Android Spinner - How To Default List Selection To None
Solution 1:
My data-sizes.xml:
<?xml version="1.0" encoding="utf-8"?><resources><string-arrayname="chunks"><item>2</item><item>4</item><item>8</item><item>16</item><item>32</item></string-array></resources>In main.xml:
<Spinner android:id="@+id/spinnerSize"android:layout_marginLeft="50px"android:layout_width="fill_parent"android:drawSelectorOnTop="true"android:layout_marginTop="5dip"android:prompt="@string/SelectSize"android:layout_marginRight="30px"android:layout_height="35px" />
In Java Code:
Spinner spinnerSize;
ArrayAdapter adapter;
...
spinnerSize = (Spinner)findViewById(R.id.spinnerSize);
adapter = ArrayAdapter.createFromResource(this, R.array.chunks, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerSize.setAdapter(adapter);
spinnerSize.setOnItemSelectedListener(newMyOnItemSelectedListener());
...
classMyOnItemSelectedListenerimplementsOnItemSelectedListener {
publicvoidonItemSelected(AdapterView<?> parent,
View view, int pos, long id) {
chunkSize = newInteger(parent.getItemAtPosition(pos).toString()).intValue();
}
publicvoidonNothingSelected(AdapterView<?> parent) {
// Dummy
}
}
So, although I can see 2 as my first default item, nothing happens unless user actually selects it.
Hope this helps!
Solution 2:
If you want, there is a decorater spinnerAdapter witch add automatically a default value :
protectedclassSpinnerAdapterWithNoValueimplementsSpinnerAdapter {
private SpinnerAdapter _current;
privatefinalstaticStringdefaultValue="Choisir";
publicSpinnerAdapterWithNoValue(SpinnerAdapter base) {
_current = base;
}
@OverridepublicintgetCount() {
return _current.getCount() + 1;
}
@Overridepublic Object getItem(int position) {
if (position == 0 || position == -1) {
returnnull;
}
return _current.getItem(position - 1);
}
@OverridepubliclonggetItemId(int position) {
if (position == 0 || position == -1) {
return -1;
}
return _current.getItemId(position - 1);
}
@OverridepublicintgetItemViewType(int position) {
if (position == 0 || position == -1) {
return -1;
}
return _current.getItemViewType(position - 1);
}
@Overridepublic View getView(int position, View convertView, ViewGroup parent) {
if (position == 0 || position == -1) {
finalTextViewv= (TextView) ((LayoutInflater) getContext().getSystemService(
Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.spinner_text, parent, false);
v.setText(defaultValue);
return v;
}
return _current.getView(position - 1, convertView, parent);
}
@OverridepublicintgetViewTypeCount() {
return _current.getViewTypeCount();
}
@OverridepublicbooleanhasStableIds() {
return _current.hasStableIds();
}
@OverridepublicbooleanisEmpty() {
return _current.isEmpty();
}
@OverridepublicvoidregisterDataSetObserver(DataSetObserver observer) {
_current.registerDataSetObserver(observer);
}
@OverridepublicvoidunregisterDataSetObserver(DataSetObserver observer) {
// TODO Auto-generated method stub
_current.unregisterDataSetObserver(observer);
}
@Overridepublic View getDropDownView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stubif (position == 0 || position == -1) {
CheckedTextViewv= (CheckedTextView) ((LayoutInflater) getContext().getSystemService(
Context.LAYOUT_INFLATER_SERVICE)).inflate(android.R.layout.simple_spinner_dropdown_item, parent,
false);
v.setText(defaultValue);
return v;
}
return _current.getDropDownView(position - 1, convertView, parent);
}
}
Then you can create your own spinner using this decorater :
publicclassSpinnerWithNoValueextendsSpinner {
publicSpinnerWithNoValue(Context context) {
super(context);
}
publicSpinnerWithNoValue(Context context, AttributeSet attrs) {
super(context, attrs);
}
publicSpinnerWithNoValue(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@OverridepublicvoidsetAdapter(SpinnerAdapter orig) {
finalSpinnerAdapteradapter=newSpinnerAdapterWithNoValue(orig);
super.setAdapter(adapter);
try {
finalMethodm= AdapterView.class.getDeclaredMethod("setNextSelectedPositionInt", int.class);
m.setAccessible(true);
m.invoke(this, -1);
finalMethodn= AdapterView.class.getDeclaredMethod("setSelectedPositionInt", int.class);
n.setAccessible(true);
n.invoke(this, -1);
} catch (Exception e) {
thrownewRuntimeException(e);
}
}
/*
* getSelectedItem renvoi null si la valeur par defaut est séléctionnée
*
* @see android.widget.AdapterView#getSelectedItem()
*/@Overridepublic Object getSelectedItem() {
returnsuper.getSelectedItem();
}
}
You just have to change the spinner declaration in your xml layout :
com.myproject.SpinnerWithNoValue
If you want, you can change the code to set the default text in the tag of your spinner.
Solution 3:
The Spinner will always have a selection. What you can do is make the Spinner display something like "Select"or "Select a option"...
To do this you can make your list options to be
actionList = {"Select", "Desactivate" }
and
publicvoidonItemSelected(AdapterView<?> arg0, View arg1, int position, long id){
actionList[0] = "Activate";
...
}
or you can do something more complicated like overrides the Spinner View or put a button instead with nothing on it and when it's clicked you create your spinner.
Solution 4:
Try setting this in xml with the prompt attribute:
android:prompt="@string/prompt"This will also fill in the top of the spinner dialog.
I overlooked this in the documentation. The prompt can not be directly applied. The prompt attribute has to be referenced from another source. Try referencing a string value.
Documentation from Android:
android:prompt
Since: API Level
The prompt to display when the spinner's dialog is shown.
Must be a reference to another resource, in the form "@[+][package:]type:name"orto a theme attribute in the form "?[package:][type:]name".
This corresponds to the global attribute resource symbol prompt.
Solution 5:
I'm just a begginner at android app development, and was facing a similar problem; was able to sort it out using a simple solution- this worked for me, hope it does for you also:
public class AdmissionActivity extends Activity implements OnItemSelectedListener{
int i;
@OverrideprotectedvoidonCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
i=0;
.........
}
........ .....
publicvoidonItemSelected(AdapterView<?> parent, View view,
int pos, long id){
if(i!=0){
//do wat you want;
}
else i=1;
}
//initially the activity will be loaded and nothing will happen (since// i=0); and then appropriate action will be taken since i would hav been// changed to sumtng else
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