notifyDataSetChanged不起作用？

Question

我写下面的申请:

• 有一个AutoCompleteTextView字段
• 作为适配器我正在使用ArrayAdapter和ListArray
• 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内容时,它们将动态更改

我使用TextChangedListener来更新最后一个列表项.但似乎,更新只发生一次.

我添加了一些代码.也许有人可以告诉我,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();
            }
        });
    }
}

Answer 1

不要修改ArrayList.修改ArrayAdapter,使用add(),insert()和remove().你不用担心notifyDataSetChanged().

另外,我同意Mayra - 考虑使用AsyncTask而不是你的线程和runOnUiThread()组合.