Spinner is an android UI element; it provides a drop-down List where you can choose an item from the list.
You will need a listener to catch the selected item and do the functions you need according to the selection
Here is the setOnItemSelectedListener code
you must put this code in your onCreate method of your java class
Spinner spinner= findViewById(R.id.spinner); //initialize your spinner first
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
//this method is fired when an item is selected
String item = adapterView.getItemAtPosition(i).toString();
Toast.makeText(adapterView.getContext(),
item,
Toast.LENGTH_SHORT).show();
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});