Tag: Android

Dont’ know what’s going wrong but scratching my head for the last couple of hours. I have a SharedViewModel which has a LiveData of type List. When the First Fragment observes and updates the LiveData everything works good within the First Fragment but after navigating to second fragment and observing the same Livedata it doesn’t work. The value of the LiveData shows an empty array.
What am I doing wrong? Please help. Thanks in advance.

SharedViewModel code

    private val _cartItemList = MutableLiveData<MutableList<RestaurantItem>>()
    val cartItemList: LiveData<List<RestaurantItem>> = _cartItemList.map { it as          
    List<RestaurantItem> }
    
    init {
        _cartItemList.value = mutableListOf()
    }


    fun addItemToCartItemsList(item: RestaurantItem) {
        _cartItemList.value?.add(item)
        Log.i("CART", "${cartItemList.value}")
    }

    fun removeItemFromCartItemsList(item: RestaurantItem) {
        _cartItemList.value?.remove(item)
        Log.i("CART", "${cartItemList.value}")
    }

First Fragment code

 override fun onClick(restaurantItem: RestaurantItem, view: View) {
        val button = (view as Button)


        if (button.text.startsWith("A")) {
            _viewModel.addItemToCartItemsList(restaurantItem)
            button.text = getString(R.string.remove)
            _snackBar?.show()


        } else if (button.text.startsWith("R")) {
            _viewModel.removeItemFromCartItemsList(restaurantItem)
            button.text = getString(R.string.add)
            _viewModel.isCartEmpty().observe(viewLifecycleOwner, Observer {
                if (it) _snackBar?.dismiss()
            })
        }


    }

Second Fragment where the updates are not working when same LiveData is observed, it only shows an empty array

Second Fragment Code

 private fun setupCartItems() {
        _viewModel.cartItemList.observe(viewLifecycleOwner, Observer {
            Log.i("LIST", "$it")
        })
        //Logcat Logs I/LIST: ()

    }