android - notifyDataSetChanged不起作用？

我写了以下申请书：
有一个AutoCompleteTextView字段
作为适配器，我正在使用带有listarray的arrayadapter
listarray由一些常量字符串项和一个项组成，每当用户在字段中键入某些内容时，这些项都将动态更改
我用textchangedlistener更新了最后一个列表项。但看起来，更新只发生一次。
我加了一点我的代码。也许有人能告诉我，我做错了什么。

public class HelloListView extends Activity
{
    List<String> countryList = null;
    AutoCompleteTextView textView = null;
    ArrayAdapter adapter = null;

    static String[] COUNTRIES = new String[]
    {
          "Afghanistan", "Albania", "Algeria", "American Samoa", "Andorra",
          "Yemen", "Yugoslavia", "Zambia", "Zimbabwe", ""
    };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        countryList = Arrays.asList(COUNTRIES);

        textView = (AutoCompleteTextView) findViewById(R.id.edit);
        adapter = new ArrayAdapter(this, android.R.layout.simple_dropdown_item_1line, countryList);
        adapter.notifyDataSetChanged();
        textView.setAdapter(adapter);
        textView.setThreshold(1);

        textView.addTextChangedListener(new TextWatcher()
        {

            public void onTextChanged(CharSequence s, int start, int before, int count)
            {
                countryList.set(countryList.size()-1, "User input:" + textView.getText());
            }

            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after)
            {
            }

            public void afterTextChanged(Editable s)
            {
            }
        });

        new Thread()
        {
            public void run()
            {
                // Do a bunch of slow network stuff.
                update();
            }
        }.start();
    }

    private void update()
    {
        runOnUiThread(new Runnable()
        {
            public void run()
            {
                adapter.notifyDataSetChanged();
            }
        });
    }
}

最佳答案

不要修改ArrayList。使用ArrayAdapter、add()和insert()修改remove()。您不必担心notifyDataSetChanged()。
另外，我同意mayra——考虑使用AsyncTask而不是您的thread和runOnUiThread()组合。