My layout includes
<Spinner
android:id="#+id/spinnerCategory"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
app:layout_constraintBottom_toBottomOf="#+id/lblCategory"
app:layout_constraintStart_toEndOf="#+id/lblCategory"
app:layout_constraintTop_toTopOf="#+id/lblCategory" />
Strings.xml
<resources>
<string name="app_name">nearby</string>
<string-array name="categories">
<item>Any</item>
<item>Church</item>
<item>NT</item>
</string-array>
MainActivity.kt (only partially completed, so far)
package com.example.nearby
import android.os.Bundle
import android.widget.ArrayAdapter
import android.widget.Spinner
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.temp_layout.*
class MainActivity : AppCompatActivity() {
var mCategoryFilter = ""
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.temp_layout)
getInputs()
}
fun getInputs() {
if (!txtLat.toString().equals("")) {
var temp = txtLat.text.toString().toDouble()
mLatitude = temp.toFloat()
}
if (!txtLong.toString().equals("")) {
mLongitude = txtLong.text.toString().toFloat()
}
val spinner: Spinner = findViewById(R.id.spinnerCategory)
val adapter = ArrayAdapter.createFromResource(
this,
R.array.categories, R.layout.simple_spinner_item
)
adapter.setDropDownViewResource(R.layout.simple_spinner_dropdown_item)
spinner.adapter = adapter
}
}
Android Studio marks the following as "unresolved references"
the word "array" in R.array.categories
"simple_spinner_item"
"simple_spinner_dropdown_item"
How do I resolve these references?
Solution
Mike M's suggestion that I use the Invalidate Caches/Restart option seems to have solved the reference to "array".
The simple_spinner layout references need to be prefixed with android (with lower case a), as in android.R.layout.simple_spinner_item.
Beware, if using Android Studio's automatic conversion of Java code to Kotlin. It seems to have been this that deleted "android" from the layout references.
Related
I’m using Android Studio with Kotlin. I’d like to be able to drag and drop items in a ListView to reorder them. I also want to swipe left to delete. This was pretty straightforward in XCode/Swift for iOS, but I’m having trouble finding examples for Android/Kotlin. I’ve seen some fairly old discussions with Java and with RecyclerView, but it would be great to be able to do it in Kotlin with ListView. I should add that the ListView does everything I need so far – I realise there is much discussion about ListView vs RecyclerView.
I’m not asking for people to solve this for me, but it would be great if you could point me to anything that might get me going.
By way of background, here is my code. It is just a ListView with numbers ‘zero’ to ‘ten’ and the selected row highlighted. I should add that I wrote this code with the help of many discussions here and on YouTube, for which I’m very grateful.
I also have a ListView with sections that needs these options, but I’ve not put the code here for that (happy to do so if required).
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ListView
android:id="#+id/list_view"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:layout_margin="16dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
listview_row.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/rowText"
android:layout_width="match_parent"
android:layout_height="48dp"
android:textColor="#color/black"
android:paddingLeft="0dp"
android:paddingTop="8dp"
android:paddingRight="0dp"
android:paddingBottom="8dp"
android:autoSizeTextType="uniform"
android:autoSizeMaxTextSize="40sp"
android:autoSizeMinTextSize="8sp"
android:autoSizeStepGranularity="2sp"
android:lines="1" />
</LinearLayout>
listview_selected_row.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/selectedRowText"
android:layout_width="match_parent"
android:layout_height="48dp"
android:paddingLeft="0dp"
android:paddingRight="0dp"
android:paddingTop="8dp"
android:paddingBottom="8dp"
android:background="#color/teal_200"
android:textColor="#color/black"
android:autoSizeTextType="uniform"
android:autoSizeMaxTextSize="40sp"
android:autoSizeMinTextSize="8sp"
android:autoSizeStepGranularity="2sp"
android:lines="1" />
</LinearLayout>
ListViewAdapter.kt
package com.ijmusic.listviewrearrange
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.TextView
val TYPE_LISTVIEW_ITEM = 0
val TYPE_LISTVIEW_SELECTED_ITEM = 1
class ListViewAdapter(private val context: Context): BaseAdapter() {
private val mData: ArrayList<String> = ArrayList()
private var mIndex: ArrayList<Int> = ArrayList()
private var mSelectedItem = -1
