this is my code fragmentproduct
class FragmentProduct : Fragment() {
var list = ArrayList<Category>()
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view = inflater.inflate(R.layout.fragment_product, container, false)
getCategory()
return view
}
private fun getCategory(){
var queue: RequestQueue = Volley.newRequestQueue(requireContext())
var request = JsonArrayRequest(Request.Method.GET, "http://192.168.1.10/login/apicategory.php", null, Response.Listener{ response->
for (s in 0..response.length() - 1){
var job = response.getJSONObject(s)
var id = job.getInt("id")
var name = job.getString("name")
var photo = job.getString("photo").replace("localhost", "192.168.1.10")
list.add(Category(id, name, photo))
var adapterku = CategoryProduct(requireContext(), list)
recycler.layoutManager = LinearLayoutManager(requireContext())
recycler.adapter = adapterku
}
}, Response.ErrorListener { error ->
Log.d("categoryEr", error.toString())
})
queue.add(request)
}
}
I get an error in the product fragment and every time I click on the product it immediately closes the app, and there is no error in the code
Fragment isn't attached to context when onCreateView gets called. You should call getCategory in onCreate instead. See this.
Related
Here is, what I'm trying to do:
A Switch is turned on, starting a service in another thread (works fine so far)
When this service is successful, it should then start another function within the main thread
I don't mind whether the function is called directly by the service or the service is returning a "success"-value to the main thread, what then starts the next function from there.
Here is, what the important parts of the code looks like:
Main thread:
class SendNotif : AppCompatActivity() {
val context = this
private lateinit var Switch: Switch
// Start LocationService when the switch is on
Switch.setOnCheckedChangeListener { buttonView, isChecked ->
if (isChecked) {
Toast.makeText(context, "Starting LocationService", Toast.LENGTH_SHORT).show()
Intent(applicationContext, LocationService::class.java).apply {
action = LocationService.ACTION_START
startService(this)
}
} else {
Toast.makeText(context, "Stopping LocationService", Toast.LENGTH_SHORT).show()
Intent(applicationContext, LocationService::class.java).apply {
action = LocationService.ACTION_STOP
startService(this)
}
}
}
}
fun InitiateMessage() {
// This is the function, that is supposed to start after the LocationService
}
}
This is the LocationService. After being successful, the function InitiateMessage() should start.
class LocationService: Service() {
private val serviceScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
private lateinit var locationClient: LocationClient
var lat = 0.0F
var long = 0.0F
override fun onBind(p0: Intent?): IBinder? {
return null
}
override fun onCreate() {
super.onCreate()
locationClient = DefaultLocationClient(
applicationContext,
LocationServices.getFusedLocationProviderClient(applicationContext)
)
}
// Start or stop the service
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
when(intent?.action) {
ACTION_START -> start()
ACTION_STOP -> stop()
}
return super.onStartCommand(intent, flags, startId)
}
private fun start() {
// Starting notification
val notification = NotificationCompat.Builder(this, "location")
.setContentTitle("Tracking location...")
