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dataconnect: demo: add "Delete" button an "List Items" screen. (#6585)
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‎firebase-dataconnect/demo/firebase/dataconnect/connector/operations.gql

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@@ -49,6 +49,26 @@ query GetItemByKey(
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}
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}
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query GetAllItems @auth(level: PUBLIC) {
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items: zwda6x9zyys {
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id
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string
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int
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int64
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float
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boolean
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date
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timestamp
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any
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}
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}
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mutation DeleteItemByKey(
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$key: zwda6x9zyy_Key!
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) @auth(level: PUBLIC) {
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zwda6x9zyy_delete(key: $key)
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}
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# This mutation exists only as a workaround for b/382688278 where the following
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# compiler error will otherwise result when compiling the generated code:
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# Serializer has not been found for type 'java.util.UUID'. To use context

‎firebase-dataconnect/demo/src/main/AndroidManifest.xml

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@@ -16,13 +16,12 @@ See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<manifest xmlns:android="http://schemas.android.com/apk/res/android"
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xmlns:tools="http://schemas.android.com/tools">
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<manifest xmlns:android="http://schemas.android.com/apk/res/android">
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<application
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android:name=".MyApplication"
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android:label="Data Connect Minimal Demo"
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android:theme="@style/Theme.AppCompat.NoActionBar"
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android:theme="@style/Theme.AppCompat"
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>
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<activity android:name=".MainActivity" android:exported="true">
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</intent-filter>
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</activity>
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<activity
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android:name=".ListItemsActivity"
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android:label="List Items"
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/>
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</application>
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</manifest>

‎firebase-dataconnect/demo/src/main/kotlin/com/google/firebase/dataconnect/minimaldemo/ListItemsActivity.kt

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/*
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* Copyright 2024 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.firebase.dataconnect.minimaldemo
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import android.os.Bundle
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import android.view.LayoutInflater
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import android.view.View
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import android.view.ViewGroup
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import androidx.activity.viewModels
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import androidx.appcompat.app.AppCompatActivity
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import androidx.lifecycle.flowWithLifecycle
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import androidx.lifecycle.lifecycleScope
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import androidx.recyclerview.widget.DividerItemDecoration
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import androidx.recyclerview.widget.LinearLayoutManager
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import androidx.recyclerview.widget.RecyclerView
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import com.google.firebase.dataconnect.minimaldemo.connector.GetAllItemsQuery
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import com.google.firebase.dataconnect.minimaldemo.databinding.ActivityListItemsBinding
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import com.google.firebase.dataconnect.minimaldemo.databinding.ListItemBinding
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import kotlinx.coroutines.flow.collectLatest
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import kotlinx.coroutines.launch
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class ListItemsActivity : AppCompatActivity() {
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private lateinit var myApplication: MyApplication
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private lateinit var viewBinding: ActivityListItemsBinding
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private val viewModel: ListItemsViewModel by viewModels { ListItemsViewModel.Factory }
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override fun onCreate(savedInstanceState: Bundle?) {
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super.onCreate(savedInstanceState)
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myApplication = application as MyApplication
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viewBinding = ActivityListItemsBinding.inflate(layoutInflater)
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viewBinding.recyclerView.also {
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val linearLayoutManager = LinearLayoutManager(this)
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it.layoutManager = linearLayoutManager
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val dividerItemDecoration = DividerItemDecoration(this, linearLayoutManager.layoutDirection)
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it.addItemDecoration(dividerItemDecoration)
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}
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setContentView(viewBinding.root)
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lifecycleScope.launch {
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if (viewModel.loadingState == ListItemsViewModel.LoadingState.NotStarted) {
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viewModel.getItems()
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}
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viewModel.stateSequenceNumber.flowWithLifecycle(lifecycle).collectLatest {
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onViewModelStateChange()
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}
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}
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}
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private fun onViewModelStateChange() {
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val items = viewModel.result?.getOrNull()
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val exception = viewModel.result?.exceptionOrNull()
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val loadingState = viewModel.loadingState
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if (loadingState == ListItemsViewModel.LoadingState.InProgress) {
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viewBinding.statusText.text = "Loading Items..."
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viewBinding.statusText.visibility = View.VISIBLE
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viewBinding.recyclerView.visibility = View.GONE
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viewBinding.recyclerView.adapter = null
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} else if (items !== null) {
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viewBinding.statusText.text = null
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viewBinding.statusText.visibility = View.GONE
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viewBinding.recyclerView.visibility = View.VISIBLE
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val oldAdapter = viewBinding.recyclerView.adapter as? RecyclerViewAdapterImpl
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if (oldAdapter === null || oldAdapter.items !== items) {
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viewBinding.recyclerView.adapter = RecyclerViewAdapterImpl(items)
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}
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} else if (exception !== null) {
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viewBinding.statusText.text = "Loading items FAILED: $exception"
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viewBinding.statusText.visibility = View.VISIBLE
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viewBinding.recyclerView.visibility = View.GONE
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viewBinding.recyclerView.adapter = null
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} else {
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viewBinding.statusText.text = null
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viewBinding.statusText.visibility = View.GONE
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viewBinding.recyclerView.visibility = View.GONE
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}
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}
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private class RecyclerViewAdapterImpl(val items: List<GetAllItemsQuery.Data.ItemsItem>) :
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RecyclerView.Adapter<RecyclerViewViewHolderImpl>() {
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override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerViewViewHolderImpl {
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val binding = ListItemBinding.inflate(LayoutInflater.from(parent.context), parent, false)
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return RecyclerViewViewHolderImpl(binding)
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}
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override fun getItemCount() = items.size
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override fun onBindViewHolder(holder: RecyclerViewViewHolderImpl, position: Int) {
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holder.bindTo(items[position])
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}
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}
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private class RecyclerViewViewHolderImpl(private val binding: ListItemBinding) :
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RecyclerView.ViewHolder(binding.root) {
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fun bindTo(item: GetAllItemsQuery.Data.ItemsItem) {
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binding.id.text = item.id.toString()
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binding.name.text = item.string
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}
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}
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}

