Question

Is there a way to put raw HTML inside of a Label widget with GWT? The constructor and setText() methods automatically escape the text for HTML (so < appears as <, etc).

What I need is something like:

String matched = "two";
List<String> values = Arrays.asList("one", "two", "three");
StringBuilder sb = new StringBuilder();
for (String v : values){
  if (v.equals(matched)){
    sb.append("<b>" + v + "<b>");
  } else {
    sb.append(v);
  }
  sb.append(", ");
}
Label label = new Label();
label.setRawText(sb.toString());
//div contains the following HTML: "one, <b>two</b>, three, "

I want to output a comma-separated list of Strings, but I want one of those Strings to be bolded. Thanks.

Answer 1

Sorry, I’m going to answer my own question because I found what I was looking for.

The SafeHtmlBuilder class is perfect for this. You tell it what strings you want to escape and what strings you do not want to escape. It works like StringBuilder because you call append methods:

String matched = "two";
List<String> values = Arrays.asList("one", "two", "three <escape-me>");
SafeHtmlBuilder builder = new SafeHtmlBuilder();
for (String v : values){
  if (v.equals(matched)){
    builder.appendHtmlConstant("<b>");
    builder.appendEscaped(v);
    builder.appendHtmlConstant("</b>");
  } else {
    builder.appendEscaped(v);
  }
  builder.appendEscaped(", ");
}
HTML widget = new HTML();
widget.setHTML(builder.toSafeHtml());
//div contains the following HTML: "one, <b>two</b>, three &lt;escape-me&gt;, "

Note that the appendHtmlConstant method expects a complete tag. So if you want to add attributes to the tag whose values change during runtime, it won’t work. For example, this won’t work (it throws an IllegalArgumentException):

String url = //...
SafeHtmlBuilder builder = new SafeHtmlBuilder();
builder.appendHtmlConstant("<a href=\""); //throws IllegalArgumentException
builder.appendEscaped(url);
builder.appendHtmlConstant("\">link</a>");