How to specify a button to open an URL?

问题:

I want to write a web application that triggers the default email client of the user to send an email.

Thus, I created a Link, that leads to an URL conforming to the mailto URI scheme (http://en.wikipedia.org/wiki/Mailto):

Link emailLink = new Link("Send Email", 
    new ExternalResource("mailto:[e-mail]"));

However, instead of using a Link, I want to provide a Button that allows to trigger the respective functionality. But, for buttons I cannot set an ExternalResource to be opened.

Does anybody know to solve this problem for Buttons, or how to create a Link that looks and behaves exactly like a button? I also tried some CCS modification but did not manage the task by myself. I also found some solutions for former Vaadin versions (https://vaadin.com/forum/#!/thread/69989), but, unfortunately they do not work for Vaadin 7.

回答1:

I remember solving a similar problem using a ResourceReference.

Button emailButton = new Button("Email");
content.addComponent(emailButton);
Resource res = new ExternalResource("mailto:[e-mail]");
final ResourceReference rr = ResourceReference.create(res, content, "email");

emailButton.addClickListener(new Button.ClickListener() {

    @Override
    public void buttonClick(ClickEvent event) {
        Page.getCurrent().open(rr.getURL(), null);
    }
});

回答2:

For solving similar issue, I applied previously:

    String email="[e-mail]";
    Link l=new Link();
    l.setResource(new ExternalResource("mailto:" + email));
    l.setCaption("Send email to " + email);
    addComponent(l);

回答3:

After some further tries a managed to adapt the proposed LinkButton solution from https://vaadin.com/forum/#!/thread/69989 for Vaadin 7:

public class LinkButton extends Button {
    public LinkButton(final String url, String caption) {
        super(caption);
        setImmediate(true);
        addClickListener(new Button.ClickListener() {
            private static final long serialVersionUID = -2607584137357484607L;

            @Override
            public void buttonClick(ClickEvent event) {
                LinkButton.this.getUI().getPage().open(url, "_blank");
            }
        });
    }
}

However, this solution is still not perfect as it causes the opening of a popup window being blocked by some web browsers.