Vaadin Web应用开发教程(21):UI组件-Embedded组件

Embedded组件支持者浏览器中嵌入媒体对象，如图像，动画等其它浏览器支持的媒体类型。Embedded组件内容在Vaadin中是作为资源来管理的

[java]
Embedded image = new Embedded("Yes, logo:",
new ClassResource("vaadin-logo.png", this));
main.addComponent(image);

Embedded image = new Embedded("Yes, logo:",
new ClassResource("vaadin-logo.png", this));
main.addComponent(image);

The Embedded.TYPE_OBJECT 支持浏览器嵌入媒体，目前只支持显示Flas易做图，它的MIME类型为application/x-shockwave-flash.

[java]
// Create a Shockware Flash resource
final ClassResource flashResource =
    new ClassResource("itmill_spin.swf", getApplication());

// Display the resource in a Embedded compoant
final Embedded embedded =
    new Embedded("Embedded Caption", flashResource);

// This is the default type, but we set it anyway.
embedded.setType(Embedded.TYPE_OBJECT);

// This is recorgnized automatically, but set it anyway.
embedded.setMimeType("application/x-shockwave-flash");

// Create a Shockware Flash resource
final ClassResource flashResource =
new ClassResource("itmill_spin.swf", getApplication());

// Display the resource in a Embedded compoant
final Embedded embedded =
new Embedded("Embedded Caption", flashResource);

// This is the default type, but we set it anyway.
embedded.setType(Embedded.TYPE_OBJECT);

// This is recorgnized automatically, but set it anyway.
embedded.setMimeType("application/x-shockwave-flash");
可以通过方法setParameter 为对象设置参数。

Embedded.TYPE_IMAGE 用来显示图像，通常无需明确指定其类型。 Embedded 组件缺省未定义宽度和高度，因此可以自动适应所显示图像的大小，如果需要使用滚动条，可以在Panel中嵌入Embedded组件。
如果需要显示动态生成的图像，比如从StreamResource显示图像并且显示对象发生变化，就需要在浏览器重新加载图像，不同浏览器处理缓存Cache的方法不同，因此保险的方法是为动态生成的图像使用不同的文件名，
并在创建图像使用setCacheTime 将Cache时间设为0.

[java]
// Create the stream resource with some initial filename.
StreamResource imageResource =
    new StreamResource(imageSource, "initial-filename.png",
                       getApplication());

// Instruct browser not to cache the image.
imageResource.setCacheTime(0);

// Display the image in an Embedded component.
Embedded embedded = new Embedded("", imageResource);

// Create the stream resource with some initial filename.
StreamResource imageResource =
new StreamResource(imageSource, "initial-filename.png",
getApplication());

// Instruct browser not to cache the image.
imageResource.setCacheTime(0);

// Display the image in an Embedded component.
Embedded embedded = new Embedded("", imageResource);
刷新图像使用requestRepaint() 方法。

[java]
// This needs to be done, but is not sufficient.
embedded.requestRepaint();

// Generate a filename with a timestamp.
SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmssSSS");
String filename = "myfilename-" + df.format(new Date()) + ".png";

// Replace the filename in the resource.
imageResource.setFilename(makeImageFilename());

// This needs to be done, but is not sufficient.
embedded.requestRepaint();

// Generate a filename with a timestamp.
SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmssSSS");
String filename = "myfilename-" + df.format(new Date()) + ".png";

// Replace the filename in the resource.
imageResource.setFilename(makeImageFilename());
Embedded.TYPE_BROWSER在iframe中显示一个外部链接。

[java]
URL url = new URL("http://dev.vaadin.com/");
Embedded browser = new Embedded("", new ExternalResource(url));
browser.setType(Embedded.TYPE_BROWSER);
main.addComponent(browser);

URL url = new URL("http://dev.vaadin.com/");
Embedded browser = new Embedded("", new ExternalResource(url));
browser.setType(Embedded.TYPE_BROWSER);
main.addComponent(browser);

补充：Web开发 , 其他 ,