How to hide one item in an Android Spinner
I am looking for a way to hide one item in an Android spinner widget. This would allow you to simulate a spinner with no items selected, and ensures that the onItemSelected() callback is always called for every item selected (if the hidden item is the "current" one). Normally there is always one item in the spinner that doesn't generate a callback, namely the current one.
There is some code on stackoverflow for how to disable (gray out) items, but not how to hide items completely as if they don't exist.
After much experimentation I've come up with a somewhat hack-ish solution that works on various old and new Android platforms. It has some minor cosmetic drawbacks which are hard to notice. I'd still like to hear of a more official solution, other than "don't do that with a spinner".
This always hides the first item in the spinner, but could fairly easily be extended to hide an arbitrary item or more than one item. Add a dummy item containing an empty string at the start of your list of spinner items. You may want to set the current spinner selection to item 0 before the spinner dialog opens, this will simulate an unselected spinner.
Spinner setup example with ArrayAdapter method override:
List<String> list = new ArrayList<String>();
list.add(""); // Initial dummy entry
list.add("string1");
list.add("string2");
list.add("string3");
// Populate the spinner using a customized ArrayAdapter that hides the first (dummy) entry
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list) {
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent)
{
View v = null;
// If this is the initial dummy entry, make it hidden
if (position == 0) {
TextView tv = new TextView(getContext());
tv.setHeight(0);
tv.setVisibility(View.GONE);
v = tv;
}
else {
// Pass convertView as null to prevent reuse of special case views
v = super.getDropDownView(position, null, parent);
}
// Hide scroll bar because it appears sometimes unnecessarily, this does not prevent scrolling
parent.setVerticalScrollBarEnabled(false);
return v;
}
};
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mySpinner.setAdapter(dataAdapter);
To hide an arbitrary item or more than one item I think that you can implement your own adapter and set the index (or array list of indexes) that you want to hide.
public class CustomAdapter extends ArrayAdapter<String> {
private int hidingItemIndex;
public CustomAdapter(Context context, int textViewResourceId, String[] objects, int hidingItemIndex) {
super(context, textViewResourceId, objects);
this.hidingItemIndex = hidingItemIndex;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
View v = null;
if (position == hidingItemIndex) {
TextView tv = new TextView(getContext());
tv.setVisibility(View.GONE);
v = tv;
} else {
v = super.getDropDownView(position, null, parent);
}
return v;
}
}
And use your custom adapter when you create the list of items.
List<String> list = new ArrayList<String>();
list.add(""); // Initial dummy entry
list.add("string1");
list.add("string2");
list.add("string3");
int hidingItemIndex = 0;
CustomAdapter dataAdapter = new CustomAdapter(this, android.R.layout.simple_spinner_item, list, hidingItemIndex);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mySpinner.setAdapter(dataAdapter);
(I have not tested the code) hope that helps.
It's easier to hide an item at the end of the list by truncating the list.
But you have to select it first so it appears in the spinner, and then check if the selection has been changed to one of the items displayed.
List<String> list = new ArrayList<String>();
list.add("string1");
list.add("string2");
list.add("string3");
list.add("[Select one]");
final int listsize = list.size() - 1;
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, list) {
@Override
public int getCount() {
return(listsize); // Truncate the list
}
};
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mySpinner.setAdapter(dataAdapter);
mySpinner.setSelection(listsize); // Hidden item to appear in the spinner
To hide any item in the spinner dropdown you need to pass the position of item which needs to hided based on criteria required. I have achieved this in a use case of hiding the item which is selected from dropdown
public class CustomAdapter extends ArrayAdapter<String> {
private List<String> dates;
private int hideItemPostion;
public CustomAdapter (Context context, int resource, List<String> dates) {
super(context, resource,dates);
this.dates=dates;
}
public void setItemToHide(int itemToHide)
{
this.hideItemPostion =itemToHide;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
View v = null;
if (position == hideItemPostion) {
TextView tv = new TextView(getContext());
tv.setVisibility(View.GONE);
tv.setHeight(0);
v = tv;
v.setVisibility(View.GONE);
}
else
v = super.getDropDownView(position, null, parent);
return v;
}}
And setting the adapter is something like this
final CustomAdapter dataAdapter = new CustomAdapter(this,R.layout.spinner_item,dates);
dataAdapter.setDropDownViewResource(R.layout.spinner_dropdown_item);
spinner.setAdapter(dataAdapter);
dataAdapter.setItemToHide(0);
On selecting some items from the dropdown also the position needs to changed
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, final int i, long l) {
dataAdapter.notifyDataSetChanged();
mEPGDateSelector.setSelection(i);
dataAdapter.setItemToHide(i);}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});