Pass Date from Datepicker to Spinner selected item and load API Response in Fragment

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• different between call view by name or use binding in android

  i'am a newest in android kotlin

  I want to know what is the difference between the two lines of code below and which one is better to use

  class MainActivity : AppCompatActivity() {
  private lateinit var binding: ActivityMaindinding
  
  override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      bindins = DataBindingutil.setContentview( this, R.layout.activity_main)
  
  
          textview.text="text"//or
  
          binding.textview.text="text"
  }}
  
• Get multiple times current time on single Button

  I have a button showing text START when I click on it I shows me current time in textview.(I consider this time as start time). Than convert the text on Button into STOP. When I click on it again show me current time on another textview(I consider this time as stop time). And then calculate the difference between these two time. I want this same working for multiple time. I means First button show Text ENTER. When I click on it it should show current time in textview.(I will consider this time as Enter time). Than convert the text on Button into START. When I click on it again show me current time on another textview(I will consider this time as start time). Than convert the text on Button into STOP. When I click on it again show me current time on another textview(I will consider this time as STOP time). And last Than convert the text on Button into EXIT. When I click on it again show me current time on another textview(I will consider this time as Exit time).

  Here is my code:

   btn_start.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
  
                  if (isStarted){
                      Calendar calendar = Calendar.getInstance();
                      SimpleDateFormat format = new SimpleDateFormat("hh:mm:ss aa");
                      String time = format.format(calendar.getTime());
  
  
                      tvend.setText(time);
                      try {
                          Date date1 = format.parse(tvend.getText().toString());
                          Date date2 = format.parse(tvstarttime.getText().toString());
                          long mills = date1.getTime() - date2.getTime();
                          Log.v("Data1", ""+date1.getTime());
                          Log.v("Data2", ""+date2.getTime());
                          int hours = (int) (mills/(1000 * 60 * 60));
                          int mins = (int) (mills % (1000*60*60));
  
                          String diff = hours + ":" + mins;
                          diffence.setText(diff);
                      } catch (ParseException e) {
                          e.printStackTrace();
                      }
                      btn_start.setText("START");
                  }else {
                      Calendar calendar = Calendar.getInstance();
                      SimpleDateFormat format = new SimpleDateFormat("hh:mm:ss aa");
                      String time1 = format.format(calendar.getTime());
  
  
                      tvstarttime.setText(time1);
                      btn_start.setText("STOP");
                  }
                  isStarted = !isStarted;
  
  
  
              }
          });
  
  
  
  
• android emulator disable microphone when launching device

  How do we disable the (virtual) microphone when launching the emulator?

  Situation
  When launching an Android Studio stock emulator device, the microphone is always enabled and listening.

  Why would we want this fix

  • Convenience, Many users have a microphone headset and when the microphone is enabled, they lose noise canceling and/or stereo. It can be extremely annoying, forcing the user to disconnect the device which swaps the emulator audio + sounds to another microphone/speaker input/output.
  • Security risk, the microphone is actively listening. Is the data going anywhere? Who knows...this is an unnecessary security risk for any organization, IE a dev is on a (zoom, teams, meetings) call with an open emulator that is using the microphone and listening).

  Possible Solutions (based on practicality)

  1. flag to disable virtual audio devices (IE the mac's speaker or attached headphones w/ a microphone). I've seen 0 documentation regarding a flag like this.
  2. flag to provide to the emulator to disable all audio input (see answer 1). TLDR add the flag -no-audio
  3. route the android studio emulator (or the mac's microphone audio input) to a virtual device that is not listening. Or have the default OS microphone input set to 0 volume. This can be done via macOSX Automator
  4. route the adb emulator to the mac's internal microphone instead of the current microphone to avoid it triggering the headsets microphone settings.

  The preferred solution

  • Microphone audio-in is disabled when booting the emulator
  • Android device audio-out remains and uses the computer's default speakers
  • The computer's default microphone is not triggered (at all) to avoid causing a stereo -> mono swap or noise cancellation breakage.

  System Information:

  • android emulator: 31.2.10.0
  • MacOS 12.3.1
  • Headsets tested with these issues:
    • Bose NC 700
    • Bose QC series
    • Sony WF-1000XM4
    • Sony WH-1000XM3
    • any headset with a microphone connection macro that does something with the speaker (like talk through) or with the input audio like stereo -> mono.
• How do I resolve InflateException: Binary XML file line problem?

  I'm going to inflate the recycler view in the home fragment using the Navigation component. There are two problems here.

