lambda expression should be final FOR LOOP

Question

I am trying to retrieve some items from an activity list in order to show them with JavaFX but at the same time I also want to be able to delete these items if I click on the item's button. How can I distinguish which button I clicked in order to delete the right row? I'm trying to assign to the button the lambda expression but apparently it doesn't work in a for loop. Any suggestion on how to fix this?

   gridPane = new GridPane();

    String path = "image.png";
    items = new ArrayList<>();

    items.add("Activity 1");
    items.add("Activity 2");
    items.add("Activity 3");

    for (int i=0; i<items.size(); i++) {
        gridPane.add(new Text(items.get(i)), 1, i);
        gridPane.add(new JFXButton("", new ImageView(path)),2,i);
        (JFXButton)gridPane.setOnMouseClicked(e -> deleteActivity(gridPane.getRowIndex(i)));
    }

Variable used in lambda expression should be final or effectively final referred to the "i" in the last row — Jasmine, Mar 10 '19 at 11:46
Possible duplicate of [Variable used in lambda expression should be final or effectively final](https://stackoverflow.com/questions/34865383/variable-used-in-lambda-expression-should-be-final-or-effectively-final) — Benjamin Urquhart, Mar 10 '19 at 11:50
Define a variable `int ii = i;` inside the loop, and use that in the lambda instead. — Andy Turner, Mar 10 '19 at 11:52
@AndyTurner now I get "Inconvertible types; cannot cast 'void' to 'com.jfoenix.controls.JFXButton'" because of the JFXButton casting — Jasmine, Mar 10 '19 at 12:01
I'm casting JFXButton to gridPane, as it's visible in the code I'm adding a new button to the gridPane — Jasmine, Mar 10 '19 at 12:10

score 1 · Accepted Answer · answered Mar 10 '19 at 12:10

1

I asuume you wanted :

JFXButton button = new JFXButton("", new ImageView(path);   
gridPane.add(button),2,i);
button.setOnMouseClicked(e -> deleteActivity(gridPane.getRowIndex(i)));

answered Mar 10 '19 at 12:10

c0der

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lambda expression should be final FOR LOOP

1 Answers1