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GWT - HTMLPanel Widget
Introduction
The HTMLPanel widget represents a panel that contains HTML, and which can attach child widgets to identified elements within that HTML.
Class Declaration
Following is the declaration for com.google.gwt.user.client.ui.HTMLPanel class −
public class HTMLPanel extends ComplexPanel
Class Constructors
Sr.No. | Constructor & Description |
---|---|
1 |
HTMLPanel(SafeHtml safeHtml) Initializes the panel's HTML from a given SafeHtml object. |
2 |
HTMLPanel(java.lang.String html) Creates an HTML panel with the specified HTML contents inside a DIV element. |
3 |
HTMLPanel(java.lang.String tag, java.lang.String html) Creates an HTML panel whose root element has the given tag, and with the specified HTML contents. |
Class Methods
Sr.No. | Function name & Description |
---|---|
1 |
void add(Widget widget, Element elem) Adds a child widget to the panel, contained within an HTML element. |
2 |
void add(Widget widget, java.lang.String id) Adds a child widget to the panel, contained within the HTML element specified by a given id. |
3 |
void addAndReplaceElement(Widget widget, Element toReplace) Adds a child widget to the panel, replacing the HTML element. |
4 |
void addAndReplaceElement(Widget widget, java.lang.String id) Adds a child widget to the panel, replacing the HTML element specified by a given id. |
5 |
static java.lang.String createUniqueId() A helper method for creating unique IDs for elements within dynamically- generated HTML. |
6 |
Element getElementById(java.lang.String id) Finds an element within this panel by its id. |
Methods Inherited
This class inherits methods from the following classes −
com.google.gwt.user.client.ui.UIObject
com.google.gwt.user.client.ui.Widget
com.google.gwt.user.client.ui.Panel
com.google.gwt.user.client.ui.ComplexPanel
java.lang.Object
HTMLPanel Widget Example
This example will take you through simple steps to show usage of a HTMLPanel Widget in GWT. Follow the following steps to update the GWT application we created in GWT - Create Application chapter −
Step | Description |
---|---|
1 | Create a project with a name HelloWorld under a package com.tutorialspoint as explained in the GWT - Create Application chapter. |
2 | Modify HelloWorld.gwt.xml, HelloWorld.css, HelloWorld.html and HelloWorld.java as explained below. Keep rest of the files unchanged. |
3 | Compile and run the application to verify the result of the implemented logic. |
Following is the content of the modified module descriptor src/com.tutorialspoint/HelloWorld.gwt.xml.
<?xml version = "1.0" encoding = "UTF-8"?> <module rename-to = 'helloworld'> <!-- Inherit the core Web Toolkit stuff. --> <inherits name = 'com.google.gwt.user.User'/> <!-- Inherit the default GWT style sheet. --> <inherits name = 'com.google.gwt.user.theme.clean.Clean'/> <!-- Specify the app entry point class. --> <entry-point class = 'com.tutorialspoint.client.HelloWorld'/> <!-- Specify the paths for translatable code --> <source path = 'client'/> <source path = 'shared'/> </module>
Following is the content of the modified Style Sheet file war/HelloWorld.css.
body { text-align: center; font-family: verdana, sans-serif; } h1 { font-size: 2em; font-weight: bold; color: #777777; margin: 40px 0px 70px; text-align: center; }
Following is the content of the modified HTML host file war/HelloWorld.html.
<html> <head> <title>Hello World</title> <link rel = "stylesheet" href = "HelloWorld.css"/> <script language = "javascript" src = "helloworld/helloworld.nocache.js"> </script> </head> <body> <h1>HTMLPanel Widget Demonstration</h1> <div id = "gwtContainer"></div> </body> </html>
Let us have following content of Java file src/com.tutorialspoint/HelloWorld.java which will demonstrate use of HTMLPanel widget.
package com.tutorialspoint.client; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.user.client.ui.DecoratorPanel; import com.google.gwt.user.client.ui.HTMLPanel; import com.google.gwt.user.client.ui.RootPanel; public class HelloWorld implements EntryPoint { public void onModuleLoad() { String htmlString = "This is a <b>HTMLPanel</b> containing" +" html contents. " +" <i>By putting some fairly large contents in the middle" +" and setting its size explicitly, it becomes a scrollable area" +" within the page, but without requiring the use of an IFRAME.</i>" +" <u>Here's quite a bit more meaningless text that will serve" +" to make this thing scroll off the bottom of its visible area." +" Otherwise, you might have to make it really, really" +" small in order to see the nifty scroll bars!</u>"; HTMLPanel htmlPanel = new HTMLPanel(htmlString); DecoratorPanel panel = new DecoratorPanel(); panel.add(htmlPanel); // Add the widgets to the root panel. RootPanel.get().add(panel); } }
Once you are ready with all the changes done, let us compile and run the application in development mode as we did in GWT - Create Application chapter. If everything is fine with your application, this will produce following result −