How Do I pass a @SimpleEvent name as a parameter to a private Function?

[gordonlu310]

@TIMAI2

But i will have many simpleevents and simplefunctions

Probably you have to hard code the functions, like this.

You have these events

@SimpleEvent(description = "Event raised when output returned")
  public void GotOutput(final String output) {
    EventDispatcher.dispatchEvent(this, "GotOutput", output);
  }

@SimpleEvent(description = "Event raised when output result")
  public void GotResult(final String output) {
    EventDispatcher.dispatchEvent(this, "GotOutput", output);
  }

and you do this.

if (something == "GotOutput") {
GotOutput(output);
} else if (something == "GotResult") {
GotResult(result);
}

[TIMAI2]

Yes I could build an if/else block or a switch-case statement to handle things.

[Taifun]

@TIMAI2

to identify which simplefunction was called

just pass that name to GotOutput and use it in the event as output parameter
Taifun

[Kevinkun]

Do you want to call a function / method by its name?

[TIMAI2]

@Kevinkun

Do you want to call a function / method by its name

That is the idea, but to pass it as a parameter ....

[gordonlu310]

Yes. Unfortunately in Java you cannot do

@gordonlu310

"GetOutput"(output);

and you cannot do

TextView "myTextViewCreatedJustNow" = new TextView;

and Tim also wants to

@TIMAI2

pass it as a parameter

as well. It would certainly have challenges.

[Aarush_Kumar]

@TIMAI2

Yes I could build an if/else block or a switch-case statement to handle things.

You might try reflection?

[gordonlu310]

Interesting.

Guide to Java Reflection | Baeldung

This particularly comes in handy when we don't know their names at compile time.

[Kevinkun]

Check this, call a function by its name and pass parameters:

[Free] Async Procedures | Extension

[TIMAI2]

@Aarush_Kumar

You might try reflection?

I have been thinking about this for sometime (this is a joke)

I have seen reflection being used for this on StackOverflow, but the application of the approach was way over my head.

[Kumaraswamy]

You wont be able to simply pass the method in Java, you could use easy conditions instead.
But still, a similar thing can be done:

package xyz.kumaraswamy.test;

import com.google.appinventor.components.annotations.SimpleEvent;
import com.google.appinventor.components.annotations.SimpleFunction;
import com.google.appinventor.components.runtime.AndroidNonvisibleComponent;
import com.google.appinventor.components.runtime.ComponentContainer;
import com.google.appinventor.components.runtime.EventDispatcher;

public class Test extends AndroidNonvisibleComponent {

    public Test(ComponentContainer container) {
        super(container.$form());
    }

    @SimpleEvent
    public void AppleFell(int apples) {
        EventDispatcher.dispatchEvent(this, "AppleFell", apples);
    }

    @SimpleEvent
    public void OrangeFell(int oranges) {
        EventDispatcher.dispatchEvent(this, "OrangeFell", oranges);
    }

    @SimpleFunction
    public void GetApples() throws Exception {
        doSomething("...", "AppleFell");
    }

    @SimpleFunction
    public void GetOranges() throws Exception {
        doSomething("....", "OrangeFell");
    }

    private void doSomething(String parameters, String whatEvent) throws Exception {
        int counts = parameters.length();
        // call the event with the name
        // that event has one arg int type
        getClass().getMethod(whatEvent,
                int.class).invoke(this, counts);
    }
}

// second one is event name (any event name in the class)
// but you wont be able to pass method as a paramter
doSomething("....", "OrangeFell");

[Aarush_Kumar]

@TIMAI2

I have seen reflection being used for this on StackOverflow, but the application of the approach was way over my head.

You might get an idea from dynamic components code it is made upon the principle of reflection

[TIMAI2]

OK, it looks like it will be easier to either:

1. Follow Taifun's suggestions in using one event, then select the correct event to run
2. Build an if/else or switch/case statement to select the correct event to run

Thanks to all for your ideas and input, it helped me see the wood from the trees

[Taifun]

@Taifun

only have one GotOutput event, which will fire for all those many simple functions

@SimpleEvent(description = "Event raised when output returned")
  public void GotOutput(final String output, String simpleFunction) {
    EventDispatcher.dispatchEvent(this, "GotOutput", output, simpleFunction);
  }

@SimpleFunction(description = "set parameters to get output")
  public void GetOutput() {
      String parameters = "some parameters";
      GetFunction(parameters);
  }

private void GetFunction(String parameters) {
//do something
//output to event:
GotOutput(output, "mySimpleFunction");
}

Taifun

[TIMAI2]

@Taifun

Works nicely

[TIMAI2]

and with the if/else method, I can use the specific event for the function call