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Why is this code being executed when the user have not selected anything? [duplicate]

I created an Android application with a Spinner and a TextView. I want to display the selected item from the Spinner's drop down list in the TextView. I implemented the Spinner in the onCreate method so when I'm running the program, it shows a value in the TextView (before selecting an item from the drop down list).
I want to show the value in the TextView only after selecting an item from the drop down list. How do I do this?
Here is my code:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
public class GPACal01Activity extends Activity implements OnItemSelectedListener {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Spinner spinner = (Spinner) findViewById(R.id.noOfSubjects);
// Create an ArrayAdapter using the string array and a default spinner layout
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,R.array.noofsubjects_array, android.R.layout.simple_spinner_item);
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(this);
}
public void onItemSelected(AdapterView<?> parent, View arg1, int pos,long id) {
TextView textView = (TextView) findViewById(R.id.textView1);
String str = (String) parent.getItemAtPosition(pos);
textView.setText(str);
}
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
}

spinner.setOnItemSelectedListener(this); // Will call onItemSelected() Listener.
So first time handle this with any Integer value
Example:
Initially Take int check = 0;
public void onItemSelected(AdapterView<?> parent, View arg1, int pos,long id) {
if(++check > 1) {
TextView textView = (TextView) findViewById(R.id.textView1);
String str = (String) parent.getItemAtPosition(pos);
textView.setText(str);
}
}
You can do it with boolean value and also by checking current and previous positions. See here

Just put this line before setting the OnItemSelectedListener
spinner.setSelection(0,false)
This works because setSelection(int, boolean) calls setSelectionInt() internally so that when the listener is added, the item is already selected.
Beware that setSelection(int) won't work, because it calls setNextSelectedPositionInt() internally.

Beginning with API level 3 you can use onUserInteraction() on an Activity with a boolean to determine if the user is interacting with the device.
http://developer.android.com/reference/android/app/Activity.html#onUserInteraction()
#Override
public void onUserInteraction() {
super.onUserInteraction();
userIsInteracting = true;
}
As a field on the Activity I have:
private boolean userIsInteracting;
Finally, my spinner:
mSpinnerView.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> arg0, View view, int position, long arg3) {
spinnerAdapter.setmPreviousSelectedIndex(position);
if (userIsInteracting) {
updateGUI();
}
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
As you come and go through the activity the boolean is reset to false. Works like a charm.

This worked for me
Spinner's initialization in Android is problematic sometimes
the above problem was solved by this pattern.
Spinner.setAdapter();
Spinner.setSelected(false); // must
Spinner.setSelection(0,true); //must
Spinner.setonItemSelectedListener(this);
Setting adapter should be first part and onItemSelectedListener(this) will be last when initializing a spinner. By the pattern above my OnItemSelected() is not called during initialization of spinner

haha...I have the same question.
When initViews() just do like this.The sequence is the key, listener is the last. Good Luck !
spinner.setAdapter(adapter);
spinner.setSelection(position);
spinner.setOnItemSelectedListener(listener);

To avoid calling spinner.setOnItemSelectedListener() during initialization
spinner.setSelection(Adapter.NO_SELECTION, true); //Add this line before setting listener
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});

My solution:
protected boolean inhibit_spinner = true;
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1,
int pos, long arg3) {
if (inhibit_spinner) {
inhibit_spinner = false;
}else {
if (getDataTask != null) getDataTask.cancel(true);
updateData();
}
}

You can do this by this way:
AdapterView.OnItemSelectedListener listener = new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
//set the text of TextView
}
#Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
yourSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
yourSpinner.setOnItemSelectedListener(listener);
}
#Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
At first I create a listener and attributed to a variable callback; then i create a second listener anonymous and when this is called at a first time, this change the listener
=]

The user interaction flag can then be set to true in the onTouch method and reset in onItemSelected() once the selection change has been handled. I prefer this solution because the user interaction flag is handled exclusively for the spinner, and not for other views in the activity that may affect the desired behavior.
In code:
Create your listener for the spinner:
public class SpinnerInteractionListener implements AdapterView.OnItemSelectedListener, View.OnTouchListener {
boolean userSelect = false;
#Override
public boolean onTouch(View v, MotionEvent event) {
userSelect = true;
return false;
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (userSelect) {
userSelect = false;
// Your selection handling code here
}
}
}
Add the listener to the spinner as both an OnItemSelectedListener and an OnTouchListener:
SpinnerInteractionListener listener = new SpinnerInteractionListener();
mSpinnerView.setOnTouchListener(listener);
mSpinnerView.setOnItemSelectedListener(listener);

create a boolean field
private boolean inispinner;
inside oncreate of the activity
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (!inispinner) {
inispinner = true;
return;
}
//do your work here
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});