‎firebase-dataconnect/demo/src/main/kotlin/com/google/firebase/dataconnect/minimaldemo/ListItemsViewModel.kt

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/*
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* Copyright 2024 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.firebase.dataconnect.minimaldemo
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import android.util.Log
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import androidx.annotation.MainThread
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import androidx.lifecycle.ViewModel
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import androidx.lifecycle.ViewModelProvider
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import androidx.lifecycle.ViewModelProvider.AndroidViewModelFactory.Companion.APPLICATION_KEY
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import androidx.lifecycle.viewModelScope
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import androidx.lifecycle.viewmodel.initializer
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import androidx.lifecycle.viewmodel.viewModelFactory
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import com.google.firebase.dataconnect.minimaldemo.connector.GetAllItemsQuery
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import com.google.firebase.dataconnect.minimaldemo.connector.execute
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import kotlinx.coroutines.CancellationException
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import kotlinx.coroutines.Deferred
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import kotlinx.coroutines.ExperimentalCoroutinesApi
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import kotlinx.coroutines.Job
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import kotlinx.coroutines.async
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import kotlinx.coroutines.flow.MutableStateFlow
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import kotlinx.coroutines.flow.StateFlow
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import kotlinx.coroutines.flow.asStateFlow
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import kotlinx.coroutines.launch
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class ListItemsViewModel(private val app: MyApplication) : ViewModel() {
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// Threading Note: _state and the variables below it may ONLY be accessed (read from and/or
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// written to) by the main thread; otherwise a race condition and undefined behavior will result.
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private val _stateSequenceNumber = MutableStateFlow(111999L)
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val stateSequenceNumber: StateFlow<Long> = _stateSequenceNumber.asStateFlow()
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var result: Result<List<GetAllItemsQuery.Data.ItemsItem>>? = null
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private set
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private var job: Job? = null
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val loadingState: LoadingState =
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job.let {
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if (it === null) {
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LoadingState.NotStarted
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} else if (it.isCancelled || it.isCompleted) {
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LoadingState.Completed
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} else {
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LoadingState.InProgress
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}
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}
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enum class LoadingState {
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NotStarted,
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InProgress,
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Completed,
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}
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@OptIn(ExperimentalCoroutinesApi::class)
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@MainThread
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fun getItems() {
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// If there is already a "get items" operation in progress, then just return and let the
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// in-progress operation finish.
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if (loadingState == LoadingState.InProgress) {
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return
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}
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// Start a new coroutine to perform the "get items" operation.
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val job: Deferred<List<GetAllItemsQuery.Data.ItemsItem>> =
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viewModelScope.async { app.getConnector().getAllItems.execute().data.items }
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this.result = null
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this.job = job
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_stateSequenceNumber.value++
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// Update the internal state once the "get items" operation has completed.
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job.invokeOnCompletion { exception ->
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// Don't log CancellationException, as documented by invokeOnCompletion().
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if (exception is CancellationException) {
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return@invokeOnCompletion
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}
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val result =
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if (exception !== null) {
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Log.w(TAG, "WARNING: Getting all items FAILED: $exception", exception)
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Result.failure(exception)
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} else {
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val items = job.getCompleted()
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Log.i(TAG, "Retrieved all items ${items.size} items")
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Result.success(items)
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}
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viewModelScope.launch {
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if (this@ListItemsViewModel.job === job) {
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this@ListItemsViewModel.result = result
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this@ListItemsViewModel.job = null
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_stateSequenceNumber.value++
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}
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}
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}
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}
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companion object {
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private const val TAG = "ListItemsViewModel"
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val Factory: ViewModelProvider.Factory = viewModelFactory {
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initializer { ListItemsViewModel(this[APPLICATION_KEY] as MyApplication) }
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}
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}
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}

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