  1. InflateException Issues
  2. Only one first index appears in view in ArrayList

  here is error message.

  Caused by: android.view.InflateException: Binary XML file line #11 in kr.hnu.project:layout/activity_navigation: Binary XML file line #10 in kr.hnu.project:layout/content_navigation: Error inflating class fragment
   Caused by: android.view.InflateException: Binary XML file line #10 in kr.hnu.project:layout/content_navigation: Error inflating class fragment
   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void kr.hnu.project.MyRecyclerAdapter.notifyDataSetChanged()' on a null object reference
      at kr.hnu.project.ui.home.HomeFragment.init(HomeFragment.java:81)
      at kr.hnu.project.ui.home.HomeFragment.onCreateView(HomeFragment.java:55)
  

  And this is my code.

  homefragment.java:

  public class HomeFragment extends Fragment {
  private final static String setMsg = "SELECT sender, receiver, title, date FROM MessageDB";
  DBHelper dbHelper;
  SQLiteDatabase readDB;
  Cursor cursor;
  ArrayList<MyItem> mailItem;
  MyRecyclerAdapter myAdapter;
  String curUser;
  
  private FragmentHomeBinding binding;
  
  public View onCreateView(@NonNull LayoutInflater inflater,
                           ViewGroup container, Bundle savedInstanceState) {
      HomeViewModel homeViewModel =
              new ViewModelProvider(this).get(HomeViewModel.class);
  
      binding = FragmentHomeBinding.inflate(inflater, container, false);
      View root = binding.getRoot();
      ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_home, container, false);
  
      NavigationActivity main = (NavigationActivity) getActivity();
      curUser = main.getCurrentUserID();
  
      dbHelper = new DBHelper(inflater.getContext());
      readDB = dbHelper.getReadableDatabase();
      mailItem = new ArrayList<MyItem>();
  
      init();
  
      myAdapter = new MyRecyclerAdapter(mailItem);
      LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
      binding.recyclerview.setLayoutManager(layoutManager); // 앞에 binding!!!
      binding.recyclerview.setAdapter(myAdapter);
  
      return root;
  }
  
  public void init() {
      cursor = readDB.rawQuery(setMsg, null);
      mailItem.clear();
  
      while (cursor.moveToNext()) {
  
          if (curUser.equals(cursor.getString(cursor.getColumnIndexOrThrow("receiver")))) {
              mailItem.add(new MyItem(cursor.getString(cursor.getColumnIndexOrThrow("sender")),
                      cursor.getString(cursor.getColumnIndexOrThrow("title")), cursor.getString(cursor.getColumnIndexOrThrow("date"))
              ));
  
          }
          cursor.close();
          myAdapter.notifyDataSetChanged();
      }
  }
  

  fragment_home.xml:

  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@+id/linear"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  tools:context=".ui.home.HomeFragment">
  
  <androidx.recyclerview.widget.RecyclerView
      android:id="@+id/recyclerview"
      android:layout_width="match_parent"
      android:layout_height="match_parent"/>
  

  activity_navigation.xml:

  <androidx.drawerlayout.widget.DrawerLayout 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/drawer_layout"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"
  tools:openDrawer="start">
  
  <include
      android:id="@+id/app_bar_navigation"
      layout="@layout/app_bar_navigation"
      android:layout_width="match_parent"
      android:layout_height="match_parent" />
  
  <com.google.android.material.navigation.NavigationView
      android:id="@+id/nav_view"
      android:layout_width="wrap_content"
      android:layout_height="match_parent"
      android:layout_gravity="start"
      android:fitsSystemWindows="true"
      app:headerLayout="@layout/nav_header_navigation"
      app:menu="@menu/activity_navigation_drawer" />
  

  </androidx.drawerlayout.widget.DrawerLayout>

  content_navigation.xml:

  <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"
  app:layout_behavior="@string/appbar_scrolling_view_behavior"
  tools:showIn="@layout/app_bar_navigation">
  
  <fragment
      android:id="@+id/nav_host_fragment_content_navigation"
      android:name="androidx.navigation.fragment.NavHostFragment"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:defaultNavHost="true"
      app:layout_constraintHorizontal_bias="0.0"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toTopOf="parent"
      app:navGraph="@navigation/mobile_navigation" />
      </androidx.constraintlayout.widget.ConstraintLayout>
  
• Android APP crashes while Loading the ads

  I am trying to make a social media application. I am trying to insert ads in between the posts. In the below code when running app crashes while executing the adaptor. i have added the adaptor code. sorry for the big code. when i comment the ads and run, post is coming properly. problem is when i include the ad code app crashes without any error. sometimes its running continuously.

