Question: I am trying to use a GitHub library (MeowBottomNavigation)in Android Studio.But its written in kotlin and i cant use the listeners in it.
The only thing which is given is this 

```
bottomNavigation.setOnShowListener {
}

bottomNavigation.setOnClickMenuListener {
}

```

the suggestions shows to use 

(Function1) 

i am not sure as to how to implement this in java . Any help will be appreciated.

I am familiar with java but the library is written in Kotlin. Is there any way to use these listeners in java?

```
bottomNavigation.setOnClickMenuListener(new 
Function1<MeowBottomNavigation.Model, Unit>() {
        @Override
        public Unit invoke(MeowBottomNavigation.Model p1) {
            int i = p1.getId();
            switch (i){
                case 4:
                    Toast.makeText(UserMainActivity.this, i, Toast.LENGTH_SHORT).show();
                    break;
                case  1:
                    Toast.makeText(UserMainActivity.this, i, Toast.LENGTH_SHORT).show();
                    break;
                case 2:
                    Toast.makeText(UserMainActivity.this, i, Toast.LENGTH_SHORT).show();
                    break;
                case 3:
                    Toast.makeText(UserMainActivity.this, i, Toast.LENGTH_SHORT).show();
                    break;
            }
            return Unit.INSTANCE;
        }
    });

```

Answer: 
Function0, Function1, Function2, ... FunctionN are higher-order functions in kotlin.

After converting to java, your click listeners become something like below.

```
// Set Menu Click Listener 
bottomNavigation.setOnClickMenuListener(new Function1<MeowBottomNavigation.Model, Unit>() {
        @Override
        public Unit invoke(MeowBottomNavigation.Model p1) {
            return Unit.INSTANCE;
        }
    });

// Set Menu Show listener
bottomNavigation.setOnShowListener(new Function1<MeowBottomNavigation.Model, Unit>() {
        @Override
        public Unit invoke(MeowBottomNavigation.Model s) {
            return Unit.INSTANCE;
        }
    });

```
use
implementation 'com.etebarian:meow-bottom-navigation-java:1.2.0'

for details watch
<https://www.youtube.com/watch?v=MiphbOtSyWY>