Im new to Android and I need a little help. I have a class witch values from one table located on remote mysql and its working fine on 2.3 but on 4.x Im getting errors when I start it. I have read somewhere its because I`m not using AsyncTask. I tried to implement it on existing working code but there is one error, so please help because I tried everything to get this to work but no success.
Here is the existing code that works on 2.3
package com.stole.fetchtest;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.net.ParseException;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Toast;
public class FetchData extends ListActivity {
@SuppressWarnings("unchecked")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String result = null;
InputStream is = null;
StringBuilder sb = null;
ArrayList<?> nameValuePairs = new ArrayList<Object>();
List<String> r = new ArrayList<String>();
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(
"http://www.url.com/fetch.php");
httppost.setEntity(new UrlEncodedFormEntity(
(List<? extends NameValuePair>) nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
.show();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "UTF-8"));
sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
.show();
}
try {
JSONArray jArray = new JSONArray(result);
JSONObject json_data = null;
for (int i = 0; i < jArray.length(); i++) {
json_data = jArray.getJSONObject(i);
r.add(json_data.getString("names"));
}
setListAdapter(new ArrayAdapter<String>(this, R.layout.names_row, r));
} catch (JSONException e1) {
Toast.makeText(getBaseContext(), e1.toString(), Toast.LENGTH_LONG)
.show();
} catch (ParseException e1) {
Toast.makeText(getBaseContext(), e1.toString(), Toast.LENGTH_LONG)
.show();
}
}}
And then I tried to add AsyncTask, according to some tutorials found online, and it`s looking like this:
package com.stole.fetchtest;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.net.ParseException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Toast;
public class FetchData extends ListActivity {
String result = null;
InputStream is = null;
StringBuilder sb = null;
ArrayList<?> nameValuePairs = new ArrayList<Object>();
List<String> r = new ArrayList<String>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new task().execute();
}
public class task extends AsyncTask<String, String, Void> {
@SuppressWarnings("unchecked")
@Override
protected Void doInBackground(String... params) {
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.url.com/fetch.php");
httppost.setEntity(new UrlEncodedFormEntity(
(List<? extends NameValuePair>) nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.toString(),
Toast.LENGTH_LONG).show();
}
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "iso-8859-1"));
sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.toString(),
Toast.LENGTH_LONG).show();
}
return null;
}
protected void onPostExecute(Void v) {
try {
JSONArray jArray = new JSONArray(result);
JSONObject json_data = null;
for (int i = 0; i < jArray.length(); i++) {
json_data = jArray.getJSONObject(i);
r.add(json_data.getString("naziv"));
}
setListAdapter(new ArrayAdapter(this, R.layout.names_row, r));
} catch (JSONException e1) {
Toast.makeText(getBaseContext(), e1.toString(),
Toast.LENGTH_LONG).show();
} catch (ParseException e1) {
Toast.makeText(getBaseContext(), e1.toString(),
Toast.LENGTH_LONG).show();
}
}
}
}
The error I`m getting is at
setListAdapter(new ArrayAdapter(this, R.layout.names_row, r));
and it says " The constructor ArrayAdapter(FetchData.task, int, List) is undefined " Thanks!
它应该使用活动上下文而不是任务上下文。
setListAdapter(new ArrayAdapter(FetchData.this, R.layout.names_row, r));
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