  class NewpostAdapter(
      val context: Context,
      val Post: ArrayList<Newpost>): RecyclerView.Adapter<RecyclerView.ViewHolder>()
  {
      private var firebaseUser:FirebaseUser? =null
  
      companion object{
          //TAG
          private const val TAG ="PRODUCT_TAG"
  
          //there will be 2 view type 1 for the actual content and 2 for the native ad
  
          private const val VIEW_TYPE_CONTENT =0
          private const val VIEW_TYPE_AD=1
  
  
      }
  
  
  
  override fun onCreateViewHolder(parent: ViewGroup, viewType: Int):RecyclerView.ViewHolder
  {
  
      val view :View
  
  
  
        if (viewType == VIEW_TYPE_CONTENT){
          view = LayoutInflater.from(context).inflate(R.layout.new_post,parent,false)
            return HolderProduct(view)
        }
  
        else{
            //inflate/return row_native_ad.xml
            view = LayoutInflater.from(context).inflate(R.layout.row_native_ad,parent,false)
           return HolderNativeAd(view)
  
        }
  
  
  }
  
  
  
  override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
    firebaseUser = FirebaseAuth.getInstance().currentUser
  
  
  
  
        if (getItemViewType(position)== VIEW_TYPE_CONTENT) {
  
             val post = Post[position]
  
              val holderProduct =holder as HolderProduct
  
              Picasso.get().load(post.getPostimage()).into(holderProduct.postImage)
  
              publisherInfo(
                  holderProduct.profileImage,
                  holderProduct.userName,
                  holderProduct.publisheruser,
                      post.getPublisher()
              )
  
  
  
  
  
          }
  
             if (getItemViewType(position)== VIEW_TYPE_AD) {
  
  
              val adLoader  = AdLoader.Builder(context ,context.getString(R.string.native_ad_id_test))
                  .forNativeAd { nativeAd ->
                      Log.d(TAG, "onNativeAdLoaded: ")
  
                      //Ad is loaded,show it
  
                      //instance of our HolderNativeAd to access UI views of row_Native_ad.xml
                      val holderNativeAd = holder as HolderNativeAd
                      displayNativeAd(holderNativeAd,nativeAd)
                  }
                  .withAdListener(object : AdListener() {
  
                      override fun onAdClicked() {
                          super.onAdClicked()
                          Log.d(TAG, "onAdClicked: ")
                      }
  
                      override fun onAdClosed() {
                          super.onAdClosed()
                          Log.d(TAG, "onAdClosed: ")
                      }
  })
                  .withNativeAdOptions(NativeAdOptions.Builder().build()).build()
  
              adLoader.loadAd(AdRequest.Builder().build())
  
          }
  
  
      }
   private fun displayNativeAd(holderNativeAd: NewpostAdapter.HolderNativeAd, nativeAd: NativeAd) {
          /*------Get Ad assets from the NativeAd Object-----*/
  
          val headLine = nativeAd.headline
          val body  = nativeAd.body
          val callToAction = nativeAd.callToAction
          val icon = nativeAd.icon
          val price = nativeAd.price
          val store = nativeAd.store
          val starRating = nativeAd.starRating
          val advertiser = nativeAd.advertiser
          val mediaContent = nativeAd.mediaContent
  
          /*-----Same assets aren't guaranteed to be in every nativeAd,so we need to check before displaying item-----*/
  
          if (headLine==null){
              //no content ,hide view
              holderNativeAd.ad_headline.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_headline.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_headline.text=headLine
  
          }
  
          if (body==null){
              //no content ,hide view
              holderNativeAd.ad_body.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_body.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_body.text=body
  
          }
  
  
          if (icon == null){
              //no content ,hide view
              holderNativeAd.ad_app_icon.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_app_icon.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_app_icon.setImageDrawable(icon.drawable)
  
          }
          if (starRating == null){
              //no content ,hide view
              holderNativeAd.ad_stars.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_stars.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_stars.rating=starRating.toFloat()
  
          }
          if (price==null){
              //no content ,hide view
              holderNativeAd.ad_price.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_price.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_price.text=price
  
          }
          if (store==null){
              //no content ,hide view
              holderNativeAd.ad_store.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_store.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_store.text=store
  
          }
          if (advertiser==null){
              //no content ,hide view
              holderNativeAd.ad_advertiser.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_advertiser.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_advertiser.text=advertiser
  