Similar simple solution that enables multiple spinners is to put the AdapterView in a collection - in the Activities superclass - on first execution of onItemSelected(...) Then check to see if the AdapterView is in the collection before executing it. This enables one set of methods in the superclass and supports multiple AdapterViews and therefor multiple spinners.
Superclass ...
private Collection<AdapterView> AdapterViewCollection = new ArrayList<AdapterView>();
protected boolean firstTimeThrough(AdapterView parent) {
boolean firstTimeThrough = ! AdapterViewCollection.contains(parent);
if (firstTimeThrough) {
AdapterViewCollection.add(parent);
}
return firstTimeThrough;
}
Subclass ...
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (! firstTimeThrough(parent)) {
String value = safeString(parent.getItemAtPosition(pos).toString());
String extraMessage = EXTRA_MESSAGE;
Intent sharedPreferencesDisplayIntent = new Intent(SharedPreferencesSelectionActivity.this,SharedPreferencesDisplayActivity.class);
sharedPreferencesDisplayIntent.putExtra(extraMessage,value);
startActivity(sharedPreferencesDisplayIntent);
}
// don't execute the above code if its the first time through
// do to onItemSelected being called during view initialization.
}

Try this
spinner.postDelayed(new Runnable() {
#Override
public void run() {
addListeners();
}
}, 1000);.o

Code
spinner.setOnTouchListener(new View.OnTouchListener() {
#Override public boolean onTouch(View view, MotionEvent motionEvent) { isSpinnerTouch=true; return false; }});
holder.spinner_from.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> adapterView, View view, int slot_position, long l) {
if(isSpinnerTouch)
{
Log.d("spinner_from", "spinner_from");
spinnerItemClickListener.onSpinnerItemClickListener(position, slot_position, AppConstant.FROM_SLOT_ONCLICK_CODE);
}
else {
}
}
#Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});

You could achieve it by setOnTouchListener first then setOnItemSelectedListener in onTouch
#Override
public boolean onTouch(final View view, final MotionEvent event) {
view.setOnItemSelectedListener(this)
return false;
}

This worked for me:
spinner.setSelection(0, false);
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
spinner.setOnItemSelectedListener(listener);
}, 500);

Based on Abhi's answer i made this simple listener
class SpinnerListener constructor(private val onItemSelected: (position: Int) -> Unit) : AdapterView.OnItemSelectedListener {
private var selectionCount = 0
override fun onNothingSelected(parent: AdapterView<*>?) {
//no op
}
override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
if (selectionCount++ > 1) {
onItemSelected(position)
}
}
}

You can create custom OnItemSelectedListener like this. I've taken val check=0 and in onItemSelected() method i did check if its count is 0? If 0 means its called during initialization. So simply ignore it.
I've also called separate abstract method called onUserItemSelected() I'll call this method is check > 0. This works perfectly fine for me.
abstract class MySpinnerItemSelectionListener : AdapterView.OnItemSelectedListener {
abstract fun onUserItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long)
private var check = 0
override fun onItemSelected(
parent: AdapterView<*>?,
view: View,
position: Int,
id: Long
) {
if (++check > 1) {
onUserItemSelected(parent, view, position, id)
}
}
override fun onNothingSelected(parent: AdapterView<*>?) {}
}
And then you can set listener like this.
mySpinner.onItemSelectedListener = object : MySpinnerItemSelectionListener() {
override fun onUserItemSelected(
parent: AdapterView<*>?,
view: View?,
position: Int,
id: Long
) {
//your user selection spinner code goes here
}
}

Had the same problem and this works for me:
I have 2 spinners and I update them during init and during interactions with other controls or after getting data from the server.
Here is my template:
public class MyClass extends <Activity/Fragment/Whatever> implements Spinner.OnItemSelectedListener {
private void removeSpinnersListeners() {
spn1.setOnItemSelectedListener(null);
spn2.setOnItemSelectedListener(null);
}
private void setSpinnersListeners() {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
spn1.setOnItemSelectedListener(MyClass.this);
spn2.setOnItemSelectedListener(MyClass.this);
}
}, 1);
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
// Your code here
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
}
When the class is initiating use setSpinnersListeners() instead of directly setting the listener.
The Runnable will prevent the spinner from firing onItemSelected right after the you set their values.
If you need to update the spinner (after a server call etc.) use removeSpinnersListeners() right before your update lines, and setSpinnersListeners() right after the update lines. This will prevent onItemSelected from firing after the update.

