Accept JavaScript callbacks as arguments?

[cashapp]

Accept JavaScript callbacks as arguments?

Hmm... I think the best way to do that currently is to define a global JS object with a method that calls the desired callback, then use the Duktape.proxy() method to create an object that can be called from Java. You could also use the evaluate method to invoke the callback directly: Duktape.evaluate("setTimeout(10)");

We don't provide a way to call a free (non-member) function from Java.

[tyler-whitman]

@ntrrgc did you end up finding a good way to implement setTimeout?

@szurbrigg would it be possible to provide a little more clarification on what you mean?

I currently exposed "setTimeout" as a global to JS which I have implemented as so:

public class SetTimeout implements ISetTimeout {

    private Handler handler;
    private HashMap<Integer, Runnable> timerMap;

    public SetTimeout(Handler handler, HashMap<Integer, Runnable> timerMap) {
        this.handler = handler;
        this.timerMap = timerMap;
    }

    @Override
    public int setTimeout(Object function, int delay) {
        Runnable task = new Runnable() {
            @Override
            public void run() {
                //need to callback the function here
            }
        };
        int id = task.hashCode();
        timerMap.put(id, task);
        handler.postDelayed(task, delay);
        return id;
    }
}

Then calling:
duktape.set("setTimeout", ISetTimeout.class, new SetTimeout(handler, timerMap));

Where ISetTimeout is defined as:
public interface ISetTimeout { int setTimeout(Object function, int delay); }

Obviously this crashes because of the function being passed as a parameter to the method. What is the recommended way around this?

[ntrrgc]

@twhit093 No, I ended up rolling my own JavaScript bridge for Android that allows holding references to JS objects from Java (including functions) and therefore is capable of these things. https://github.com/ntrrgc/jsvm