          }
          if (mediaContent==null){
              //no content ,hide view
              holderNativeAd.media_view.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.media_view.visibility= View.VISIBLE
              // set data
              holderNativeAd.media_view.setImageScaleType(ImageView.ScaleType.CENTER_CROP)
              holderNativeAd.media_view.setMediaContent(mediaContent)
  
          }
          if (callToAction==null){
              //no content ,hide view
              holderNativeAd.ad_call_to_action.visibility = View.INVISIBLE
          }
          else{
              //have content ,show view
              holderNativeAd.ad_call_to_action.visibility= View.VISIBLE
              // set data
              holderNativeAd.ad_call_to_action.text=callToAction
              //handle ad button click
              holderNativeAd.native_Ad_View.callToActionView=holderNativeAd.ad_call_to_action
  
          }
          // add nativeAd  the NativeView
          holderNativeAd.native_Ad_View.setNativeAd(nativeAd)
      }
  
  
      override fun getItemCount(): Int {
      return  Post.size
  }
  
     override fun getItemViewType(position: Int): Int {
          //logic to display Native Ad between content
          if (position % 5 == 0){
              //after 5 items .show native ad
              return VIEW_TYPE_CONTENT
          }
          else{
              //return the view type VIEW_TYPE_CONTENT to show content
              return  VIEW_TYPE_AD
          }
  
      }
  
  
  
      inner class HolderProduct( itemView: View): RecyclerView.ViewHolder(itemView) {
  
  
         val profileImage: CircleImageView
         val postImage: ImageView
         val likeButton: ImageView
         val commentButton: ImageView
         val saveButton: ImageView
         val userName: TextView
        val likesuser: TextView
         val publisheruser: TextView
         val descriptionuser: TextView
         val commentsuser: TextView
  
         init {
             profileImage = itemView.findViewById(R.id.user_profile_image_newPost)
             postImage = itemView.findViewById(R.id.post_image_home2)
             likeButton = itemView.findViewById(R.id.post_image_like_button)
             commentButton = itemView.findViewById(R.id.post_image_comment_button)
             saveButton = itemView.findViewById(R.id.post_save_comment_button)
             userName = itemView.findViewById(R.id.user_name_search)
             likesuser = itemView.findViewById(R.id.likes_user)
             publisheruser = itemView.findViewById(R.id.publisher_user)
             descriptionuser = itemView.findViewById(R.id.description_user)
             commentsuser = itemView.findViewById(R.id.comments_user)
         }
  
  
     }
      //ViewHolder class for row_native_ad.xml
  
      inner class HolderNativeAd(itemView: View): RecyclerView.ViewHolder(itemView){
          //init UI Views
          val ad_app_icon :ImageView =itemView.findViewById(R.id.ad_app_icon)
          val ad_headline:TextView=itemView.findViewById(R.id.ad_headline)
          val ad_advertiser:TextView=itemView.findViewById(R.id.ad_advertiser)
          val ad_stars: RatingBar =itemView.findViewById(R.id.ad_stars)
          val ad_body:TextView=itemView.findViewById(R.id.ad_body)
          val media_view: MediaView =itemView.findViewById(R.id.media_view)
          val ad_price:TextView=itemView.findViewById(R.id.ad_price)
          val ad_store:TextView=itemView.findViewById(R.id.ad_store)
          val ad_call_to_action: Button =itemView.findViewById(R.id.ad_call_to_action)
          val native_Ad_View: NativeAdView =itemView.findViewById(R.id.native_Ad_View)
  
      }
  
  
  
  }
  
• How to fill the spinner with a custom object with coroutines and implement your onItemSelected logic related to that object?

  For example, let's use this class:

  data class Person (
      var id : Long,
      var name: String,
      var imageUrl: String
  )
  

  I need to fill my spinner with name values from the custom objects of Person, and when some value is selected in spinner, I need to update the image according to the imageUrl in the selected object.

