不会出现第一个AutoCompleteTextView下拉菜单

Question

我有两个AutoCompleteTextView：

AutoCompleteTextView textViewFrom = (AutoCompleteTextView)findViewById(R.id.autoCompleteTextViewFrom);
MyAdapter myAdapter = new MyAdapter(this, android.R.layout.simple_dropdown_item_1line, Direction.FROM);
textViewFrom.setAdapter(myAdapter);

AutoCompleteTextView textViewTo = (AutoCompleteTextView)findViewById(R.id.autoCompleteTextViewTo);
MyAdapter myAdapter2 = new MyAdapter(this, android.R.layout.simple_dropdown_item_1line, Direction.TO);
textViewTo.setAdapter(myAdapter2);

为什么我只在第二个AutoCompleteTextView中显示下拉菜单？

MyAdapter类： http://pastebin.com/DwxdrTN6