private lateinit var textView: TextView
fun addItem(item: String, index: Int) {
mData.add(item)
mIndex.add(index)
notifyDataSetChanged()
}
fun addSelectedItem(item: String, index: Int) {
mData.add(item)
mIndex.add(index)
mSelectedItem = mData.size - 1
notifyDataSetChanged()
}
fun highlightSelection(int: Int) {
mSelectedItem = int
notifyDataSetChanged()
}
override fun getItemViewType(position: Int): Int {
return if (position == mSelectedItem) TYPE_LISTVIEW_SELECTED_ITEM
else TYPE_LISTVIEW_ITEM
}
override fun getCount(): Int {
return mData.size
}
override fun getItem(position: Int): Any {
return mData[position]
}
override fun getItemId(position: Int): Long {
return position.toLong()
}
override fun getView(position: Int, view: View?, parent: ViewGroup?): View? {
var view = view
var type = getItemViewType(position)
if (position == mSelectedItem) type = TYPE_LISTVIEW_SELECTED_ITEM
when (type) {
TYPE_LISTVIEW_ITEM -> {
view = LayoutInflater.from(context).inflate(R.layout.listview_row, parent, false)
textView = view.findViewById(R.id.rowText)
}
TYPE_LISTVIEW_SELECTED_ITEM -> {
view = LayoutInflater.from(context).inflate(R.layout.listview_selected_row, parent, false)
textView = view.findViewById(R.id.selectedRowText)
}
}
textView.text = mData[position]
return view
}
}
MainActivity.kt
package com.ijmusic.listviewrearrange
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.AdapterView
import com.ijmusic.listviewrearrange.databinding.ActivityMainBinding
val list = listOf("zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten")
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
private lateinit var mAdapter: ListViewAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
mAdapter = ListViewAdapter(this)
setListView()
binding.listView.onItemClickListener = object: AdapterView.OnItemClickListener {
override fun onItemClick(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
binding.listView.setSelection(position)
mAdapter.highlightSelection(position)
}
}
}
fun setListView() {
for ( i in 0 until list.count() ) {
if ( i == 0 )
mAdapter.addSelectedItem(list[i], i)
else
mAdapter!!.addItem(list[i], i)
}
binding.listView.adapter = mAdapter
}
}
You can look into a concept called gestures in android Kotlin. It will help.
I have made a basic shopping list app that utilises a recyclerview to display the list items. I am trying to add a settings screen using navigation with fragments. I am running into the issue where my recyclerview & data display when I open the app, however when I go to the settings menu then back to the main screen there's no recyclerview. Logcat shows the error "W/RecyclerView: No adapter attached; skipping layout"
MainActivity.kt
package com.example.shoppinglist
import android.app.Dialog
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.Toast
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import androidx.navigation.findNavController
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.floatingactionbutton.FloatingActionButton
class MainActivity : AppCompatActivity(), RVAdapter.ListItemClickInterface {
lateinit var itemsRV: RecyclerView
lateinit var addFAB: FloatingActionButton
lateinit var list: List<ListItems>
lateinit var RVAdapter: RVAdapter
lateinit var viewModel: ViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setupActionBarWithNavController(findNavController(R.id.fragment_main))
itemsRV = findViewById(R.id.recyclerView)
addFAB = findViewById(R.id.idFABAdd)
list = ArrayList<ListItems>()
RVAdapter = RVAdapter(list, this)
itemsRV.layoutManager = LinearLayoutManager(this)
itemsRV.adapter = RVAdapter
val repository = Repository(Database(this))
val factory = ViewModelFactory(repository)
viewModel = ViewModelProvider(this, factory).get(ViewModel::class.java)
viewModel.getAllListItems().observe(this, Observer {
RVAdapter.list = it
RVAdapter.notifyDataSetChanged()
})
addFAB.setOnClickListener {
openDialog()
}
}
override fun onSupportNavigateUp(): Boolean {
val navController = findNavController(R.id.fragment_main)
return navController.navigateUp() || super.onSupportNavigateUp()
}
fun openDialog() {
val dialog = Dialog(this)
dialog.setContentView(R.layout.add_dialog)
val cancelButton = dialog.findViewById<Button>(R.id.idBtnCancel)
val addButton = dialog.findViewById<Button>(R.id.idBtnAdd)
val itemEdt = dialog.findViewById<EditText>(R.id.idEditItemName)
val itemQuantityEdt = dialog.findViewById<EditText>(R.id.idEditItemQuantity)
cancelButton.setOnClickListener {
dialog.dismiss()
}
addButton.setOnClickListener {
