Show all items in AutocompleteTextView without writing text

You need to extend AutoCompleteTextView,

"When threshold is less than or equals 0, a threshold of 1 is applied.".

setThreshold

import android.content.Context;  
import android.graphics.Rect;
import android.util.AttributeSet;
import android.widget.AutoCompleteTextView;

public class InstantAutoComplete extends AutoCompleteTextView {

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

    public InstantAutoComplete(Context arg0, AttributeSet arg1) {
        super(arg0, arg1);
    }

    public InstantAutoComplete(Context arg0, AttributeSet arg1, int arg2) {
        super(arg0, arg1, arg2);
    }

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

    @Override
    protected void onFocusChanged(boolean focused, int direction,
            Rect previouslyFocusedRect) {
        super.onFocusChanged(focused, direction, previouslyFocusedRect);
       if (focused && getFilter()!=null) {
        performFiltering(getText(), 0);
    }
    }

}

in xml

<AutoCompleteTextView ... /> to <your.namespace.InstantAutoComplete ... />

EDIT 1

Create new class named InstantAutoComplete then put this code into the class.

In your layout xml use this class like

then find this widget in your actity (onCreate method).

Look at this example

BETTER SOLUTION HERE

You don't need to customize your AutoCompleteTextView. Instead just call autoCompleteTextView.showDropDown() Whenever you need it.....cheers :)