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这是我第一次尝试创建从远程mySQL数据库填充的ListActivity。从本地SQLite数据库获取数据时，我的工作正常。我需要修改我的课程，以便从远程数据库获取数据，所以我试图通过以下教程和文档来调整我的课程来完成此任务。由于我的观点和使用'getExtras'的复杂性，我无法弄清楚这一点。ListActivity上的空白屏幕从mySQL填充
我的问题是：现在通过修订，我得到一个空白列表，在LogCat中没有错误返回;所以你能看到我的班级有什么错？建议？
public class QueryDisplayList extends ListActivity {
private static final String PHP_KEY = "PHP_KEY";
private static final String QUERY_ORDER = "QUERY_ORDER";
JSONArray jArray;
String result = null;
InputStream is = null;
StringBuilder sb = null;
// private Object tvLabel = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle extras = getIntent().getExtras();
setContentView(R.layout.list_view2);
/**
* Get the query string from last activity and pass it to this
* activity-----------------------------------------------------
*/
// String p = null;
// if (extras != null) {
// p = extras.getString(PHP_KEY);
// }
loadQuery();
}
void loadQuery() {
new Thread(new Runnable() {
public void run() {
String qO = getIntent().getStringExtra("QUERY_ORDER");
String php = getIntent().getStringExtra("PHP_KEY");
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
// http post
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(
"http://10.0.2.2/App/php/" + php + qO + ".php");
Log.e("log_tag", "Fetched " + php + qO + ".php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
// convert response to string
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "iso-8859-1"), 8);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line = "0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
}
}).start();
setListAdapter(new QueryAdapter(this, result));
}
/**
* The Query Adaptor --------------------------------------------
*/
private class QueryAdapter extends ArrayAdapter<String> {
private Activity context;
public QueryAdapter(Activity context, String result) {
super(context, R.layout.list_view2);
this.context = context;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView = inflater.inflate(R.layout.list_item, null, true);
try {
jArray = new JSONArray(result);
JSONObject json_data = null;
for (int i = 0; i < jArray.length(); i++) {
json_data = jArray.getJSONObject(i);
final String tvLabel = json_data.getString("label");
TextView labelTxt = (TextView) convertView
.findViewById(R.id.label);
if (labelTxt != null) {
labelTxt.setText("(" + tvLabel + ")");
}
final String tvTitle = json_data.getString("title");
TextView titleTxt = (TextView) convertView
.findViewById(R.id.listTitle);
if (titleTxt != null) {
titleTxt.setText(tvTitle);
}
String tvDescription = json_data.getString("description");
TextView descriptionTxt = (TextView) convertView
.findViewById(R.id.caption);
if (descriptionTxt != null) {
descriptionTxt.setText(tvDescription);
}
String tvDate = json_data.getString("date");
TextView dateTxt = (TextView) convertView
.findViewById(R.id.dateAdded);
if (dateTxt != null) {
dateTxt.setText(tvDate);
}
String tvGoto = json_data.getString("gotoURL");
TextView gotoTxt = (TextView) convertView
.findViewById(R.id.dummy);
if (gotoTxt != null) {
gotoTxt.setText(tvGoto);
}
gotoTxt.setVisibility(View.GONE);
convertView.setTag(gotoTxt);
final String ni = json_data.getString("intent");
final ListView lv = getListView();
lv.setEnabled(true);
lv.setClickable(true);
/**
* Click Listeners --------------------------------
*/
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View v,
int arg2, long arg3) {
// -- Set the domain name in the strings.xml file
// once
// the
// DNS is established for the website.
String mDomain = getResources().getString(
R.string.domain);
String url = "";
url = mDomain + (String) v.getTag();
String intent = ni;
Class<?> nIntent = null;
try {
nIntent = Class
.forName("com.andaerosystems.andaero.utili."
+ intent);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Intent i = new Intent(QueryDisplayList.this,
nIntent);
i.putExtra("PHP_KEY", tvLabel);
i.putExtra("KEY_URL", url);
i.putExtra("KEY_SUBTITLE", tvTitle);
i.putExtra("KEY_LABEL", tvLabel);
i.putExtra("KEY_INTENT", intent);
i.putExtra("QUERY_ORDER", "ASC");
i.putExtra("KEY_YPOS", "0.0");
QueryDisplayList.this.startActivity(i);
Log.e("tag", url);
}
});
}
} catch (JSONException e1) {
Toast.makeText(getBaseContext(), "No label Found",
Toast.LENGTH_LONG).show();
} catch (ParseException e1) {
e1.printStackTrace();
}
return rowView;
}
}
}
Thnx！这是一个进步，但现在我得到了致命的例外：main 'java.lang.ClassCastException：com.andaerosystems.andaero.utili.QueryDisplayList $ 1 $ 1无法在com.andaerosystems.andaero上强制转换为android.content.Context 。 utili.QueryDisplayList $ QueryAdapter'不知道该从这里做什么..？还有什么帮助？日Thnx！ @Nikola Despotoski – CelticParser 2012-01-07 01:51:04
你正在进行一些错误的转换......检查引发异常的行 – 2012-01-07 02:16:14