Spinner: get state or get notified when opens

Question

Is it possible to know whether a Spinner is open or closed? It would even be better if there was some sort of onOpenListener for Spinners.

I've tried using an OnItemSelectedListener like this:

spinnerType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            executeSomething();

        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            Log.d("nothing" , "selected");  
        }

    });

I can know that the window will close if something is selected (in executeSomething()). But I don't get notified if I click outside of the Dialog, which also closes the spinner

Answer 1

Another option to watch for those events is to extend the Spinner class and use one of its methods(performClick() which will trigger its dialog/popup) followed by monitoring the focus of the window holding this custom Spinner. This should provide you with the wanted closed event for all the possible finishing possibilities(for either the dialog or dropdown mode).

The custom Spinner class:

public class CustomSpinner extends Spinner {

   /**
    * An interface which a client of this Spinner could use to receive
    * open/closed events for this Spinner. 
    */
    public interface OnSpinnerEventsListener {

        /**
         * Callback triggered when the spinner was opened.
         */
         void onSpinnerOpened(Spinner spinner);

        /**
         * Callback triggered when the spinner was closed.
         */
         void onSpinnerClosed(Spinner spinner);

    }

    private OnSpinnerEventsListener mListener;
    private boolean mOpenInitiated = false;

    // implement the Spinner constructors that you need

    @Override
    public boolean performClick() {
        // register that the Spinner was opened so we have a status
        // indicator for when the container holding this Spinner may lose focus
        mOpenInitiated = true;
        if (mListener != null) {
            mListener.onSpinnerOpened(this);
        }
        return super.performClick();
    }

    @Override
    public void onWindowFocusChanged (boolean hasFocus) {
        if (hasBeenOpened() && hasFocus) {
            performClosedEvent();
        }
    }

    /**
    * Register the listener which will listen for events.
    */
    public void setSpinnerEventsListener(
            OnSpinnerEventsListener onSpinnerEventsListener) {
        mListener = onSpinnerEventsListener;
    }

    /**
     * Propagate the closed Spinner event to the listener from outside if needed.
     */
    public void performClosedEvent() {
        mOpenInitiated = false;
        if (mListener != null) {
            mListener.onSpinnerClosed(this);
        }
    }

    /**
     * A boolean flag indicating that the Spinner triggered an open event.
     * 
     * @return true for opened Spinner 
     */
    public boolean hasBeenOpened() {
        return mOpenInitiated;
    }

}

Answer 2

There's no built in function but it's pretty easy to do with an OnTouchListener and OnItemSelectedListener.

abstract class OnOpenListener implements OnTouchListener, OnItemSelectedListener {

    public OnOpenListener(Spinner spinner) {
        spinner.setOnTouchListener(this);
        spinner.setOnItemSelectedListener(this);
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_UP) {
            onOpen();
        }
        return false;
    }

    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        onClose();
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        onClose();
    }

    abstract public void onOpen();

    abstract public void onClose();
}

And then assign the appropriate listeners:

    OnOpenListener onOpenListener = new OnOpenListener(mySpinner) {

        @Override
        public void onOpen() {
            // spinner was opened
        }

        @Override
        public void onClose() {
            // spinner was closed
        }
    };

Answer 3

After spending the day looking at all the solutions, here is my easy fix for detecting the opening and closing of Spinner and also how focusing outside spinner closes the spinner.

Step 1: Adding a addOnWindowFocusChangeListener to your Spinner in Fragment or Activity.

 override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)

    val spinner = spinner_view

    val arrayAdapter = ArrayAdapter<RestoreManager.ConnectionType>(context!!, R.layout.layout_backup_spinner)
    arrayAdapter.setDropDownViewResource(R.layout.spinner_item)

    spinner?.let {
        val spinnerAdapter = SpinnerAdapter(activity!!)
        it.adapter = spinnerAdapter 
        it.setSelection(0)

        it.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
            override fun onItemSelected(parentView: AdapterView<*>, selectedItemView: View?, position: Int, id: Long) {}

            override fun onNothingSelected(parentView: AdapterView<*>) {}
        }

        it.viewTreeObserver?.addOnWindowFocusChangeListener { hasFocus -> //This updates the arrow icon up/down depending on Spinner opening/closing
            spinnerAdapter .spinnerOpen = hasFocus
            spinnerAdapter .notifyDataSetChanged()
        }
    }
}

addOnWindowFocusChangeListener is called every time the spinner opens or closes. It also get triggered when spinner is open and user tap outside the spinner to close the spinner. In this method you can update the UI of your SpinnerAdapter.

