class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
getCurrentCountry()
}
private fun getCurrentCountry(){
val api = Retrofit.Builder().baseUrl(BASE_URL).addConverterFactory(GsonConverterFactory.create()).build().create(CountryReq::class.java)
GlobalScope.launch(Dispatchers.IO) {
val response = api.getCountries().awaitResponse()
if(response.isSuccessful){
val data = response.body()!!
withContext(Dispatchers.Main){
binding.selectCountry.text = "Demo text"
}
}
}
}
}
I'm trying to get data from an API and display it in a textview. But I can't seem to access the views or change its values from the GlobalScope.launch{} block.
Related
hi im currently using kotlin for my android project,as per instruction,i was told to make an apps that has recycleview to show list item and intent when you click on one of the list shown.
but i have this error when i want to run the app,the error was "No value passed for parameter 'ListUserAdapter'"
here is my code
ListUserAdapter.kt
class ListUserAdapter(private val ListUserAdapter: ArrayList<User>) : RecyclerView.Adapter<ListUserAdapter.ListViewHolder>() {
private lateinit var onItemClickCallBack: OnItemClickCallBack
fun setOnItemClickCallback(onItemClickCallback: OnItemClickCallBack) {
this.onItemClickCallBack = onItemClickCallback
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ListViewHolder {
val view: View = LayoutInflater.from(parent.context).inflate(R.layout.row_user, parent, false)
return ListViewHolder(view)
}
override fun onBindViewHolder(holder: ListViewHolder, position: Int) {
val (name, username) = ListUserAdapter[position]
holder.tvName.text = name
holder.tvUserName.text= username
holder.itemView.setOnClickListener {
onItemClickCallBack.onItemClicked(ListUserAdapter[holder.adapterPosition])
}
}
override fun getItemCount(): Int = ListUserAdapter.size
class ListViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
var tvName: TextView = itemView.findViewById(R.id.tv_username)
var tvUserName: TextView = itemView.findViewById(R.id.tv_name)
}
interface OnItemClickCallBack {
fun onItemClicked(data : User)
}
}
MainActivity.kt
class MainActivity : AppCompatActivity() {
private lateinit var adapter: ListUserAdapter
private lateinit var dataName: Array<String>
private lateinit var dataUsername: Array<String>
private lateinit var dataLocation: Array<String>
private lateinit var dataRepo: Array<String>
private lateinit var dataCompany: Array<String>
private lateinit var dataFollowers: Array<String>
private lateinit var dataFollowing: Array<String>
private lateinit var dataPhoto: TypedArray
private var users = arrayListOf<User>()
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setAdapter()
prepare()
addItem()
}
private fun setAdapter() {
adapter = ListUserAdapter() //error in here
with(binding) {
rvList.adapter = adapter
rvList.layoutManager =
GridLayoutManager(this#MainActivity, 2, GridLayoutManager.HORIZONTAL, false)
rvList.setHasFixedSize(true)
}
adapter.setOnItemClickCallback(object : ListUserAdapter.OnItemClickCallBack{
override fun onItemClicked(user: User) {
val intent = Intent(this#MainActivity, DetailActivity::class.java)
intent.putExtra(DetailActivity.KEY_USER, user)
startActivity(intent)
}
})
}
private fun prepare() {
dataName = resources.getStringArray(R.array.name)
dataUsername = resources.getStringArray(R.array.username)
dataPhoto = resources.obtainTypedArray(R.array.avatar)
dataLocation = resources.getStringArray(R.array.location)
dataRepo = resources.getStringArray(R.array.repository)
dataCompany = resources.getStringArray(R.array.company)
dataFollowers = resources.getStringArray(R.array.followers)
dataFollowing = resources.getStringArray(R.array.following)
}
private fun addItem() {
for (position in dataName.indices) {
val user = User(
dataUsername[position],
dataName[position],
dataLocation[position],
dataCompany[position],
dataRepo[position],
dataFollowers[position],
dataFollowing[position],
dataPhoto.getResourceId(position, -1)
)
users.add(user)
}
}
}
DetailActivity.kt
class DetailActivity : AppCompatActivity() {
private lateinit var binding: ActivityDetailBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityDetailBinding.inflate(layoutInflater)
setContentView(binding.root)
setData()
}
private fun setData() {
val dataUser = intent.getParcelableExtra<User>(KEY_USER) as User
with(binding) {
Glide.with(root)
.load(dataUser.photo)
.circleCrop()
.into(ivDetailAvatar)
}
}
companion object {
const val KEY_USER = "key_user"
}
}
just you need to replace adapter = ListUserAdapter() //error in here with adapter = ListUserAdapter(users) then your problem solve
You're just forgetting the constructor parameter :)
Your adapter class needs to receive a ArrayList of User to be instantiated, you already have it in your Activity, you just need to pass it as the constructor parameter :)
I would also rename the parameter name to something like users or usersList instead of `ListUserAdapter but because currently it is misleading, since this parameter is not an adapter, it is a list of users.
