Mutation and update cache

Now let's do the integration part. Open TaskFragment.kt and add the following code at the bottom of the file:

TaskFragment.kt

Copy
    private fun toggleTodoMutationCloud(todoId: Int, completeFlag: Boolean){
        // Init Query
        toggleTodoMutation = ToggleTodoMutation.builder().id(todoId).isCompleted(completeFlag).build()
        getMyTodosQuery = GetMyTodosQuery.builder().build()

        val index = listItems?.indexOfFirst { todo ->  todo.id() == todoId}
        var todos = listItems?.toMutableList()?.get(index!!)


        val todo = GetMyTodosQuery.Todo(
            todos?.__typename()!!,
            todos.id(),
            todos.title(),
            todos.created_at(),
            completeFlag)

        var updatedList = listItems?.toMutableList()
        updatedList?.set(index!!, todo)



        // Optimistic Update
        Network.apolloClient
            .apolloStore()
            .writeOptimisticUpdatesAndPublish(GetMyTodosQuery(), GetMyTodosQuery.Data(mutableListOf(todo)), UUID.randomUUID()).execute()
        getMyTodosQueryLocal()


        // Apollo runs query on background thread
        Network.apolloClient.mutate(toggleTodoMutation)?.enqueue(object : ApolloCall.Callback<ToggleTodoMutation.Data>() {
            override fun onFailure(error: ApolloException) {
                Log.d("Todo", error.toString() )
            }

            override fun onResponse(@NotNull response: Response<ToggleTodoMutation.Data>) {
                Network.apolloClient.apolloStore().write(toggleTodoMutation, response.data()!!)
                getMyTodosQueryLocal()
            }
        })
    }

We are making an optimistic update to the the apolloClient.apolloStore() and then doing the actual mutation over the cloud. Lets add this in our updateTaskCompleteStatus action handler,

Copy
    override fun updateTaskCompleteStatus(taskId: Int, completeFlag: Boolean) {
-        // Todo : Method for updating the complete status for the task
+        toggleTodoMutationCloud(taskId, completeFlag)
    }

We already have the getMyTodosQueryLocal which queries the data from local cache and updates the list.