For my use case, i wanted to show the arrow icon up and down when the spinner opens and closes. So i set the flag spinnerAdapter.spinnerOpen in my Spinner Adapter.

Step 2: In your SpinnerAdapter override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {} is called every time spinner open or close. Here is the code in SpinnerAdapter:

override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
    val spinView = if (convertView == null) {
        val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        inflater.inflate(R.layout.layout_backup_spinner, null)
    } else {
        convertView
    }

    var arrowIcon = spinView.findViewById<ImageView>(R.id.arrow_icon)
    if (spinnerOpen) arrowIcon.setImageResource(R.drawable.arrow_down)
    else arrowIcon.setImageResource(R.drawable.arrow_up)

    return spinView
}

Answer 4

I could not find a way to get this behaviour with the spinner so the only thing that worked for me was to use the spinner (custom) adapter instead:

public interface SpinnerListener {

    void onSpinnerExpanded();   

    void onSpinnerCollapsed();
}

Then a custom adapter can be written that just grabs the “spinner expanded” view and adds a listener to it to listen for “expand” and “collapse” events. The custom adapter I used is:

public class ListeningArrayAdapter<T> extends ArrayAdapter<T> {
        private ViewGroup itemParent;
        private final Collection<SpinnerListener> spinnerListeners = new ArrayList<SpinnerListener>();

    public ListeningArrayAdapter(Context context, int resource, T[] objects) {
        super(context, resource, objects);
    }

    // Add the rest of the constructors here ...


    // Just grab the spinner view (parent of the spinner item view) and add a listener to it.
    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        if (isParentTheListView(parent)) {
            itemParent = parent;
            addFocusListenerAsExpansionListener();
        }

        return super.getDropDownView(position, convertView, parent);
    }

    // Assumes the item view parent is a ListView (which it is when a Spinner class is used)
    private boolean isParentTheListView(ViewGroup parent) {
        return (parent != itemParent && parent != null && ListView.class.isAssignableFrom(parent.getClass()));      
    }

    // Add a focus listener to listen to spinner expansion and collapse events.
    private void addFocusListenerAsExpansionListener() {
        final View.OnFocusChangeListener listenerWrapper = new OnFocusChangeListenerWrapper(itemParent.getOnFocusChangeListener(), spinnerListeners);
        itemParent.setOnFocusChangeListener(listenerWrapper);       
    }

    // Utility method.
    public boolean isExpanded() {
        return (itemParent != null && itemParent.hasFocus());
    }

    public void addSpinnerListener(SpinnerListener spinnerListener) {
        spinnerListeners.add(spinnerListener);
    }

    public boolean removeSpinnerListener(SpinnerListener spinnerListener) {
        return spinnerListeners.remove(spinnerListener);    
    }

    // Listener that listens for 'expand' and 'collapse' events.
    private static class OnFocusChangeListenerWrapper implements View.OnFocusChangeListener {
        private final Collection<SpinnerListener> spinnerListeners;
        private final View.OnFocusChangeListener originalFocusListener;

        private OnFocusChangeListenerWrapper(View.OnFocusChangeListener originalFocusListener, Collection<SpinnerListener> spinnerListeners) {
            this.spinnerListeners = spinnerListeners;
            this.originalFocusListener = originalFocusListener;
        }

        @Override
        public void onFocusChange(View view, boolean hasFocus) {
            if (originalFocusListener != null) {
                originalFocusListener.onFocusChange(view, hasFocus); // Preserve the pre-existing focus listener (if any).
            }

            callSpinnerListeners(hasFocus);
        }

        private void callSpinnerListeners(boolean hasFocus) {
            for (SpinnerListener spinnerListener : spinnerListeners) {
                if (spinnerListener != null) {
                    callSpinnerListener(hasFocus, spinnerListener);
                }
            }           
        }

        private void callSpinnerListener(boolean hasFocus, SpinnerListener spinnerListener) {
            if (hasFocus) {
                spinnerListener.onSpinnerExpanded();
            }
            else {
                spinnerListener.onSpinnerCollapsed();
            }           
        }
    }
}

