesizedFrame;
/**
* Creates a new FormPanel. When created using this constructor, it will be
* submitted to a hidden <iframe> element, and the results of the
* submission made available via {@link SubmitCompleteHandler}.
*
*
* The back-end server is expected to respond with a content-type of
* 'text/html', meaning that the text returned will be treated as HTML. If any
* other content-type is specified by the server, then the result HTML sent in
* the onFormSubmit event will be unpredictable across browsers, and the
* {@link SubmitCompleteHandler#onSubmitComplete(com.google.gwt.user.client.ui.FormPanel.SubmitCompleteEvent)
* onSubmitComplete} event may not fire at all.
*
*
* @tip The initial implementation of FormPanel specified that the server
* respond with a content-type of 'text/plain'. This has been
* intentionally changed to specify 'text/html' because 'text/plain'
* cannot be made to work properly on all browsers.
*/
public FormPanel() {
this(Document.get().createFormElement(), true);
}
/**
* Creates a FormPanel that targets a {@link NamedFrame}. The target frame is
* not physically attached to the form, and must therefore still be added to a
* panel elsewhere.
*
*
* When the FormPanel targets an external frame in this way, it will not fire
* the FormSubmitComplete event.
*
*
* @param frameTarget the {@link NamedFrame} to be targetted
*/
public FormPanel(NamedFrame frameTarget) {
this(frameTarget.getName());
}
/**
* Creates a new FormPanel. When created using this constructor, it will be
* submitted either by replacing the current page, or to the named
* <iframe>.
*
*
* When the FormPanel targets an external frame in this way, it will not fire
* the FormSubmitComplete event.
*
*
* @param target the name of the <iframe> to receive the results of the
* submission, or null to specify that the current page
* be replaced
*/
public FormPanel(String target) {
super(Document.get().createFormElement());
setTarget(target);
}
/**
* This constructor may be used by subclasses to explicitly use an existing
* element. This element must be a <form> element.
*
*
* The specified form element's target attribute will not be set, and the
* {@link FormSubmitCompleteEvent} will not be fired.
*
*
* @param element the element to be used
*/
protected FormPanel(Element element) {
this(element, false);
}
/**
* This constructor may be used by subclasses to explicitly use an existing
* element. This element must be a <form> element.
*
*
* If the createIFrame parameter is set to true, then the wrapped
* form's target attribute will be set to a hidden iframe. If not, the form's
* target will be left alone, and the FormSubmitComplete event will not be
* fired.
*
*
* @param element the element to be used
* @param createIFrame true to create an <iframe> element
* that will be targeted by this form
*/
protected FormPanel(Element element, boolean createIFrame) {
super(element);
FormElement.as(element);
if (createIFrame) {
assert ((getTarget() == null) || (getTarget().trim().length() == 0)) : "Cannot create target iframe if the form's target is already set.";
// We use the module name as part of the unique ID to ensure that ids are
// unique across modules.
frameName = "FormPanel_" + GWT.getModuleName() + "_" + (++formId);
setTarget(frameName);
sinkEvents(Event.ONLOAD);
}
}
/**
* @deprecated Use {@link #addSubmitCompleteHandler} and
* {@link #addSubmitHandler} instead
*/
@Deprecated
public void addFormHandler(FormHandler handler) {
ListenerWrapper.WrappedOldFormHandler.add(this, handler);
}
/**
* Adds a {@link SubmitCompleteEvent} handler.
*
* @param handler the handler
* @return the handler registration used to remove the handler
*/
public HandlerRegistration addSubmitCompleteHandler(
SubmitCompleteHandler handler) {
return addHandler(handler, SubmitCompleteEvent.getType());
}
/**
* Adds a {@link SubmitEvent} handler.
*
* @param handler the handler
* @return the handler registration used to remove the handler
*/
public HandlerRegistration addSubmitHandler(SubmitHandler handler) {
return addHandler(handler, SubmitEvent.getType());
}
/**
* Gets the 'action' associated with this form. This is the URL to which it
* will be submitted.