.setContentText("Location: null")
.setSmallIcon(R.drawable.ic_launcher_background)
// Can't swipe this notification away
.setOngoing(true)
val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
// Starting the location updates
locationClient
// Every 10 seconds
.getLocationUpdates(10000L)
.catch { e -> e.printStackTrace() }
.onEach { location ->
lat = location.latitude.toString().toFloat() // .takeLast(3) // taking only the last 3 digits
long = location.longitude.toString().toFloat() // .takeLast(3)
val updatedNotification = notification.setContentText(
"Location: ($lat, $long)"
)
// notificationManager.notify(1, updatedNotification.build())
// Geofence
MyGeofence(lat, long)
}
.launchIn(serviceScope)
// startForeground(1, notification.build())
}
private fun stop() {
// Stopping the notification
stopForeground(true)
// Stopping the location service
stopSelf()
}
override fun onDestroy() {
super.onDestroy()
serviceScope.cancel()
}
companion object {
const val ACTION_START = "ACTION_START"
const val ACTION_STOP = "ACTION_STOP"
}
fun MyGeofence(lat : Float, long : Float){
val context = this
var db = DataBaseHandler(context)
var data = db.readData()
// Setting the accuracy of the geofence
val acc = 2
val safelat : Double = data.get(0).LocLat.toFloat().round(acc)
val safelong = data.get(0).LocLong.toFloat().round(acc) // .take(acc).take(acc)
val h = Handler(context.mainLooper)
if(safelat == lat.toFloat().round(acc) && safelong == long.toFloat().round(acc)){
h.post(Runnable { Toast.makeText(context, "You have reached your safe refuge! " + lat.toFloat().round(acc) + " " + long.toFloat().round(acc), Toast.LENGTH_LONG).show() })
// ToDo: Right hereafter the function InitiateMessage() should start
}
else{
h.post(Runnable { Toast.makeText(context, "You are still in great danger! " + lat.toFloat().round(acc) + " " + long.toFloat().round(acc), Toast.LENGTH_LONG).show() })
}
}
fun Float.round(decimals: Int): Double {
var multiplier = 1.0
repeat(decimals) { multiplier *= 10 }
return round(this * multiplier) / multiplier
}
}
So far, I tried it with a Looper, which did not work.
java.lang.RuntimeException: Can't create handler inside thread Thread[DefaultDispatcher-worker-1,5,main] that has not called Looper.prepare()
But I guess the far easier way would be a returned value by the service. How do I implement this, and how do I start the next function through this returned value?
I solved my problem with an observe-function and a companion object, that is a MutableLiveData.
The companion object is placed inside the main thread:
companion object {
// var iamsafe: Boolean = false
val iamsafe: MutableLiveData<Boolean> by lazy {
MutableLiveData<Boolean>()
}
}
The observe-function is placed within onCreate:
val safeObserver = Observer<Boolean> { newState ->
Toast.makeText(context, "Initiating message to my mate.", Toast.LENGTH_SHORT).show()
InitiateMessage()
}
iamsafe.observe(this, safeObserver)
The companion is changed in the second thread like this:
SendNotif.iamsafe.postValue (true)
Main Fragment:
here were initializing the recyclerview and the viewmodel and getting the data to submit to the adapter:
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val binding: FragmentMainBinding = FragmentMainBinding.inflate(inflater, container, false)
this.binding = FragmentMainBinding.inflate(layoutInflater)
dataFromViewModel = arrayListOf()
setupViewModel()
setupList()
setupView()
return binding.root;
}
private fun setupView() {
viewLifecycleOwner.lifecycleScope.launchWhenCreated {
viewModel.listData.collectLatest {
Log.e("Output Frg", it.toString())
if (!dataFromViewModel.contains(it)) {
dataFromViewModel.add(it)
mainAdapter.submitData(it)
mainAdapter.notifyDataSetChanged()
Log.e(TAG, "setupView: ${mainAdapter.repos.toString()}", )
}
}
}
}
private fun setupList() {
mainAdapter = MainAdapter()
val gridLayoutManager: GridLayoutManager = GridLayoutManager(context, 2)
binding.recyclerview.apply {
layoutManager = gridLayoutManager
adapter = mainAdapter
}
// mainAdapter.addLoadStateListener { loadState ->
//
// if (loadState.refresh is LoadState.Loading && !flag) {
// binding.progressbar.visibility = View.VISIBLE
// flag = true
// } else {
// binding.progressbar.visibility = View.GONE
// }
// }
}
private fun setupViewModel() {
viewModel =
ViewModelProvider(
this,
ViewModelFactory(RetrofitService.getApiService())
)[MainViewModel::class.java]
}
Main ViewModel:
here were just calling the postdatasource function and adding it to the listData value
class MainViewModel(private val apiService: RetrofitService) : ViewModel() {
val listData = Pager(PagingConfig(pageSize = 6)) {
PostDataSource(apiService)
}.flow.cachedIn(viewModelScope)
}
PostDataSource:
Here, we have extended PostDataSource with PagingSource which will implement a suspend load function which will help us to load the data.
