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我的应用程序正常工作，我从适配器获取数据，但ListView只在屏幕上闪烁并返回到之前的Activity，不显示数据！ LogCat中没有显示任何错误。我已经尝试了一切！我该怎么办？我应该在哪里设置我的代码上的listView？
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Base64;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.ByteArrayInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class CaronasBuscadasListActivity extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
ListView listView;
String id_carona, _id_motorista, origem, destino, data, hora, nome;
public Bitmap imagem;
private LayoutInflater mInflater;
//JSON IDS:
private static final String TAG_SUCCESS = "success";
private static final String TAG_ID = "_id_carona";
private static final String TAG_ORIGEM = "origem_carona";
private static final String TAG_DESTINO = "destino_carona";
private static final String TAG_DATA = "data_carona";
private static final String TAG_HORA = "hora_carona";
private static final String TAG_NOME = "nome_usuario";
private static final String TAG_IMAGEM = "imagem_usuario";
private static final String TAG_MESSAGE = "mensagem";
private static final String TAG_CARONAS = "caronas";
private static final String TAG_ID_MOTORISTA = "_id_motorista";
//An array of all of our comments
private JSONArray mCaronas = null;
private CarAdapter carAdapter;
private JSONParser jsonParser = new JSONParser();
private JSONObject json;
//manages all of our comments in a list.
private ArrayList<HashMap<String, Object>> mCaronasList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_buscadas_list);
mCaronasList = new ArrayList<HashMap<String, Object>>();
listView = getListView();
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
new BuscarCarona().execute();
}
/**
* Retrieves json data of comments
*/
public void updateJSONdata(JSONObject jsonObject) {
json = jsonObject;
Log.d("JSONOOBJECT", json.toString());
//when parsing JSON stuff, we should probably
//try to catch any exceptions:
try {
mCaronas = json.getJSONArray(TAG_CARONAS);
// looping through all posts according to the json object returned
for (int i = 0; i < mCaronas.length(); i++) {
JSONObject c = mCaronas.getJSONObject(i);
//gets the content of each tag
_id_motorista = c.getString(TAG_ID_MOTORISTA);
origem = c.getString(TAG_ORIGEM);
destino = c.getString(TAG_DESTINO);
data = c.getString(TAG_DATA);
hora = c.getString(TAG_HORA);
nome = c.getString(TAG_NOME);
String image = c.getString(TAG_IMAGEM);
byte[] img = Base64.decode(image, Base64.DEFAULT);
ByteArrayInputStream img_user = new ByteArrayInputStream(img);
imagem = BitmapFactory.decodeStream(new FlushedInputStream(img_user));
HashMap<String, Object> map = new HashMap<String, Object>();
map.put(TAG_ID, _id_motorista);
map.put(TAG_ORIGEM, origem);
map.put(TAG_DESTINO, destino);
map.put(TAG_DATA, data);
map.put(TAG_HORA, hora);
map.put(TAG_NOME, nome);
map.put(TAG_IMAGEM, imagem);
mCaronasList.add(map);
Log.d("map", map.toString());
}
Log.d("mCaronasList", mCaronasList.toString());
carAdapter = new CarAdapter(this, mCaronasList);
} catch (JSONException e) {
Log.d("erro", e.toString());
e.printStackTrace();
}
}
static class FlushedInputStream extends FilterInputStream {
public FlushedInputStream(InputStream inputStream) {
super(inputStream);
}
@Override
public long skip(long n) throws IOException {
long totalBytesSkipped = 0L;
while (totalBytesSkipped < n) {
long bytesSkipped = in.skip(n - totalBytesSkipped);
if (bytesSkipped == 0L) {
int b = read();
if (b < 0) {
break; // we reached EOF
} else {
bytesSkipped = 1; // we read one byte
}
}
totalBytesSkipped += bytesSkipped;
}
return totalBytesSkipped;
}
}
class BuscarCarona extends AsyncTask<String, String, String> {
@Override
protected String doInBackground(String... args) {
int success;
String origem = getIntent().getExtras().getString("origem");
String destino = getIntent().getExtras().getString("destino");
String data = getIntent().getExtras().getString("data");
try {
List<NameValuePair> params = new ArrayList<NameValuePair>();
// Building Parameters
params.add(new BasicNameValuePair("origem", origem));
params.add(new BasicNameValuePair("destino", destino));
params.add(new BasicNameValuePair("data", data));
Log.d("request!", "starting");
//Posting user data to script
JSONObject jsonObject = jsonParser.makeHttpRequest(
POST_COMMENT_URL, "POST", params);
updateJSONdata(jsonObject);
// full json response
Log.d("Tentativa de adicionar carona!", jsonObject.toString());
// json success element
success = jsonObject.getInt(TAG_SUCCESS);
if (success == 1) {
Log.d("Carona Disponivel!", jsonObject.toString());
finish();
return jsonObject.getString(TAG_MESSAGE);
} else {
Log.d("Falha ao adicionar carona!", jsonObject.getString(TAG_MESSAGE));
return jsonObject.getString(TAG_MESSAGE);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CaronasBuscadasListActivity.this);
pDialog.setMessage("Posting Comment...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show(); }
@Override
protected void onPostExecute(String file_url) {
// dismiss the dialog once product deleted
pDialog.dismiss();
if (file_url != null) {
Toast.makeText(CaronasBuscadasListActivity.this, file_url, Toast.LENGTH_LONG).show();
}
}
}
}