AutoCompleteTextView that limits options to just those in the adapter set for it and doesn't require two characters before the list is visible

Question

I want to use the AutoCompleteTextView to provide a list of options so when the user clicks on it they get the full list but then as they type it reduces the number of items as they search for specific items. And secondly it needs to limit the entry to just the options available in the adapter provided.

Why doesn't AutoCompleteTextView do this already? Because you have to type two characters in before the list even appears, I would like this list to be scrollable the moment the TextView has focus.

xml code :

<AutoCompleteTextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:ems="10"
        android:maxLines="1"
        android:inputType="text" />

This is what I currently have an it's susceptible to the problem I described above.

java code :

    List<String> typeList = new ArrayList<>();
    for (int i = 0; i < items.size(); i++){
        typeList.add(i, items.get(i).getName());
    }
    String[] descriptions = typeList.toArray(new String[0]);

    final ArrayAdapter<String> autoCompleteAdapter = new ArrayAdapter<String>(getContext(), android.R.layout.simple_list_item_1, names);
    final AutoCompleteTextView categoryInput = (AutoCompleteTextView) view.findViewById(R.id.autoCompleteCategory);

Alright! Managed to figure out a solution, quite simple in the end, add a OnFocusChangeListener() to the AutoCompleteTextView and then if the view has focus do showDropDown()

This way anyone who clicks it immediately gets the full list and as they type the list shrinks in size.

Answer 1

You have to override enoughToFilter() method in AutoCompleteTextView to achieve filtering happen without user entering minimum 1 or 2 characters.

Basically create your own custom view by extending AutoCompleteTextView and override enoughtToFilter() method to return true always.

public class CustomAutoCompleteTextView extends AutoCompleteTextView {

    public CustomAutoCompleteTextView(Context context) {
        super(context);
    }

    public CustomAutoCompleteTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomAutoCompleteTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public boolean enoughToFilter() {
        return true;
    }

}

Answer 2

As you written this : Because you have to type two characters in before the list even appears

If I am not understanding wrong you are looking for how to set List after typing two or more character.

you can either set it via xml android:completionThreshold="2" or you can set via programatically,

Use setThreshold().

public void setThreshold (int threshold)
Since: API Level 1
Specifies the minimum number of characters the user has to type in the edit box before the drop down list is shown.
When threshold is less than or equals 0, a threshold of 1 is applied.