PostDataSource also takes a primary constructor parameter APIService. PostDataSource acts here as a repository and the load function gets the data from the API.
Since the load function is a suspend function, we can call other suspend functions inside it without any issues which we created in APIService.
In the PostDataSource, we take two parameters one of integer type and other of the data type we have to load on the list item. The integer parameter represents the page number here.
Here, we get the page number from params and assign it to nextPage variable using param.key and if it returns null, we set a default value 1.
We also do the API call and get assign the response to the response variable using APIService which we passed as a constructor parameter to PostDataSource class.
After doing all the operations with the successful response, we return the LoadResult.Page object here with the required data and it something went wrong we use LoadResult.Error.
We are also passing null as the next key if there is no corresponding data in that direction.
class PostDataSource(private val apiService: RetrofitService) : PagingSource<Int, repo>() {
override suspend fun load(params: LoadParams<Int>): LoadResult<Int, repo> {
try {
val currentLoadingPageKey = params.key ?: 1
val response = apiService.getListData(currentLoadingPageKey)
val responseData = mutableListOf<repo>()
var repos : List<repo>
val data = response
responseData.addAll(data)
Log.e(TAG, "load: $responseData", )
val prevKey = if (currentLoadingPageKey == 1) null else currentLoadingPageKey - 1
return LoadResult.Page(
data = responseData,
prevKey = prevKey,
nextKey = currentLoadingPageKey.plus(1)
)
} catch (e: Exception) {
return LoadResult.Error(e)
}
}
override fun getRefreshKey(state: PagingState<Int, repo>): Int? {
return state.anchorPosition?.let { anchorPosition ->
val anchorPage = state.closestPageToPosition(anchorPosition)
anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
}
}
// fun getAllrepos() = retrofitService.getAllrepos()
}
MainAdapter:
Now, we will update the MainListAdapter. We will extend the MainListAdapter with PagingDataAdapter and the PagingDataAdapter will take the type of data we need to display in the list and the ViewHolder.
It also takes a DiffUtil callback, as a parameter to its primary constructor which helps the PagingDataAdapter to update the items if they are changed or updated. And DiffUtil callback is used because they are more performant.
Now, the MainListAdapter looks like,
class MainAdapter : PagingDataAdapter<repo, MainAdapter.ViewHolder>(DiffCallBack) , Filterable {
private lateinit var Repos : List<repo>
class ViewHolder(view: View, mlistener: onItemClickListener) : RecyclerView.ViewHolder(view)
private lateinit var mlistener: onItemClickListener
interface onItemClickListener {
fun OnItemClick(position: Int)
}
var repos: MutableList<repo> = ArrayList()
private var reposFull: MutableList<repo> = ArrayList()
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.itemView.findViewById<TextView>(R.id.title).text = getItem(position)?.name
Log.e(TAG,"name ${holder.itemView.findViewById<TextView>(R.id.title).text}", )
Glide.with(holder.itemView.context)
.load(getItem(position)?.owner?.avatar_url)
.into(holder.itemView.findViewById(R.id.imgCircle))
// val repo = repos[position]
//
//
// val mainViewHolder: ViewHolder = holder as ViewHolder
// mainViewHolder.itemView Title?.text = repo.name
// mainViewHolder.Image?.let {
// Glide.with(holder.itemView.context).load(repo.owner.avatar_url).into(
// it
// )
// }
}
fun submitList(list: PagingData<repo>) {
Repos = list as List<repo>
notifyDataSetChanged()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder(
LayoutInflater
.from(parent.context)
.inflate(R.layout.repo_layout, parent, false), mlistener