Then when I use a spinner in my activity or fragment all I had to do was to set the spinner adapter to the above custom adapter:

private ListeningArrayAdapter<CharSequence> adapter;

private Spinner buildSpinner() {
    final CharSequence[] items = {"One", "Two", "Three"};
    final Spinner spinner = (Spinner)getActivity().getLayoutInflater().inflate(R.layout.item_spinner, null);            
    adapter = new ListeningArrayAdapter<CharSequence>(getActivity(), R.layout.item_spinner_item, items);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    adapter.addSpinnerListener(new TestSpinnerListener(getActivity())); // Add your own spinner listener implementation here.
    spinner.setAdapter(adapter);

    return spinner;
}

I know that this is a bit of a hack and a a bit brittle but it worked for me. It would be much better if the Spinner class had all this functionality build in and allowed you to set an expand-collapse listener. For the time being I will have to do with this hack.

Answer 5

You need to use Reflection and get access to the private field 'mPopup' and then set the method setOnDismissListener(), which is triggered when the pop-up is closed no matter it the user clicks on the empty area or selects new item. You can learn more about how it works here: https://stackoverflow.com/a/69156679/3753104

Here is the full source code for the custom Spinner

open class CustomSpinner: androidx.appcompat.widget.AppCompatSpinner {

    constructor(context: Context) : super(context)
    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)
    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr)

    lateinit var listPopupWindow: ListPopupWindow
    lateinit var onPopUpClosedListener: (dropDownMenu: DropDownMenu) -> Unit
    lateinit var onPopUpOpenedListener: (dropDownMenu: DropDownMenu) -> Unit

    init {

        try {

            // get the listPopupWindow
            val listPopupWindowField = androidx.appcompat.widget.AppCompatSpinner::class.java.getDeclaredField("mPopup")
            listPopupWindowField.isAccessible = true
            listPopupWindow = listPopupWindowField.get(this) as ListPopupWindow
            listPopupWindow.isModal = false

        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

    override fun performClick(): Boolean {
        val returnValue = super.performClick()

        // indicate that the pop-up was opened
        if (::onPopUpOpenedListener.isInitialized) {
            onPopUpOpenedListener.invoke(this)
        }

        try {

            // get the popupWindow
            val popupWindowField = ListPopupWindow::class.java.getDeclaredField("mPopup")
            popupWindowField.isAccessible = true
            val popupWindow = popupWindowField.get(listPopupWindow) as PopupWindow

            // get the original onDismissListener
            val onDismissListenerField = PopupWindow::class.java.getDeclaredField("mOnDismissListener")
            onDismissListenerField.isAccessible = true
            val onDismissListener = onDismissListenerField.get(popupWindow) as PopupWindow.OnDismissListener

            // now override the original OnDismissListener
            listPopupWindow.setOnDismissListener {

                // indicate that the pop-up was closed
                if (::onPopUpClosedListener.isInitialized) {
                    onPopUpClosedListener.invoke(this)
                }

                // now we need to call the original listener that will remove the global OnLayoutListener
                onDismissListener.onDismiss()
            }

        } catch (e: Exception) {
            e.printStackTrace()
        }

        return returnValue
    }
}

And then simply attach listeners to your custom spinner

val customSpinner = findViewById<CustomSpinner>(R.id.mySpinner)
customSpinner.onPopUpClosedListener = { spinner: CustomSpinner ->
    // called when the pop-up is closed
}

customSpinner.onPopUpOpenedListener = { spinner: CustomSpinner ->
    // called when the pop-up is opened      
}