*
* @return the form's action
*/
public String getAction() {
return getFormElement().getAction();
}
/**
* Gets the encoding used for submitting this form. This should be either
* {@link #ENCODING_MULTIPART} or {@link #ENCODING_URLENCODED}.
*
* @return the form's encoding
*/
public String getEncoding() {
return impl.getEncoding(getElement());
}
/**
* Gets the HTTP method used for submitting this form. This should be either
* {@link #METHOD_GET} or {@link #METHOD_POST}.
*
* @return the form's method
*/
public String getMethod() {
return getFormElement().getMethod();
}
/**
* Gets the form's 'target'. This is the name of the {@link NamedFrame} that
* will receive the results of submission, or null if none has
* been specified.
*
* @return the form's target.
*/
public String getTarget() {
return getFormElement().getTarget();
}
/**
* Fired when a form is submitted.
*
* @return true if the form is submitted, false if canceled
*/
public boolean onFormSubmit() {
return onFormSubmitImpl();
}
public void onFrameLoad() {
onFrameLoadImpl();
}
/**
* @deprecated Use the {@link HandlerRegistration#removeHandler} method on the
* object returned by and add*Handler method instead
*/
@Deprecated
public void removeFormHandler(FormHandler handler) {
ListenerWrapper.WrappedOldFormHandler.remove(this, handler);
}
/**
* Resets the form, clearing all fields.
*/
public void reset() {
impl.reset(getElement());
}
/**
* Sets the 'action' associated with this form. This is the URL to which it
* will be submitted.
*
* @param url the form's action
*/
public void setAction(String url) {
getFormElement().setAction(url);
}
/**
* Sets the encoding used for submitting this form. This should be either
* {@link #ENCODING_MULTIPART} or {@link #ENCODING_URLENCODED}.
*
* @param encodingType the form's encoding
*/
public void setEncoding(String encodingType) {
impl.setEncoding(getElement(), encodingType);
}
/**
* Sets the HTTP method used for submitting this form. This should be either
* {@link #METHOD_GET} or {@link #METHOD_POST}.
*
* @param method the form's method
*/
public void setMethod(String method) {
getFormElement().setMethod(method);
}
/**
* Submits the form.
*
*
* The FormPanel must not be detached (i.e. removed from its parent
* or otherwise disconnected from a {@link RootPanel}) until the submission is
* complete. Otherwise, notification of submission will fail.
*
*/
public void submit() {
// Fire the onSubmit event, because javascript's form.submit() does not
// fire the built-in onsubmit event.
if (!fireSubmitEvent()) {
return;
}
impl.submit(getElement(), synthesizedFrame);
}
@Override
protected void onAttach() {
super.onAttach();
if (frameName != null) {
// Create and attach a hidden iframe to the body element.
createFrame();
Document.get().getBody().appendChild(synthesizedFrame);
}
// Hook up the underlying iframe's onLoad event when attached to the DOM.
// Making this connection only when attached avoids memory-leak issues.
// The FormPanel cannot use the built-in GWT event-handling mechanism
// because there is no standard onLoad event on iframes that works across
// browsers.
impl.hookEvents(synthesizedFrame, getElement(), this);
}
@Override
protected void onDetach() {
super.onDetach();
// Unhook the iframe's onLoad when detached.
impl.unhookEvents(synthesizedFrame, getElement());
if (synthesizedFrame != null) {
// And remove it from the document.
Document.get().getBody().removeChild(synthesizedFrame);
synthesizedFrame = null;
}
}
// For unit-tests.
Element getSynthesizedIFrame() {
return synthesizedFrame;
}
private void createFrame() {
// Attach a hidden IFrame to the form. This is the target iframe to which
// the form will be submitted. We have to create the iframe using innerHTML,
// because setting an iframe's 'name' property dynamically doesn't work on
// most browsers.
Element dummy = Document.get().createDivElement();
dummy.setInnerHTML("