)
}
fun setOnItemClickListener(listener: onItemClickListener) {
mlistener = listener
}
object DiffCallBack : DiffUtil.ItemCallback<repo>() {
override fun areItemsTheSame(oldItem: repo, newItem: repo): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: repo, newItem: repo): Boolean {
return oldItem == newItem
}
}
// class MainViewHolder(itemView: View, listener: onItemClickListener) : RecyclerView.ViewHolder(itemView) {
// var Title: TextView? =
// itemView.findViewById<View>(com.lau.google_rep.R.id.title) as TextView
// var Image: ImageView? =
// itemView.findViewById<View>(com.lau.google_rep.R.id.imgCircle) as ImageView
//
// init {
// itemView.setOnClickListener {
// listener.OnItemClick(adapterPosition)
// }
// }
// }
override fun getFilter(): Filter {
return exampleFilter
}
private val exampleFilter: Filter = object : Filter() {
override fun performFiltering(constraint: CharSequence?): FilterResults? {
val filteredList: MutableList<repo> = ArrayList()
if (constraint == null || constraint.length == 0) {
filteredList.addAll(reposFull)
} else {
val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
for (item in reposFull) {
if (item.name.toLowerCase().contains(filterPattern)) {
filteredList.add(item)
}
}
}
Log.d(TAG, "publishResults: $filteredList")
val results = FilterResults()
results.values = filteredList
return results
}
#SuppressLint("NotifyDataSetChanged")
override fun publishResults(constraint: CharSequence?, results: FilterResults) {
repos.clear()
(results.values as? Collection<repo>)?.let { repos.addAll(it) }
notifyDataSetChanged()
}
}
}
retrofit service:
interface RetrofitService {
// #Headers("Authorization: token ")
#GET("repos")
suspend fun getListData(#Query("page") pageNumber: Int): List<repo>
companion object{
private val moshi = Moshi.Builder()
.add(KotlinJsonAdapterFactory())
.build()
fun getApiService() = Retrofit.Builder()
.baseUrl("https://api.github.com/orgs/google/")
.addConverterFactory(MoshiConverterFactory.create(moshi))
.build()
.create(RetrofitService::class.java)
}
}
I'm trying to pass a constantly updating variable "message" across my Jetpack Composables. I have a draggable box that tracks the coordinates of the box but I'm trying to send the real-time data through a TCP connection. However, I noticed that the current coordinate of the draggable box isn't passing through to the other Composable or the socket -only the same value is passed despite message changing continuously due to me dragging the box. Also, the moment dataSendButton() is pressed, the createDragImage() and its draggable box stops animating/running.
var message = "" // global Android send message
class MainActivity : ComponentActivity() {
private var textView: TextView? = null
dataSendButton()
createDragImage()
...
}
}
}
#Composable
fun createDragImage(){
val context = LocalContext.current
...
Box() {
var offsetX by remember { mutableStateOf(0f) }
var offsetY by remember { mutableStateOf(0f) }
Box(
Modifier
.offset { IntOffset(offsetX.roundToInt(), offsetY.roundToInt()) }
.background(Color.Transparent)
.size(150.dp)
.border(BorderStroke(4.dp, SolidColor(Color.Red)))
.pointerInput(Unit) {
detectDragGestures { change, dragAmount ->
change.consumeAllChanges()
offsetX = someConstantX
offsetY += dragAmount.y
message = offsetY.toString()
...
#Composable
fun dataSendButton() {
val context = LocalContext.current
...
Button(
onClick = {
// **ISSUE: message in this composable is not getting updated with message value from createDragImage()
val b1 = MainActivity.TCPconnector_client(context, message)
b1.execute()
},
{
Text(text = "Send Data", color = Color.White, fontSize = 20.sp)
}
}
}
}
}
It is because that is not how you store state in Compose.
Change the declaration of the variable.
var message by mutableStateOf(...)