Just change the line with error to
adapter = ListUserAdapter(users)
But I think it is best for you to first call prepare() and addItem() and then instantiate your adapter. Or you can instantiate your adapter, but also create a addItems function, since it is a best practice for adapters.
fun addItems(users: List<User>) {
this.ListUserAdapter.addAll(users)
notifyDataSetChanged()
}
and use it after setting everything up inside onCreate doing something like
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setAdapter()
prepare()
addItem()
adapter.addItems(users)
}
but you could probably reorganize these methods to improve readability as well, but it will work :)
I am confused about how flow.collect works. Because in the lifecycleScope below I already say that a should be assigned by the value of data in my database. However, the value of a is still the string of "Hi" instead of "Hello".
class MainActivity : AppCompatActivity() {
private var binding: ActivityMainBinding? = null
private var a: String = "Hi"
override fun onCreate(savedInstanceState: Bundle?) {
binding = ActivityMainBinding.inflate(layoutInflater)
super.onCreate(savedInstanceState)
setContentView(binding?.root)
val somethingDao = SomethingDatabase.getDatabase(this).somethingDao()
lifecycleScope.launch {
somethingDao.insert(SomethingModel("Hello"))
somethingDao.fetchAllSomething().collect {
a = it[it.size - 1].name
}
}
println(a)
}
}
this is all of the information in my database
lifecycleScope.launch will start a coroutine, to make it simple the code inside lifecycleScope.launch will be executed in another thread and it will take some time until inserting data and reading it from database, but println(a) is on the main thread so it will be executed before this line a = it[it.size - 1].name, so your println(a) should be inside lifecycleScope.launch like this:
class MainActivity : AppCompatActivity() {
private var binding: ActivityMainBinding? = null
private var a: String = "Hi"
override fun onCreate(savedInstanceState: Bundle?) {
binding = ActivityMainBinding.inflate(layoutInflater)
super.onCreate(savedInstanceState)
setContentView(binding?.root)
val somethingDao = SomethingDatabase.getDatabase(this).somethingDao()
lifecycleScope.launch {
somethingDao.insert(SomethingModel("Hello"))
somethingDao.fetchAllSomething().collect {
a = it[it.size - 1].name
println(a)
}
}
}
}
Note: take a look on kotlin coroutines to better understand
https://www.mongodb.com/docs/realm/sdk/kotlin/realm-database/delete/delete-all-objects-of-a-type/
I am learning new kotlin-realm in my project. But i dont know how to delete objects. It keep showing error Caused by: io.realm.internal.interop.RealmCoreNotInATransactionException: [5]: Must be in a write transaction
this is the code :
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
private val realm by lazy { (application as CustomApplication).realm }
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
realm.writeBlocking {
copyToRealm(Buku(
name = "Perjuangan Menjual Baju"
))
copyToRealm(Buku(
name = "Perang Saudara"
))
}
val buku = realm.query<Buku>("name BEGINSWITH $0", "pera")
Log.i("AOEU", "buku = $buku")
CoroutineScope(Dispatchers.Main).launch {
val query = realm.query<Buku>().find()
realm.write {
delete(query)
}
}
}
}
After days of finding solution. I just realized that the only mistake in my code is
val query = realm.query().find()
Which is should be replaced with
val query = this.query().find()
This is what I want to achieve. And please help me with the regex for the third error.
You need to use isErrorEnabled and error atributes of your TextInputLayout instance.
const val PASSWORD_PATTERN = ...// your regex
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
binding.checkPasswordButton.setOnClickListener {
val password = binding.passwordEditText.text.toString()
val isPasswordValid =
Pattern.compile(PASSWORD_PATTERN).matcher(password).matches()
binding.passwordInputLayout.isErrorEnabled = !isPasswordValid
val passwordError = if (isPasswordValid) "" else
getString(R.string.invalid_password)
binding.passwordInputLayout.error = passwordError
}
}
}
I got error that mPresenter has not been initialized. I didn't understand WHY?
I got this error when I use Kotlin but if I use JAVA everything is fine
Here is my code
View
#StateStrategyType(value = AddToEndStrategy::class)
interface IHelloWorldView : MvpView {
fun showMessage(message: Int)
}
Presenter
#InjectViewState
class HelloWorldPresenter : MvpPresenter<IHelloWorldView>() {
fun show() = viewState.showMessage(R.string.message)
}
MainActivity
class MainActivity : MvpAppCompatActivity(), IHelloWorldView {
#InjectPresenter
lateinit var mPresenter: HelloWorldPresenter
lateinit var mText: TextView
lateinit var mButton: Button
override fun showMessage(message: Int) {
mText.setText(message)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
mText = findViewById(R.id.text)
mButton = findViewById(R.id.button)
mButton.setOnClickListener {
mPresenter.show()
}
}
}
Because you need to init it like in JAVA Foo foo = new Foo();
It seems like you only created a variable
class MainActivity : MvpAppCompatActivity(), IHelloWorldView {
#InjectPresenter
lateinit var mPresenter: HelloWorldPresenter
//initialisation
#ProvidePresenterTag(presenterClass = HelloWorldPresenter::class, type =PresenterType.GLOBAL)
fun providemPresenter() = HelloWorldPresenter()
fun mPresenter() = HelloWorldPresenter()
lateinit var mText: TextView
lateinit var mButton: Button
override fun showMessage(message: Int) {
mText.setText(message)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
mText = findViewById(R.id.text)
mButton = findViewById(R.id.button)
mButton.setOnClickListener {
mPresenter.show()
}
}
}
type = PresenterType.GLOBAL - do not exist (at least in kotlin)