Answer 6

based on @Luksprog wonderful solution,i just want to add a small change which will be very helpful in case someone is using the CustomSpinner inside a fragment. instead of using the Activity.onWindowFocusChanged function, we override the View.onWindowFocusChanged function. thus the whole CustomSpinner class become

import android.content.Context;
import android.util.AttributeSet;
import android.widget.Spinner;

public class CustomSpinner extends Spinner {
    private static final String TAG = "CustomSpinner";
    private OnSpinnerEventsListener mListener;
    private boolean mOpenInitiated = false;

    public CustomSpinner(Context context, AttributeSet attrs, int defStyleAttr, int mode) {
        super(context, attrs, defStyleAttr, mode);
    }

    public CustomSpinner(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public CustomSpinner(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomSpinner(Context context, int mode) {
        super(context, mode);
    }

    public CustomSpinner(Context context) {
        super(context);
    }

    public interface OnSpinnerEventsListener {

        void onSpinnerOpened();

        void onSpinnerClosed();

    }

    @Override
    public boolean performClick() {
        // register that the Spinner was opened so we have a status
        // indicator for the activity(which may lose focus for some other
        // reasons)
        mOpenInitiated = true;
        if (mListener != null) {
            mListener.onSpinnerOpened();
        }
        return super.performClick();
    }

    public void setSpinnerEventsListener(OnSpinnerEventsListener onSpinnerEventsListener) {
        mListener = onSpinnerEventsListener;
    }

    /**
     * Propagate the closed Spinner event to the listener from outside.
     */
    public void performClosedEvent() {
        mOpenInitiated = false;
        if (mListener != null) {
            mListener.onSpinnerClosed();
        }
    }

    /**
     * A boolean flag indicating that the Spinner triggered an open event.
     * 
     * @return true for opened Spinner
     */
    public boolean hasBeenOpened() {
        return mOpenInitiated;
    }

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        android.util.Log.d(TAG, "onWindowFocusChanged");
        super.onWindowFocusChanged(hasWindowFocus);
        if (hasBeenOpened() && hasWindowFocus) {
            android.util.Log.i(TAG, "closing popup");
            performClosedEvent();
        }
    }
}

Answer 7

Hi friends I am struggling on this issue from last two days and finally I got following solution which done my job. I tried and it worked perfectly. Thanks

 mSpinner.setOnTouchListener(new OnTouchListener(){

                @Override
                public boolean onTouch(View v, MotionEvent event) {
                   if(event.getAction() == MotionEvent.ACTION_DOWN){
                       Toast.makeText(MapActivity.this,"down",Toast.LENGTH_LONG).show();
                    // Load your spinner here
                   }
                    return false;
                }

            });

Answer 8

I think the best way to find when it got opened and closed is this way:

1. If it was closed, and now it calls "getDropDownView" in the adapter, it can be assumed that it got opened.

2. If "onItemSelected" or "onNothingSelected" are called, now it got closed.

---

EDIT: here's a sample code

public class MainActivity extends AppCompatActivity {
    boolean isSpinnerClosed = true;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        AppCompatSpinner spinner2 = (AppCompatSpinner) findViewById(R.id.spinner2);
        List<String> list = new ArrayList<String>();
        list.add("list 1");
        list.add("list 2");
        list.add("list 3");
        Log.d("AppLog", "started");
//spinner2.setondi
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list) {
            @Override
            public View getDropDownView(final int position, @Nullable final View convertView, @NonNull final ViewGroup parent) {
                if (isSpinnerClosed) {
                    Log.d("AppLog", "closed->open");
                    isSpinnerClosed = false;
                }
                return super.getDropDownView(position, convertView, parent);
            }
        };
        spinner2.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(final AdapterView<?> adapterView, final View view, final int i, final long l) {
                Log.d("AppLog", "onItemSelected");
                if (!isSpinnerClosed) {
                    Log.d("AppLog", "open->closed");
                    isSpinnerClosed = true;
                }
            }

            @Override
            public void onNothingSelected(final AdapterView<?> adapterView) {
                Log.d("AppLog", "onNothingSelected");
                if (!isSpinnerClosed) {
                    Log.d("AppLog", "open->closed");
                    isSpinnerClosed = true;
                }
            }
        });
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner2.setAdapter(dataAdapter);
    }

    @Override
    public void onWindowFocusChanged(final boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if (hasFocus && isSpinnerClosed) {
            Log.d("AppLog", "open->closed");
            isSpinnerClosed = true;
        }
    }
}