Java 调用notifyDataSetChanged后Android ListView未更新

我有一项活动，我是这样开始的：

public class MyProblemsActivity extends ListActivity 
{
    String[] PROBLEMS = new String[] {"One", "Two", "Three" };
    ArrayAdapter adapter;       

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

        adapter = new ArrayAdapter<String>(this,R.layout.my_problems, PROBLEMS);

        setListAdapter(adapter);

        ListView lv = getListView();
        lv.setTextFilterEnabled(true);

@Override
protected void onPostExecute(String result) 
{       
    PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
    adapter.clear();
    adapter.addAll(PROBLEMS);
    adapter.notifyDataSetChanged();
}

@Override
protected void onPostExecute(String result) 
{                  

  runOnUiThread(new Runnable() {

    @Override
    public void run() {
            PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
            adapter.notifyDataSetChanged();
    }
});
};

但屏幕不会更新。我在这里做错了什么？如何让屏幕用新值更新

谢谢

现在正在发生的事情

PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };

问题

正在获取对

新的

字符串数组对象的引用…因此旧引用保持原样（未更改）

要更正它，请使用以下命令：

PROBLEMS.clear();
List<String> newlist = new ArrayList<String>();
newlist.add(..);
..
PROBLEMS.addAll(newlist);
adapter.notifyDataSetChanged();

PROBLEMS.clear（）；
List newlist=newarraylist（）；
newlist.add（…）；
..
PROBLEMS.addAll（newlist）；
adapter.notifyDataSetChanged（）；

这样，新字符串将只添加到问题指出的现有数组引用中

---

注意：我已经提到使用arraylist of string而不是string[]，要使用它的clear（）、addAll（）功能，您可以根据自己的使用修改string[]的功能。

如果您想要一个更简单的答案，您只需将代码更改为如下所示：

public class MyProblemsActivity extends ListActivity 
{
    String[] PROBLEMS = new String[] {"One", "Two", "Three" };
    ArrayAdapter adapter;       

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

        adapter = new ArrayAdapter<String>(this,R.layout.my_problems, PROBLEMS);

        setListAdapter(adapter);

        ListView lv = getListView();
        lv.setTextFilterEnabled(true);

@Override
protected void onPostExecute(String result) 
{       
    PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
    adapter.clear();
    adapter.addAll(PROBLEMS);
    adapter.notifyDataSetChanged();
}

@Override
protected void onPostExecute(String result) 
{                  

  runOnUiThread(new Runnable() {

    @Override
    public void run() {
            PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
            adapter.notifyDataSetChanged();
    }
});
};

---

这将更改ArrayAdapter的内容，使其包含新字符串[]中的字符串，然后通知ListView ArrayAdapter包含新内容。这将导致ListView更新并显示您的新字符串。

我听说您通过异步回调更新了列表。我的情况也是如此。我去了在UI线程中运行它，突然它像预期的那样工作了（如果不这样做，通常会出现异常。在这里，它只是不刷新列表。）在我看来，其他答案只是解决办法

因此，如下更改代码：

public class MyProblemsActivity extends ListActivity 
{
    String[] PROBLEMS = new String[] {"One", "Two", "Three" };
    ArrayAdapter adapter;       

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

        adapter = new ArrayAdapter<String>(this,R.layout.my_problems, PROBLEMS);

        setListAdapter(adapter);

        ListView lv = getListView();
        lv.setTextFilterEnabled(true);

@Override
protected void onPostExecute(String result) 
{       
    PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
    adapter.clear();
    adapter.addAll(PROBLEMS);
    adapter.notifyDataSetChanged();
}

@Override
protected void onPostExecute(String result) 
{                  

  runOnUiThread(new Runnable() {

    @Override
    public void run() {
            PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
            adapter.notifyDataSetChanged();
    }
});
};