For me, Abhi's solution works great up to Api level 27.
But it seems that from Api level 28 and upwards, onItemSelected() is not called when listener is set, which means onItemSelected() is never called.
Therefore, I added a short if-statement to check Api level:
public void onItemSelected(AdapterView<?> parent, View arg1, int pos,long id) {
if(Build.VERSION.SDK_INT >= 28){ //onItemSelected() doesn't seem to be called when listener is set on Api 28+
check = 1;
}
if(++check > 1) {
//Do your action here
}
}
I think that's quite weird and I'm not sure wether others also have this problem, but in my case it worked well.

I placed a TextView on top of the Spinner, same size and background as the Spinner, so that I would have more control over what it looked like before the user clicks on it. With the TextView there, I could also use the TextView to flag when the user has started interacting.
My Kotlin code looks something like this:
private var mySpinnerHasBeenTapped = false
private fun initializeMySpinner() {
my_hint_text_view.setOnClickListener {
mySpinnerHasBeenTapped = true //turn flag to true
my_spinner.performClick() //call spinner click
}
//Basic spinner setup stuff
val myList = listOf("Leonardo", "Michelangelo", "Rafael", "Donatello")
val dataAdapter: ArrayAdapter<String> = ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, myList)
my_spinner.adapter = dataAdapter
my_spinner.onItemSelectedListener = object : OnItemSelectedListener {
override fun onItemSelected(parent: AdapterView<*>?, view: View, position: Int, id: Long) {
if (mySpinnerHasBeenTapped) { //code below will only run after the user has clicked
my_hint_text_view.visibility = View.GONE //once an item has been selected, hide the textView
//Perform action here
}
}
override fun onNothingSelected(parent: AdapterView<*>?) {
//Do nothing
}
}
}
Layout file looks something like this, with the important part being that the Spinner and TextView share the same width, height, and margins:
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Spinner
android:id="#+id/my_spinner"
android:layout_width="match_parent"
android:layout_height="35dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:background="#drawable/bg_for_spinners"
android:paddingStart="8dp"
android:paddingEnd="30dp"
android:singleLine="true" />
<TextView
android:id="#+id/my_hint_text_view"
android:layout_width="match_parent"
android:layout_height="35dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:background="#drawable/bg_for_spinners"
android:paddingStart="8dp"
android:paddingEnd="30dp"
android:singleLine="true"
android:gravity="center_vertical"
android:text="*Select A Turtle"
android:textColor="#color/green_ooze"
android:textSize="16sp" />
</FrameLayout>
I'm sure the other solutions work where you ignore the first onItemSelected call, but I really don't like the idea of assuming it will always be called.

I solved this problem like this:
In the activity lifecycle method whose name is onResume():
I added Spinner.setOnItemSelectedListener(this);
As a result, when our spinner call onclick method in the initialize, it does not work.
onResume method starts working when the finished Android page is displayed.

Android Spinner load with empty value (popup is shown before populating data)

I am using https://github.com/Chivorns/SmartMaterialSpinner Library for spinner.
When i first click the spinner no adapter is attached to it or spinner items shows empty list..
like
but when i close it and again select it.. data are shown so I believe that .. due to time consuming data fetching .. spinner show empty dialog.. Now I need to handle that.. How can i only show spinner when data is populated or available.. I have tried async task and handler but not get working.. any hint would be appreciated.. Thank you
Edited ...
I have call api on spinner onTouch event to populate data
{
private void ProvinceSpinnerCode(boolean IsEditCase) {
if (IsEditCase) {
//edit case condition
} else {
provinceSpinner.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
mService = RetrofitManager.getApiClient().create(RetrofitInstance.class);
Call<List<SelectModel>> provinceCall = mService.GetProvinces();
provinceCall.enqueue(new Callback<List<SelectModel>>() {
#Override
public void onResponse(Call<List<SelectModel>> call, Response<List<SelectModel>> response) {
if (response.body().size() >= 0) {
provinceSpinner.setAdapter(new SpinnerAdapter(response.body(),AddCustomerActivity.this));
}
}
#Override
public void onFailure(Call<List<SelectModel>> call, Throwable t) {
}
});
return false;
}
});
}
provinceSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(AddCustomerActivity.this, "Id is : " + id, Toast.LENGTH_SHORT).show();
provinceId = (int) id;
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}