val itemName: String = itemEdt.text.toString()
val itemQuantity: String = itemQuantityEdt.text.toString()
if (itemName.isNotBlank() && itemQuantity.isNotBlank()) {
val items = ListItems(itemName, itemQuantity)
viewModel.insert(items)
Toast.makeText(applicationContext, "Item Added", Toast.LENGTH_SHORT).show()
RVAdapter.notifyDataSetChanged()
dialog.dismiss()
} else {
Toast.makeText(applicationContext, "Enter All Info To Add Item",
Toast.LENGTH_SHORT)
.show()
}
}
dialog.show()
}
override fun onItemClick(listItems: ListItems) {
viewModel.delete(listItems)
RVAdapter.notifyDataSetChanged()
Toast.makeText(applicationContext, "Item Deleted", Toast.LENGTH_SHORT).show()
}
}
HomeFragment.kt
package com.example.shoppinglist
import android.os.Build
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.annotation.RequiresApi
import androidx.navigation.fragment.findNavController
import androidx.preference.PreferenceManager
import kotlinx.android.synthetic.main.fragment_home.*
class HomeFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_home, container, false)
}
#RequiresApi(Build.VERSION_CODES.N)
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
idFABSettings.setOnClickListener {
findNavController().navigate(R.id.action_homeFragment_to_settingsFragment)
}
loadSettings()
}
#RequiresApi(Build.VERSION_CODES.N)
private fun loadSettings(){
val sp = PreferenceManager.getDefaultSharedPreferences(context)
val theme = sp.getBoolean("theme_switch",false)
}
}
SettingsFragment.kt
package com.example.shoppinglist
import android.os.Bundle
import androidx.preference.PreferenceFragmentCompat
class SettingsFragment : PreferenceFragmentCompat() {
override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
setPreferencesFromResource(R.xml.root_preferences, rootKey)
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<fragment
android:id="#+id/fragment_main"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="#navigation/navigation"
/>
</RelativeLayout>
fragment_home.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:background="?attr/colorPrimary"
tools:context=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:listitem="#layout/list_rv_item"/>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/idFABAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_alignParentBottom="true"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="20dp"
android:backgroundTint="?attr/colorSecondary"
android:contentDescription="Add Item Button"
android:src="#drawable/ic_add"
android:tint="#android:color/white" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/idFABSettings"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentBottom="true"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="20dp"
android:backgroundTint="?attr/colorSecondary"
android:contentDescription="Add Item Button"
android:src="#drawable/ic_settings"
android:tint="#android:color/white" />
</RelativeLayout>
navigation.xml
<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/navigation"
app:startDestination="#id/homeFragment">
<fragment
android:id="#+id/settingsFragment"
android:name="com.example.shoppinglist.SettingsFragment"
android:label="Settings" >
<action
android:id="#+id/action_settingsFragment_to_homeFragment"
app:destination="#id/homeFragment" />
</fragment>
<fragment
android:id="#+id/homeFragment"
android:name="com.example.shoppinglist.HomeFragment"
android:label="Shopping List"
tools:layout="#layout/fragment_home" >
<action
android:id="#+id/action_homeFragment_to_settingsFragment"
app:destination="#id/settingsFragment" />
</fragment>
</navigation>
Not sure if any more info is required. Apologies in advance - I am new to android studio & kotlin.
You are trying to work with views that are specific to HomeFragment's layout through the MainActivity. This will not work correctly. The first time you start the activity, in onCreate you use findViewById to find the view with ID recyclerView, and it successfully finds it because at that time the view is part of the HomeFragment, which is in the layout.
However, when you change fragments, the original fragment view is detached and removed. When you return to the first fragment, Android creates a new instance of your HomeFragment and its layout. The MainActivity is still referencing the original RecyclerView from the first instance of the HomeFragment, so it will update that view that is no longer on screen and it won't touch the new view. You have actually created a memory leak where the MainActivity is preventing that first fragment's view from being destroyed.