  Is there any other way to make that than overriding toString() function in Person? For example, if I have to use Person class somewhere else where I need another toString implementation

  Also I'm getting the List of Persons from api/room through kotlin coroutines

  private fun collectFlows(){
          lifecycleScope.launchWhenStarted {
              repeatOnLifecycle(Lifecycle.State.STARTED){
                  mainViewModel.personStateFlow.collectLatest {
                      // update adapter's list
                  }
              }
          }
  

  so how to always update the list in adapter when it changes? I know how to make it with custom adapter for RecyclerView, but I'm confused about how to make such thing with spinner adapter.
• How can i place my Spinner(DropDown) on top of a WebView in Kotlin?

  im new to Android development. I think i got kinda the basics, but after 8 workhours of not getting my DropDown above my WebView, i tought i gotta ask.

  class MainActivity : AppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      val languages = resources.getStringArray(R.array.array1)
  
       val webview = WebView(this)
      setContentView(webview)
       webview.settings.javaScriptEnabled = true
     webview.loadUrl("http://localhost/test/neu/index.php")
  
  
      // access the spinner
      val spinner = findViewById<Spinner>(R.id.spinner1)
      if (spinner != null) {
          val adapter = ArrayAdapter(this,
              android.R.layout.simple_spinner_item, languages)
          spinner.adapter = adapter
  
          spinner.onItemSelectedListener = object :
              AdapterView.OnItemSelectedListener {
              override fun onItemSelected(parent: AdapterView<*>,
                                          view: View, position: Int, id: Long) {
                  Toast.makeText(this@MainActivity,
                      getString(R.string.selected_item) + " " +
                              "" + languages[position], Toast.LENGTH_SHORT).show()
              }
  
              override fun onNothingSelected(parent: AdapterView<*>) {
                  // write code to perform some action
              }
          }
      }
  }
  

  It does what it's supposed to do, the only thing is it places the Spinner below the WebView. If i comment out line 5-8 inside the onCreate(), it shows me a white screen with only the Spinner.

  Looking for Answers to this question just brings me SO threads on how to make a Progress bar, which i dont get, but w/e. Thanks in advance

  My Manifest.xml:

  <manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.example.ttermscannerandroid51">
  <uses-permission android:name="android.permission.INTERNET" />
  
  <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/Theme.TTermScannerAndroid51">
      <activity
          android:name=".MainActivity"
          android:exported="true">
          <intent-filter>
              <action android:name="android.intent.action.MAIN" />
  
              <category android:name="android.intent.category.LAUNCHER" />
          </intent-filter>
      </activity>
  </application>
  

  at last my 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">
  
      <WebView
          android:id="@+id/WebView"
          android:layout_width="0dp"
          android:layout_height="0dp"
          android:layout_marginStart="1dp"
          android:layout_marginTop="1dp"
          android:layout_marginEnd="1dp"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintHorizontal_bias="0.377"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintVertical_bias="0.0">
  
          <Spinner
              android:id="@+id/spinner1"
              android:layout_width="100dp"
              android:layout_height="100dp"
              android:spinnerMode="dropdown" />
      </WebView>
  </androidx.constraintlayout.widget.ConstraintLayout>
  
• How to build a unit conversion app in java and android studio

  I'm trying to build my first project which is a unit conversion app in java and android studio. My question is how to build the app using a spinner which the user says which unit he wants to convert from and another spinner to choose the unit he wants to convert to and edit text to enter the value and another edit text to show the result. Please help me its for my junior project and thank you.
• Reduce empty space between pickers in Android DatePicker

  I have a limited space for an Android DatePicker, as is in screenshot below. How can I reduce the two empty space between the pickers, so as to have the necessary space for them?

  Screenshot

  I want to reduce only this white space, not to reduce dimensions (with scaleX property) of the entire DatePicker.

  XML code of DatePicker:

  DatePicker
      android:id="@+id/dateNascitaEmissione"
      android:layout_width="@dimen/emissione_dateNascita_width"
      android:layout_height="@dimen/emissione_dateNascita_height"
      android:layout_below="@id/labelPasseggeroEmissione"
      android:layout_toEndOf="@id/labelNascitaEmissione"
      android:layout_alignEnd="@id/labelPasseggeroEmissione"
      android:layout_gravity="top|left"
      android:gravity="left"
      android:calendarTextColor="@color/grayVeryDark"
      android:textSize="@dimen/emissione_dateNascita_text_size"
      android:calendarViewShown="false"
      android:datePickerMode="spinner"
      android:firstDayOfWeek="2"
      android:spinnersShown="true"
      android:clickable="false"
      android:longClickable="false"
      android:focusable="false"
      android:enabled="true"
      android:visibility="visible"
  
• Trying to get Calendar data into a String [Solved]

  Trying to store data into a string.

