Question

我有一个使用volley实现的项目，它可以正常工作，listView从mysql获取数据。但是，在数据库中更新数据时，尽管使用了notifydatasetchanged（），但在Android应用程序中却没有反映出来。我看过this并尝试实施但没有成功。这是我的代码

public class MainActivity extends  ActionBarActivity  {

private static final String TAG = MainActivity.class.getSimpleName();
private ListView listView;
private FeedListAdapter listAdapter;
private List<FeedItem> feedItems;
private String URL_FEED = "http://10.0.2.2/project/items.php";

SwipeRefreshLayout swipeLayout;

@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    listView = (ListView) findViewById(R.id.list);
    feedItems = new ArrayList<FeedItem>();
    listAdapter = new FeedListAdapter(this, feedItems);
    listView.setAdapter(listAdapter);

    GetDataTask();

swipeLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_container);

swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener()
{ @Override public void onRefresh() { 
    swipeLayout.setRefreshing(true); 
    Log.d("Swipe", "Refreshing content"); 
    ( new Handler()).postDelayed(new Runnable() { 
        @Override public void run() { 
            swipeLayout.setRefreshing(false); 

                // notify data changes to list adapater
                listAdapter.notifyDataSetChanged();


            Toast.makeText(MainActivity.this, "Refreshed", Toast.LENGTH_LONG).show();
            } }, 8000); } });

    swipeLayout.setColorScheme(android.R.color.holo_blue_bright, 
            android.R.color.holo_green_light, 
            android.R.color.holo_orange_light, 
            android.R.color.holo_red_light);
}

public void GetDataTask(){

    Cache cache = AppController.getInstance().getRequestQueue().getCache();
    Entry entry = cache.get(URL_FEED);
    if (entry != null) {
        // fetch the data from cache
        try {
            String data = new String(entry.data, "UTF-8");
            try {
                parseJsonFeed(new JSONObject(data));
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

    } else {
        // making fresh volley request and getting json
        JsonObjectRequest jsonReq = new JsonObjectRequest(Method.GET,
                URL_FEED, null, new Response.Listener<JSONObject>() {

                    @Override
                    public void onResponse(JSONObject response) {
                        VolleyLog.d(TAG, "Response: " + response.toString());
                        if (response != null) {
                            parseJsonFeed(response);
                        }
                    }
                }, new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        VolleyLog.d(TAG, "Error: " + error.getMessage());
                    }
                });

        // Adding request to volley request queue
        AppController.getInstance().addToRequestQueue(jsonReq);
    }
}

提前感谢您的帮助

Answer 1

您没有在setOnRefreshListener中调用GetDataTask函数。在通知listAdapter关于数据集更改之后，您需要调用。

这对我有用 SwipeRefreshLayout.OnRefreshListener onRefreshListener = new SwipeRefreshLayout.OnRefreshListener（）{

        @Override
        public void onRefresh() {
            swipeRefreshLayout.setRefreshing(true);
            Log.d("Swipe", "Refreshing content");

            listAdapter.notifyDataSetChanged();
            GetDataTask();

            Toast.makeText(MainActivity.this, "Refreshed", Toast.LENGTH_LONG).show();
            swipeRefreshLayout.setRefreshing(false);
        } };

如何在SwipeToFresh中使用notifyDataSetChanged

1 个答案: