我的android应用程序中有一个谷歌地图，我在mysql db中保存了一些经纬度数据，我想从mysql db中读取这些数据。我已经编写了代码，但应用程序仍然是错误的。
myphp 是：
<?php
$link = mysql_connect('localhost', 'root', '') or die('Cannot connect to the DB');
mysql_select_db('joe', $link) or die('Cannot select the DB');
/* grab the posts from the db */
$query = "SELECT lattitude, longitude FROM tracking";
$result = mysql_query($query, $link) or die('Errorquery: '.$query);
$rows = array();
while ($r = mysql_fetch_assoc($result)) {
$rows[] = $r;
}
$data = "{joel:".json_encode($rows)."}";
echo $data;
?>
我有 3 个 java 活动
public class lagiiiiteslagi extends ListActivity {
private static String url = "http://10.0.2.2/labiltrack/daftartracking.php";
// JSON Node names
private static final String TAG_lattitude = "lattitude";
private static final String TAG_longitude = "longitude";
// contacts JSONArray
JSONArray lattitude = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
lattitude = json.getJSONArray(TAG_lattitude);
// looping through All Contacts
for(int i = 0; i < lattitude.length(); i++) {
JSONObject c = lattitude.getJSONObject(i);
// Storing each json item in variable
String lattitude = c.getString(TAG_lattitude);
String longitude = c.getString(TAG_longitude);
// Phone number is agin JSON Object
//JSONObject phone = c.getJSONObject(TAG_PHONE);
// creating new HashMap
HashMap<String, String> map = new HashMap<String,String>();
// adding each child node to HashMap key => value
map.put(TAG_lattitude, lattitude);
map.put(TAG_longitude, longitude);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e){
e.printStackTrace();
}
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(this, contactList,
R.layout.main,
new String[] { TAG_lattitude, TAG_longitude }, new int[] {
R.id.TextViewResult, R.id.TextViewResult1 });
setListAdapter(adapter);
// selecting single ListView item
ListView lv = getListView();
// Launching new screen on Selecting Single ListItem
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int position,
long id) {
// TODO Auto-generated method stub
// getting values from selected ListItem
//String lattitude = ((TextView)) view.findViewById(R.id.TextViewResult)).getText().toString();
//String longitude = ((TextView)) view.findViewById(R.id.TextViewResult1)).getText(lattitude).toString();
String lattitude = ((TextView) view.findViewById(R.id.TextViewResult)).getText().toString();
String longitude = ((TextView) view.findViewById(R.id.TextViewResult1)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
in.putExtra(TAG_lattitude, lattitude);
in.putExtra(TAG_longitude, longitude);
startActivity(in);
}
});
}
}
这个 JSONparser 类：
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser(){
}
public JSONObject getJSONFromUrl(String url) {
// TODO Auto-generated method stub
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}catch (UnsupportedEncodingException e){
e.printStackTrace();
}catch (ClientProtocolException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
}catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
这用于在 listview 中显示：
public class SingleMenuItemActivity extends Activity {
// JSON node keys
private static final String TAG_lattitude = "lattitude";
private static final String TAG_longitude = "longitude";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.single_list_item);
// getting intent data
Intent in = getIntent();
// Get JSON values from previous intent
String lattitude = in.getStringExtra(TAG_lattitude);
String longitude = in.getStringExtra(TAG_longitude);
// Displaying all values on the screen
TextView lbllattitude = (TextView) findViewById(R.id.listlat);
TextView lbllongitude = (TextView) findViewById(R.id.listlong);
lbllattitude.setText(lattitude);
lbllongitude.setText(longitude);
}
}
我只想在列表视图中显示纬度和经度，但仍然出错，我是 android 新手，希望有人能帮助我，在此先感谢！