  This is my utilities.

  public class CommonDatePicker {
  
  public static  void datePicker(final TextView textView, Context context) {
    Calendar dateCalender = Calendar.getInstance();
    final int year = dateCalender.get(Calendar.YEAR);
    final   int month = dateCalender.get(Calendar.MONTH);
    final int day = dateCalender.get(Calendar.DAY_OF_MONTH);
  
  
    DatePickerDialog datePickerDialog;
    datePickerDialog = new DatePickerDialog(context, new DatePickerDialog.OnDateSetListener() {
       @Override
       public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
          monthOfYear = monthOfYear + 1;
          //2001-05-03
          // dayOfMonth  monthOfYear
          String formattedMonth = "" + monthOfYear;
          String formattedDayOfMonth = "" + dayOfMonth;
  
          if(monthOfYear < 10){
  
             formattedMonth = "0" + monthOfYear;
          }
          if(dayOfMonth < 10){
  
             formattedDayOfMonth  = "0" + dayOfMonth ;
          }
          //editText.setText( formattedDayOfMonth + "-" + formattedMonth + "-" + year);
          textView.setText( year + "-" + formattedMonth + "-" + formattedDayOfMonth);
  
       }
  
    }, year, month, day);
    datePickerDialog.setTitle("SELECT DATE");
    datePickerDialog.show();
     }
   }
  

  This is where I'm trying to get data. After clicking on textView the datePicker appears as expected but I want to store picked data into a string. I don't know how to do it.

  This is my main.java

  txt_data_collection_date.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              CommonDatePicker.datePicker(txt_data_collection_date, TofsilForm10Activity.this);
              //String date; I want to store data in date.
          }
      });
  
• Update TextView When Date is Changed in the DatePicker

  I have Added A date picker View in my .xml layout

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        android:id="@+id/datePicker"
        android:layout_width="wrap_content"
        android:layout_height="150dp"
        android:calendarViewShown="false"
        android:datePickerMode="spinner"
        app:layout_constraintEnd_toStartOf="@+id/age"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView6" />
  

  and a text view which should show the age of the user

   val year = binding.datePicker.year.toString().toInt()
   val cd = Calendar.getInstance().get(Calendar.YEAR).toString().toInt()
   val agu = cd - year binding.age.text = "$agu\nYears"
  

  When the app is launched, the age does not update when I change the values in the date picker. How to update the textview whenever I change the year in date picker?
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• Referencing multiple buttons efficiently in Kotlin

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• how to debug my stack traces related to crashing the app with imagebutton

  hi i have a activity that has information about my company and i must referring to this by a imagebutton in mainactivity, i wrote following java codes in infoscreen.java:

  package com.journaldev.webview;
  
  import android.os.Bundle;
  import android.util.Log;
  import android.widget.TextView;
  
  import androidx.appcompat.app.AppCompatActivity;
  
  public class infoscreen extends AppCompatActivity {
  
  private static final String TAG = "infoscreen";
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_infoscreen);
  
      TextView theTextView = (TextView) findViewById(R.id.infotext);
  
      theTextView.setText("aboutus");
  
      String stringFromTextView = theTextView.getText().toString();
      System.out.println(stringFromTextView);
  
      Log.d(TAG, "onCreate: " + stringFromTextView);
  
  }
  }
  

  my MainActivity.java file is :

      infobtn = findViewById(R.id.info_btn);
  
  
      infobtn.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              startActivity(new Intent(MainActivity.this,infoscreen.class));
          }
                                 });
  

  but when i run by HMD Global Nokia 7.2, app crashes and show below stack traces:

  2022-01-04 13:40:00.411 19746-19746/com.journaldev.webview E/AndroidRuntime: FATAL EXCEPTION: main Process: com.journaldev.webview, PID: 19746 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.journaldev.webview/com.journaldev.webview.MainActivity}: java.lang.ClassCastException: androidx.appcompat.widget.AppCompatImageButton cannot be cast to android.widget.Button at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3271) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3410) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2017) at android.os.Handler.dispatchMessage(Handler.java:107) at android.os.Looper.loop(Looper.java:214) at android.app.ActivityThread.main(ActivityThread.java:7397) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935) Caused by: java.lang.ClassCastException: androidx.appcompat.widget.AppCompatImageButton cannot be cast to android.widget.Button at com.journaldev.webview.MainActivity.onCreate(MainActivity.java:37) at android.app.Activity.performCreate(Activity.java:7993) at android.app.Activity.performCreate(Activity.java:7982) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3246) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3410)  at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)  at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)  at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2017)  at android.os.Handler.dispatchMessage(Handler.java:107)  at android.os.Looper.loop(Looper.java:214)  at android.app.ActivityThread.main(ActivityThread.java:7397)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935) 

  what means these stack traces? and how to fix them until i can launch app correctly?