RetroLambda with TextChangedListener

Question

Hi there I am new to RetroLambda. Right now I'm using it with Runnable, OnClickListener etc. The question is: is it possible to use RetroLambda with classes like onTextChangeListener? For example how to lambda this

etmessage.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            if (count > 0) {
                okmenubutton.setEnabled(true);
                okmenubutton.getIcon().setAlpha(255);
            } else {
                okmenubutton.setEnabled(false);
                okmenubutton.getIcon().setAlpha(130);
            }
        }

        @Override
        public void afterTextChanged(Editable s) {

        }
    });

Thank you.

If you are familiar with RxJava, you might want to look at RxBindings library from Jake Wharton. This library allows you to simply subscribe to one of the TextWatchers methods. — Marcel50506, Jul 28 '16 at 08:33

score 4 · Accepted Answer · answered Apr 03 '16 at 21:38

Retrolambda ports Java 8 features to previous JVM versions. When you're using a lambda instead of Runnable it's called automatic SAM conversion, where SAM stands for Single Abstract Method. It means that if you have an interface or an abstract class with a single abstract method you can replace it with a lambda with the same signature. TextWatcher has three abstract methods as you can see and it cannot be replaced with a lambda.

If you want to use lambdas you can define single-method interfaces for each TextWatcher method and implement helper methods that will accept these interfaces, one per method, create a TextWatcher that will delegate invocation to the interface, and add the TextWatcher to TextView.

RetroLambda with TextChangedListener

1 Answers1