Then the changes to it will trigger a recomposition, and so the rest of the code should remain the same. It is always recommended to store the state holders in a viewmodel, and pass the viewmodel around instead.
This is a working code with viewmodel
class MainActivity : ComponentActivity() {
private var textView: TextView? = null
val vm by viewmodels<MViewModel>()
dataSendButton(vm.message, vm:: onMessageChange)
createDragImage(vm.message)
...
}
}
}
#Composable
fun createDragImage(message: String, onMessageChange: (String) -> Unit){
val context = LocalContext.current
...
Box() {
var offsetX by remember { mutableStateOf(0f) }
var offsetY by remember { mutableStateOf(0f) }
Box(
Modifier
.offset { IntOffset(offsetX.roundToInt(), offsetY.roundToInt()) }
.background(Color.Transparent)
.size(150.dp)
.border(BorderStroke(4.dp, SolidColor(Color.Red)))
.pointerInput(Unit) {
detectDragGestures { change, dragAmount ->
change.consumeAllChanges()
offsetX = someConstantX
offsetY += dragAmount.y
onMessageChange (offsetY.toString())
...
#Composable
fun dataSendButton(message: String) {
val context = LocalContext.current
...
Button(
onClick = {
// **ISSUE: message in this composable is not getting updated with message value from createDragImage() // This seems to be an error. Calling a Composable from onClick?
val b1 = MainActivity.TCPconnector_client(context, message)
b1.execute()
},
{
Text(text = "Send Data", color = Color.White, fontSize = 20.sp)
}
}
}
}
}
class MViewModel: ViewModel(){
var message by mutableStateOf("")
private set //do not allow external modifications to ensure consistency
fun onMessageChange (newMessage: String){
message = newMessage
}
}
Note this is the ideal way of doing such implementation. However, for your specific case, if you do not need to access it anywhere else, only changing the declaration as described in the second line of the answer should do
Thanks
I wrote a simple temperature converter app, everything is working fine except when user leaves EditText blank/null but selects one of the radio buttons, The App crashes.
Here is the Kotlin Code:
class MainActivity : AppCompatActivity() {
lateinit var etTemp: EditText
lateinit var radioGroup: RadioGroup
lateinit var btnConverter :Button
lateinit var tempConverted: TextView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
title = "Zeeshan's Temperature Converter"
etTemp = findViewById(R.id.etTemp)
radioGroup = findViewById(R.id.radioGroup)
btnConverter = findViewById(R.id.btnConverter)
tempConverted = findViewById(R.id.tempConverted)
btnConverter.setOnClickListener {
val id = radioGroup.checkedRadioButtonId
val radioButton = findViewById<RadioButton>(id)
if (radioButton == findViewById(R.id.radioC)){
val temp =etTemp.text.toString().toInt()
val result = temp * 9/5 + 32
tempConverted.setText(result.toString())
}
else if (radioButton == findViewById(R.id.radioF)){
val tempy =etTemp.text.toString().toInt()
val resulty = (tempy - 32) / 1.8
tempConverted.setText(resulty.toString())
}
else{
Toast.makeText(this#MainActivity, "Select one conversion scale", Toast.LENGTH_SHORT).show()
}
}
}
}
You should check if etTemp.text.ToString() == "" (that is empty string) if it is, then do not try to convert it into int. The problem appears when you try to convert "null" value to int.