Another issue that you haven't discovered yet possibly is that if you rotate the screen while the SettingsFragment is open, you'll crash with a NullPointerException. This is because a screen rotation will cause a new Activity to be created, so onCreate() will be called again, and when it tries to find recyclerView when the HomeFragment is not in the layout, it will fail.
It doesn't make sense to work with a Fragment's specific views from the hosting Activity. The Activity should not have to know any details about what is in a Fragment and what to do with the contents of that fragment. All your code that has to do with the RecyclerView should be in HomeFragment.
this is the XML which seems okay
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/iam_a_rider"
android:id= "#+id/rider"/>
//this the XML code for the button I created that I would like to declare in the main activity page
this is the code I was trying to execute but was not successful since it keeps bring an error of val not recognised with in the code
main activity kt
class MainActivity : AppCompatActivity()
{
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val rider: Button = findViewById<Button>(R.id.rider)
rider.setOnClickListener()
// still brings an error of rider not in use or doesn't recognise it at all
}
I have created a To do List app with a Floating Actin Button and my code is returning three errors:
Expecting ')'
Expecting an Element
Unresolved Reference fab
The code was fine until I decided to add another button to the bottom of my activity_main.xml file and needed to add a relativelayout inside a coordinator layout to do it. The new button is to allow users to change the colour of the background. Once adding this code into the MainActivity.kt file the original findViewById code for the fab no longer works and gives the above errors.
MainActivity.kt file
abstract class MainActivity : AppCompatActivity() ,UpdateAndDelete {
private lateinit var database: DatabaseReference
var toDoList: MutableList<ToDoModel>? = null
lateinit var adapter: ToDoAdapter
private var listViewItem : ListView?=null
internal abstract var screenView:View
internal abstract var clickMe:Button
internal abstract var color:Array<Int>
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
intArrayOf(Color.MAGENTA, Color.YELLOW, Color.BLUE, Color.BLACK)
screenView = findViewById(R.id.rView)
clickMe = findViewById(R.id.colorButton) as Button
clickMe.setOnClickListener(object:View.OnClickListener {
override fun onClick(view: View) {
val aryLength = color.size
val random = Random
val rNum = random.nextInt(aryLength)
screenView.setBackgroundColor(color[rNum])
}
}
val fab: View = findViewById(R.id.fab)
listViewItem = findViewById<ListView>(R.id.item_listView)
database = FirebaseDatabase.getInstance().reference
fab.setOnClickListener { view ->
val alertDialog = AlertDialog.Builder(this)
val textEditText = EditText (this)
alertDialog.setMessage("Add TODO Item")
alertDialog.setTitle("Enter TO DO Item")
alertDialog.setView(textEditText)
alertDialog.setPositiveButton("Add") {dialog, i ->
val todoItemData = ToDoModel.createList()
todoItemData.itemDataText = textEditText.text.toString()
todoItemData.done = false
val newItemData=database.child("todo").push()
todoItemData.UID = newItemData.key
newItemData.setValue(todoItemData)
dialog.dismiss()
Toast.makeText(this, "item saved", Toast.LENGTH_LONG).show()
}
alertDialog.show()
}
activity_main.xml file
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
tools:context=".MainActivity">
<ListView
android:id="#+id/item_listView"
android:layout_width="match_parent"
android:layout_height="651dp"
android:background="#color/white"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:scrollbars="none" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="15dp"
android:layout_gravity="bottom|end"
android:elevation="6dp"
app:pressedTranslationZ="12dp"
android:src="#drawable/ic_baseline_add_24" />
<RelativeLayout
android:id="#+id/rView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="bottom"
android:gravity="bottom">
<Button
android:id="#+id/colorButton"
android:layout_width="170dp"
android:layout_height="58dp"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
android:layout_marginStart="22dp"
android:layout_marginBottom="11dp"
android:backgroundTint="#color/teal_200"
android:text="Change Colour"
android:textColor="#color/black" />
</RelativeLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
Looking at this bit of your code:
clickMe.setOnClickListener(object:View.OnClickListener {
override fun onClick(view: View) {
val aryLength = color.size
val random = Random
val rNum = random.nextInt(aryLength)
screenView.setBackgroundColor(color[rNum])
}
}
val fab: View = findViewById(R.id.fab)
You are getting the first error because you are not properly closing the call to clickMe.setOnClickListener by providing a ) after the } on the second to last line. The compiler realizes this on the last line that defines fab, and so it is that line that the compiler is actually complaining about.
