CustomLanguageHint - Parameter hint

Hello,

It's relatively simple.

findElementForParameterInfo() and findElementForUpdatingParameterInfo() should return owner element of parameters. Usually something like a call expression.

showParameterInfo() should show the hints UI and can be implemented as a simple call to context.showHint().

updateUI() should set UI state by calling context.setupUIComponentPresentation() method.

In ParameterInfoUtils.getCurrentParameterIndex() is useful to find index of current parameter under cursor.

You can check my implementation for a custom language:

https://github.com/casteng/i-pascal/blob/master/plugin/src/editor/PascalParameterInfoHandler.java

Home this helps.

Yes, It helped me to understand it, thank you...today I've finally gave it another try and got it working.

Although I must admit it took me a couple of hours for a dumb reason... haven't realized that I have to implement both create and update context returning the PsiElement to get it shown at first... was trying to get the create context working first with no idea, why nothing is visible and not realizing that hint's update is not user triggered action, but a visual update... :)

But if may I ask for the last detail, for some yet unknown reason to me, those hints are rendered in a column one under another instead of a single row, don't you have any idea why that happened?

This is an example on which I'm trying it... might it be because the handler is typed as  ParameterInfoHandler<GmlFunction, String> so it requires an actual PsiElement which will contain all parameters? I'll try it probably tomorrow, but not sure if that might be the cause.

public GmlFunction findElementForParameterInfo(@NotNull CreateParameterInfoContext context) {
    PsiElement element = context.getFile().findElementAt(context.getOffset());
    GmlFunction call = PsiTreeUtil.getParentOfType(element, GmlFunction.class);

    ArrayList<String> mm = new ArrayList<>();
    mm.add("test");
    mm.add("asd");

    context.setItemsToShow(mm.toArray());
    return call;
}

public void updateUI(String s, @NotNull ParameterInfoUIContext context) {
    context.setupUIComponentPresentation(s, 0, s.length(), s.equals("test"), false, false, context.getDefaultParameterColor()
    );
}

public void showParameterInfo(@NotNull GmlFunction element, @NotNull CreateParameterInfoContext context) {
    context.showHint(element, element.getTextRange().getStartOffset(), this);
}

public GmlFunction findElementForUpdatingParameterInfo(@NotNull UpdateParameterInfoContext context) {
    PsiElement element = context.getFile().findElementAt(context.getOffset());
    GmlFunction call = PsiTreeUtil.getParentOfType(element, GmlFunction.class);

    return call;
}

In your example "test" and "asd" should be rendered under each other. It's as intended as the possibility to add multiple items is provided to support overloaded methods. Those hints are rendered this way.