Inside the listener add a check for for EditText to check whether it is empty or not,
btnConverter.setOnClickListener {
// Add the validation check here ... like this -> if(etTemp.length() > 0){
val id = radioGroup.checkedRadioButtonId
val radioButton = findViewById<RadioButton>(id)
if (radioButton == findViewById(R.id.radioC)){
val temp =etTemp.text.toString().toInt()
val result = temp * 9/5 + 32
tempConverted.setText(result.toString())
}
else if (radioButton == findViewById(R.id.radioF)){
val tempy =etTemp.text.toString().toInt()
val resulty = (tempy - 32) / 1.8
tempConverted.setText(resulty.toString())
}
else{
Toast.makeText(this#MainActivity, "Select one conversion scale", Toast.LENGTH_SHORT).show()
}
// Close the check here -> }
else{
// Prompt the user to put some text in the field - this is called form validation before processing
// Toast.makeText(.....).show
}
}
check if the user has entered some input or not, one way is like below (Kotlin):
if(!etTemp.text.isNullOrEmpty())
{
temp =etTemp.text.toString().toInt()
}
Swift 4, iOS 11 - I have a UITextView that is pre-populated with text but I want users to be able to save any changes they make to the content there. I also have a Save button in the navigation bar and I would like to disable it until the user actually changes the text in the TextView.
I know how to test for empty but I don't know how to test for when the text has been edited. How do I modify the following to test for changes to the content of TextView?
#IBAction func textEditingChanged(_ sender: UITextView) {
updateSaveButtonState()
}
func updateSaveButtonState() {
let descriptionText = descriptionTextView.text ?? ""
saveButton.isEnabled = !descriptionText.isEmpty
}
We'll to use it a dynamic way and not only in single place, i tried to make it easier to implement around the whole app, subclassing the UITextView is one of the only ways we got here #holex has suggested isEdited boolean flag and it gave me an idea, Thanks to that.
Here is the steps to implement it:
First of all set the defaultText of the textView and set the target of the method that will be called when the textView will be edited, so you can customize what ever you want.
#IBOutlet weak var saveButton: UIBarButtonItem!
#IBOutlet weak var textView: SBTextView!{
didSet{
textView.defaultText = "Hello"
textView.setTarget = (selector:#selector(self.updateSaveButtonState),target:self)
}
}
Lets say you'll setup the saveButton in viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
// setup save button action
saveButton.action = #selector(saveAction(_:))
saveButton.target = self
self.updateSaveButtonState()
}
And last is your save action and the selector to update the view using isEdited flag.
//MARK:- Actions
#objc private func updateSaveButtonState(){
// has not been changed keep save button disabled
if self.textView.isEdited == false{
self.saveButton.isEnabled = false
self.saveButton.tintColor = .gray
}else {
// text has been changed enable save button
self.saveButton.isEnabled = true
self.saveButton.tintColor = nil // will reset the color to default
}
}
#objc private func saveAction(_ saveButton:UIBarButtonItem){
self.textView.updateDefaultText()
}
TextView Custom Class:
//
// SBTextView.swift
//
//
// Created by Saad Albasha on 11/17/17.
// Copyright © 2017 AaoIi. All rights reserved.
//
import UIKit
class SBTextView: UITextView,UITextViewDelegate {
var isEdited = false
private var selector : Selector?
private var target : UIViewController?
var setTarget: (selector:Selector?,target:UIViewController?) {
get{
return (selector,target)
}
set(newVal) {
selector = newVal.0
target = newVal.1
}
}
var textViewDefaultText = ""
var defaultText: String {
get {
return textViewDefaultText
}
set(newVal) {
textViewDefaultText = newVal
self.text = newVal
self.isEdited = false
}
}
//MARK:- Life Cycle
override init(frame: CGRect, textContainer: NSTextContainer?) {
super.init(frame: frame, textContainer: textContainer)
self.setupTextview()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.setupTextview()
}
private func setupTextview(){
// setup textview
self.text = textViewDefaultText
self.delegate = self
}
func updateDefaultText(){
self.defaultText = self.text!
// update save button state
target!.perform(self.selector, with: nil, with: nil)
}
//MARK:- Delegate
internal func textViewDidChange(_ textView: UITextView) {
if textViewDefaultText != textView.text! {
isEdited = true
}else {
isEdited = false
}
// update save button state
target!.perform(self.selector, with: nil, with: nil)
}
}
I hope this helps.