How to update a spinner dynamically?

Question

I've been trying to update my spinner in android dynamically but nothing I try has been working.

This is the following code I'm using to update the spinner.

typeList = dbAdapter.getList(); //array list with the values  adapter.notifyDataSetChanged(); groupSpinner.postInvalidate(); groupSpinner.setAdapter(adapter); 

The values of typeList are correct but they're not being updated in the Spinner.

Answer 1

Actually, you either have to call clear/add on the adapter, or create and set a new adapter. The adapter does not retain a reference to your list (it is only calling toArray on your list at construction), so there is no way for it to update itself.

dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, newStringList); dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinnerCategory.setAdapter(dataAdapter); 

Answer 2

You can't directly modify the original List then call notifyDataSetChanged() like on other adapters, as it doesn't hold on to the original List.

You can, however, achieve the same result using the adapter itself, like so:

spinnerAdapter.clear(); spinnerAdapter.addAll(updatedListData); spinnerAdapter.notifyDataSetChanged(); // optional, as the dataset change should trigger this by default 

Based on this answer from user392117.

edit: By default, methods that change the list like add() and remove() automatically call notifyDataSetChanged() (see Android Developer Documentation for setNotifyOnChange(boolean) )

public void setNotifyOnChange (boolean notifyOnChange)

Control whether methods that change the list (add, addAll(java.util.Collection), addAll(java.lang.Object[]), insert, remove, clear, sort(java.util.Comparator)) automatically call notifyDataSetChanged. If set to false, caller must manually call notifyDataSetChanged() to have the changes reflected in the attached view. The default is true, and calling notifyDataSetChanged() resets the flag to true.

So you should not need to call notifyDataSetChanged() every time. If you find that this is the case, you can use setNotifyOnChange(true)

spinnerAdapter.setNotifyOnChange(true); //only need to call this once spinnerAdapter.add(Object); //no need to call notifyDataSetChanged()