To fix this, add a ) to the second to last line, like this:
clickMe.setOnClickListener(object:View.OnClickListener {
override fun onClick(view: View) {
val aryLength = color.size
val random = Random
val rNum = random.nextInt(aryLength)
screenView.setBackgroundColor(color[rNum])
}
})
val fab: View = findViewById(R.id.fab)
Once you have an initial syntax error, it doesn't really matter what other errors the compiler is producing. Fix this first error and re-evaluate where you're at.
If the code you supply is supposed to be complete...that is, the entire contents of the file MainActivity.kt is provided, then you are missing a number of closing curlies (}) at the end of the code.
I have a simple android project where I'm populating a list of items in a database. To do this I'm using RecyclerView showing in my activity_main.xml
These are my two (and only two that exist) xml files
activity_main.xml
package com.twocrows.foretoldapp;
import androidx.appcompat.app.AppCompatActivity;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import com.twocrows.foretoldapp.adapter.ChartAdapter;
import com.twocrows.foretoldapp.entity.Chart;
import com.twocrows.foretoldapp.viewmodel.ChartViewModel;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private ChartViewModel chartViewModel;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setHasFixedSize(true);
final ChartAdapter adapter = new ChartAdapter();
recyclerView.setAdapter(adapter);
chartViewModel = new ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory.getInstance(this.getApplication())).get(ChartViewModel.class);
chartViewModel.getAllCharts().observe(this, new Observer<List<Chart>>() {
#Override
public void onChanged(List<Chart> charts) {
adapter.setCharts(charts);
}
});
}
}
which shows in the preview like this
chart_item.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="8dp">
<TextView
android:id="#+id/text_view_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:text="location"
android:textAppearance="#style/TextAppearance.AppCompat.Medium" />
<TextView
android:id="#+id/text_view_name"
android:layout_width="139dp"
android:layout_height="38dp"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_marginEnd="248dp"
android:layout_marginRight="248dp"
android:layout_below="#+id/text_view_name"
android:text="Chart Name"
android:textAppearance="#style/TextAppearance.AppCompat.Large"
tools:ignore="NotSibling" />
<TextView
android:id="#+id/text_view_dateTime"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/text_view_name"
android:text="MM/DD/YYYY"/>
</RelativeLayout>
</androidx.cardview.widget.CardView>
MainActivity.java
package com.twocrows.foretoldapp;
import androidx.appcompat.app.AppCompatActivity;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import com.twocrows.foretoldapp.adapter.ChartAdapter;
import com.twocrows.foretoldapp.entity.Chart;
import com.twocrows.foretoldapp.viewmodel.ChartViewModel;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private ChartViewModel chartViewModel;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setHasFixedSize(true);
final ChartAdapter adapter = new ChartAdapter();
recyclerView.setAdapter(adapter);
chartViewModel = new ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory.getInstance(this.getApplication())).get(ChartViewModel.class);
chartViewModel.getAllCharts().observe(this, new Observer<List<Chart>>() {
#Override
public void onChanged(List<Chart> charts) {
adapter.setCharts(charts);
}
});
}
}
The issue is that whenever I try to run the app, it's showing me an old version of the main activity xml file. I no longer even have these components in the xml so I don't understand where they are coming from.
#Things I've tried
Invalidate cache/ restart
clean build
edit configuration, uncheck 'skip installation if apk has not changed'
Nothing so far has worked. Any help would be appreciated. Thanks!
The issue of your app showing an old version of the activity_main.xml, even though you no longer have those components in the file, may be due to having two different layout resource files for a single activity.
You can check your layout resource directory to see if you have two different versions of the main activity layout file, such as "main.xml" and "main.xml(v21)", which may be causing the confusion. You can see the reason for having multiple files in this answer.
In this case, the solution would be to make sure that you're editing the correct layout file. If you edited an XML file but your emulator is running the v21 file, you can copy your code and paste it into the other file.
If you've made changes to the correct file but are still seeing the old version in the emulator, you can try cleaning and rebuilding the project, or even deleting the app from the emulator and reinstalling it.
If you continue to experience the issue, you may also want to check the AndroidManifest.xml file to ensure that the correct layout file is being used for the main activity. This file can be found in the "app" directory of your project.