How to set the size of an AutoCompleteTextView Result?

The best way is to create your own xml file with a customized design, such as "dropdown.xml"

<?xml version="1.0" encoding="utf-8"?>
<TextView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/textAutoComplete"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="#F3F5E1"
    android:gravity="center_vertical"
    android:padding="5dp" />

and in your code use this

AutoCompleteTextView etChoose= (AutoCompleteTextView) findViewById(R.id.etChoose);
ArrayAdapter<String> adapterChoose = new ArrayAdapter<String>(this,R.layout.dropdown, ChooseList);

Just add android:dropDownHeight="size" for AutoCompleteTextView in xml file.

private ArrayAdapter<String> autoCompleteAdapter = new ArrayAdapter<String>
                          (this,android.R.layout.simple_list_item_1, yourList) {

    public View getView(int position, View convertView, ViewGroup parent) {
        View v = super.getView(position, convertView, parent);

        ((TextView) v).setTextSize(14);                             
        Typeface Type = getFont () ;  // custom method to get a font from "assets" folder
        ((TextView) v).setTypeface(Type);               
        ((TextView) v).setTextColor(YourColor);                                             
        ((TextView) v) .setGravity(Gravity.LEFT|Gravity.CENTER_VERTICAL);

        return v;
    }           
};

 YourAutoCompleteView.setAdapter(autoCompleteAdapter);