Run the code in main threa after completeion of IO thread process kotlin coroutines-CodePudding

 override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

  lifecycleScope.launch(Dispatchers.Main) {
            networkviewModel.productist.collectLatest {
                when (it) {
                    Resource.Empty -> {
                        Log.e("product", ""   "empty")
                    }
                    is Resource.Failure -> {
                        Log.e("product", ""   "failure")
                    }
                    Resource.Loading -> {

                    }
                    is Resource.Success -> {
                        val response = it.value
                        Log.e("test","success response")
                        val products: List<Products> = response.data
                        val variants: List<Variants> = response.data.map { it.variants }.flatten()
                        lifecycleScope.launch(Dispatchers.IO) {
                            productRoom.insertProducts(products)
                            productRoom.insertVariants(variants)
                            val subcategoryid = SubCategoryList(response.data[0].subcategory_id!!.toInt())
                            productRoom.insertSubCat(subcategoryid)
                        }
                        subcat_id = response.data[0].subcategory_id!!.toInt()
                        roomviewModel.productFlow.collectLatest{
                            Log.e("test","flow success from network room")
                            //    Log.e("test",it.toString())
                            LoadingUtils.hideDialog()
                            proadapter.setMutableArraylist(it)
                            proadapter.notifyDataSetChanged()
                        }
                    }
                }
            }
        }
}

i got error of FATAL EXCEPTION: main Process: com.store.pasumainew, PID: 13125 java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

because in Resource.Success -> collect called before the completion of IO thread process

I want to complete the IO thread and afterwards collect the value from room

CodePudding user response：

Try to use withContext(Dispatchers.IO) before collecting, it will be suspended until all operations are complete:

withContext(Dispatchers.IO) {                
    productRoom.insertProducts(products)
    productRoom.insertVariants(variants)
    val subcategoryid = SubCategoryList(response.data[0].subcategory_id!!.toInt())
    productRoom.insertSubCat(subcategoryid)
}
// ... collecting code

Btw you don't need to use Dispatchers.Main to launch the main coroutine, by default lifecycleScope works on Dispatchers.Main context, so you can just write:

lifecycleScope.launch {
    // ...
}

CodePudding user response：

The crash is in this line of code

val subcategoryid = SubCategoryList(response.data[0].subcategory_id!!.toInt())

try changing it to this

val subcategoryid = SubCategoryList(response.data[0]?.subcategory_id?.toInt())?:0