You are making an API call inside on touch event which will be fired when you will touch the spinner so to solve the problem just do Api call out side that event (may be inside Oncreate).
Right now provinceSpinner has a touch listerner so when you are touching it to open for the first time it is Fetching data so when you are clicking it again the alert is showing data (the data you fetched when you clicked first time)

Android: animateLayoutChanges(false) programmatically giving NullPointerException

This is not duplicate of 'animateLayoutChanges programmatically'.
I want the default animation effects on my view changes except from the fade out effect on removing the objects. I cannot use disableTransitionType() because it was added in API 16. All I could think of was disabling the android:animateLayoutChanges to false, remove the view and setting it again to true. In my recyclerView I thought of removing the animation by holder.rootView.setLayoutTansition(null). But unfortunately it is giving me NullPointerException.
A part of my code is something like this:
#Override
public void onBindViewHolder(final MyViewHolder holder, int position) {
SavedMessagePackage current = data.get(position);
final String message = current.message;
holder.message.setText(message);
holder.message.setMaxLines(2);
holder.message.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (holder.button.getVisibility() == View.GONE) {
holder.button.setVisibility(View.VISIBLE);
holder.message.setMaxLines(Integer.MAX_VALUE);
holder.message.setText(message);
}
else if (holder.button.getVisibility() == View.VISIBLE) {
holder.root_view.setLayoutTransition(null); // NullPointerException
holder.button.setVisibility(View.GONE);
holder.message.setMaxLines(2);
holder.root_view.setLayoutTransition(new LayoutTransition());
}
}
});
holder.button.setVisibility(View.GONE);
}
How can I achieve this?

In your case you could have holder or root_view being null, but since holder was accessed successfully before, so root_view is null.
Therefore it's most likely you didn't assign holder.root_view before.

NotifyDataSetChanged in activity with adapter

i have this in my activity:
mylistCodelist.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
try {
if (codeAction == 1) {
if (Schedario.returnNewListCode().size() == 1) {
Schedario.returnListDimensionList()
.get(Schedario.parentPosition)
.setChecked(false);
} else {
Schedario.returnListDimensionList()
.get(Schedario.parentPosition)
.setChecked(true);
}
Schedario.returnNewListCode().get(position)
.setChecked(true);
}
synchronized (view) {
view.notifyAll();
}
I want that when I click on an item, the list is updated in the adapter.
I also tried to add this:
synchronized (mylistCodelist) {
mylistCodelist.notifyAll();
}
but does not work.
how can I solve this problem?
Thanks in advance

You need to call adapter.notifyDatasetChanged(). This will update your list view when new data has arrived.
What I grasp from your question is that when the button is clicked, you want your list to be updated based on some criteria, right?

User Input causes form to appear

I want to have EditText object appear when a the User chooses "Combination" on a Spinner, How would I do this?
Here is what I have been trying:
ground = (Spinner) findViewById(R.id.ground);
ArrayAdapter<CharSequence> groundAdapter = ArrayAdapter.createFromResource(
this, R.array.ground_array, android.R.layout.simple_spinner_item);
groundAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
ground.setAdapter(groundAdapter);
ground.setOnItemSelectedListener(new GroundListener());
if(ground.getSelectedItem().toString().equalsIgnoreCase("Combination"))
{
combo.setVisibility(0);
}
the EditText object combo is set in xml file as android:visibility="gone"
GroundListener Code is
public class GroundListener implements OnItemSelectedListener {
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
String selected = parent.getItemAtPosition(pos).toString();
}
public void onNothingSelected(AdapterView parent)
{
// Do nothing.
}
}

What is a GroundListener ?
Shouldn't you be using an AdapterView.OnItemSelectedListener with its onItemSelected method ?
Beside, use setVisibility(View.VISIBLE) instead of 0 for readability.
EDIT:
I don't understand what you are doing with your code, your GroundListener is not plugged to anything and your test is outside of the listener.
Try :
ground.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if(parent.getItemAtPosition(pos).toString().equalsIgnoreCase("Combination"))
{
combo.setVisibility(View.VISIBLE);
}
}
public void onNothingSelected(AdapterView parent)
{
// Do nothing.
}
});
Check if that works and then bring back the code in your GroundListener to see if it works. You might have a problem though with the fact that the GroundListener might not know what is combo. But you'll work that out.
Edit:
Syntax Correction