在异步任务中将适配器设置为 listView

Question

我在如何在异步任务中为我的列表视图设置适配器时遇到问题。我有两种选择：一种是设备上有互联网，另一种是没有。如果互联网直接搜索我需要拥有的 Web 服务，而如果没有互联网，则查看我的本地数据库。第二种情况在异步任务内外都很好用。不幸的是，第一种情况，Internet，任务失败但没有退出。我留下我的代码，因为我知道我无法在异步任务中使用视图，但我的问题是，如果没有互联网，为什么它可以工作？

private class cargarListaInscripciones extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(ValidacionMultiple.this);
        pDialog.setMessage("Cargando...");
        pDialog.setCancelable(false);
        pDialog.show();
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        if (pDialog.isShowing())
            pDialog.dismiss();
    }

    @Override
    protected Void doInBackground(Void... arg0) {
        cargarVista();
        return null;
    }
}

功能：

public void cargarVista(){
      SessionManager manager = new SessionManager();
       rut_inscripcion = manager.getValue(this, "rut_inscripcion");
       nombreCliente = manager.getValue(this, "nombreCliente");
       user = manager.getValue(this, "nombreUser");
       folioEvento = manager.getValue(this, "folioEvento");
       codigoEvento = manager.getValue(this, "codigoEvento");
       seleccionValidadora = manager.getValue(this, "opcionVerificadora");
       nombreUser = manager.getValue(this, "nombreUser");
       hashUser = manager.getValue(this, "hashUsuario");
       listView = (ListView) findViewById(R.id.listView1);
       Connection cn = new Connection();
       JSONObject json = new JSONObject();
       BaseDeDatos nueva = new BaseDeDatos();
       if(cn.isNetworkAvailable(ValidacionMultiple.this) || seleccionValidadora.equals("Mixto")){
           urls = Config.URL_BASE + nombreCliente + "/"
                    + Config.URL_VALIDACION_RUT_ARRAY + nombreUser + "/"
                    + hashUser + "/" + folioEvento + "/" + rut_inscripcion;
           if (manager.getValue(ValidacionMultiple.this,"checkin") != null) {
               id_checkin = nueva.idCheckin(ValidacionMultiple.this, manager.getValue(ValidacionMultiple.this,"checkin"));
               urls = urls + id_checkin;
           }
           System.out.println(urls);
           HttpClient httpClient = new DefaultHttpClient();
           HttpPost post = new HttpPost(urls);
           post.setHeader("content-type", "application/json");
            try {
                JSONObject dato = new JSONObject();
                StringEntity entity = new StringEntity(dato.toString());
                post.setEntity(entity);
                HttpResponse resp = httpClient.execute(post);
                String respStr = EntityUtils.toString(resp.getEntity());
                JSONObject respJSON = new JSONObject(respStr);
                json = respJSON;
            } catch (Exception ex) {
                Log.e("ServicioRest", "Error!", ex);
            }
            System.out.println("JSON: " + json);
            try {
                JSONArray array = json.getJSONArray("Inscripciones");
                for (int i = 0; i < array.length(); i++) {
                    JSONObject inscripcion = (JSONObject) array.get(i);
                    RowItem item = new RowItem(inscripcion.getString("nombre"),inscripcion.getString("ticket"), inscripcion.getString("asiento") , inscripcion.getString("numero"),images[0] , Integer.parseInt(inscripcion.getString("inscripcion_id")), inscripcion.getString("hash"), Integer.parseInt(inscripcion.getString("validado")));
                    rowItems.add(item);
                }
                adapter = new CustomListViewAdapter(this,R.layout.lista_validacion_multiple, rowItems );
                //Line 141 
                listView.setAdapter(adapter);

            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
       }else{
           //Modo local o mixto.
           rowItems = nueva.getInscripcionsByRut(this, rut_inscripcion);
           adapter = new CustomListViewAdapter(this,R.layout.lista_validacion_multiple, rowItems );
           listView.setAdapter(adapter);
       }
}

网络错误：

        08-10 09:54:31.837: E/AndroidRuntime(7417): FATAL EXCEPTION: AsyncTask #1
        08-10 09:54:31.837: E/AndroidRuntime(7417): java.lang.RuntimeException: An error occured while executing doInBackground()
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.os.AsyncTask$3.done(AsyncTask.java:299)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.util.concurrent.FutureTask.run(FutureTask.java:239)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.lang.Thread.run(Thread.java:856)
        08-10 09:54:31.837: E/AndroidRuntime(7417): Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:5404)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:1076)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.view.ViewGroup.invalidateChild(ViewGroup.java:4175)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.view.View.invalidate(View.java:10894)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.view.View.invalidate(View.java:10849)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.widget.AbsListView.resetList(AbsListView.java:2290)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.widget.ListView.resetList(ListView.java:511)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.widget.ListView.setAdapter(ListView.java:451)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at com.google.zxing.client.android.ValidacionMultiple.cargarVista(ValidacionMultiple.java:141)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at com.google.zxing.client.android.ValidacionMultiple$cargarListaInscripciones.doInBackground(ValidacionMultiple.java:87)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at com.google.zxing.client.android.ValidacionMultiple$cargarListaInscripciones.doInBackground(ValidacionMultiple.java:1)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
        08-10 09:54:31.837: E/AndroidRuntime(7417):     ... 4 more

Answer 1

第一：

这条线不好。

adapter = new CustomListViewAdapter(this,R.layout.lista_validacion_multiple, rowItems );

你有这个，但应该是你的应用上下文 我不太了解你的代码，但改成这个：

adapter = new CustomListViewAdapter(ValidacionMultiple.this, R.layout.lista_validacion_multiple, rowItems );

第二个：

你必须在后执行方法中，在那个方法中你可以访问主线程。

问候。