所以，在这种情况下，在onPostExecute方法中我使用了ListView，并且我在其中调整了一个列表适配器，以便在列表视图中显示对象（事件）。问题是适配器识别对象但它不会在ListView中显示它们。我已经看过如何使用List适配器填充一个Hashmaps数组，我确信我已经在我的代码中正确完成了它。我认为问题可能出在xml文件中。任何可以指导我正确方向的想法？
这是我的xml文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent">
</ListView>
<TextView
android:id="@+id/id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:paddingTop="6dip"
android:textSize="16sp"/>
<TextView
android:id="@+id/title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip" />
<TextView
android:id="@+id/date"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="start"/>
<TextView
android:id="@+id/time"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="start" />
<TextView
android:id="@+id/time_end"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="start" />
</LinearLayout>
.java文件：
public class EventsJSONActivity extends ListActivity {
private static String url = "http://mob.students.acg.edu/json3.php";
public static final String TAG_EVENT_INFO = "eventsinfo";
public static final String TAG_ID = "id";
public static final String TAG_TITLE = "title";
public static final String TAG_DATE = "date";
public static final String TAG_TIME = "time";
public static final String TAG_TIME_END = "time_end";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_events_json);
new GetEvents().execute();
}
class GetEvents extends AsyncTask<Void,Void,Void> {
ArrayList<HashMap<String,String>> eventList;
ProgressDialog proDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
proDialog = new ProgressDialog(EventsJSONActivity.this);
Log.d("prodialog: ","Setting Message.");
proDialog.setMessage("Please wait...");
Log.d("prodialog: ","Setting cancellable.");
proDialog.setCancelable(false);
Log.d("prodialog: ","Showing...");
proDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
WebRequest webreq = new WebRequest();
String url = "http://mob.students.acg.edu/json3.php";
String jsonStr = webreq.makeWebServiceCall(url,WebRequest.POSTRequest);
Log.d("Response: ", "> " + jsonStr);
eventList = ParseJSON(jsonStr);
Log.d("eventList info: " , eventList.toString());
return null;
}
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@Override
protected void onPostExecute(Void requestresult) {
super.onPostExecute(requestresult);
if (proDialog.isShowing()) {
proDialog.dismiss();
Log.d("prodialog: ","dismissing dialog.");
}
Log.d("Listadapter: ", "eventList: " + eventList.toString());
ListAdapter adapter = new SimpleAdapter(
EventsJSONActivity.this,eventList,
android.R.layout.simple_list_item_1,
new String[] {TAG_ID, TAG_TITLE, TAG_DATE, TAG_TIME, TAG_TIME_END},
new int[] {R.id.id,R.id.title,R.id.date,R.id.time,R.id.time_end});
Log.d("Listadapter: ","data fed");
ListView lv = (ListView)findViewById(android.R.id.list);
lv.setAdapter(adapter);
Log.d("Listadapter: ",adapter.getCount() + " items set");
}//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
private ArrayList<HashMap<String,String>> ParseJSON(String json) {
if (json != null) {
try {
ArrayList<HashMap<String,String>> eventList = new ArrayList<>();
JSONObject jsonObj = new JSONObject(json);
JSONArray events = jsonObj.getJSONArray(TAG_EVENT_INFO);
for (int i = 0; i < events.length(); i++) {
JSONObject j = events.getJSONObject(i);
String id = j.getString(TAG_ID);
String title = j.getString(TAG_TITLE);
String date = j.getString(TAG_DATE);
String time = j.getString(TAG_TIME);
String time_end = j.getString(TAG_TIME_END);
HashMap<String,String> event = new HashMap<String,String>();
event.put(TAG_ID,id);
event.put(TAG_TITLE,title);
event.put(TAG_DATE,date);
event.put(TAG_TIME,time);
event.put(TAG_TIME_END,time_end);
/*event.put(TAG_ID,"id");
event.put(TAG_TITLE,"title");
event.put(TAG_DATE,"date");
event.put(TAG_TIME,"time");
event.put(TAG_TIME_END,"time_end");*/
eventList.add(event);
}
Log.d("EventList > ", eventList.toString());
return eventList;
} catch (JSONException e) {
e.printStackTrace();
return null;
}
} else {
Log.e("ServiceHandler", "No data received from HTTP Request");
return null;
}
}
}
}
答案 0 :(得分：0)
尝试检查此处发布的解决方案... updating ListView from AsyncTask。 runOnUiThread runnable可能就是你所缺少的，因为你在这里的代码看起来是正确的。如果这不起作用，您可以尝试为listview和/或适配器创建类级别变量，并在AsyncTask的onPostExecute中修改它们。
希望这有帮助！