Spinner: get state or get notified when opens
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();
}
}
}
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;
}
}