I was already reading the data from my database to android. I copied the code and used it again in my other app it gave me this error.
LOGCAT:
07-08 08:52:24.422: E/Buffer Error(2636): Error converting result java.lang.NullPointerException: lock == null
07-08 08:52:24.422: E/JSON Parser(2636): Error parsing data org.json.JSONException: End of input at character 0 of
07-08 08:52:24.423: D/AndroidRuntime(2636): Shutting down VM
07-08 08:52:24.424: E/AndroidRuntime(2636): FATAL EXCEPTION: main
07-08 08:52:24.424: E/AndroidRuntime(2636): Process: com.example.purplerose, PID: 2636
07-08 08:52:24.424: E/AndroidRuntime(2636): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.purplerose/com.example.purplerose._Appetizer}: java.lang.NullPointerException: Attempt to invoke virtual method 'org.json.JSONArray org.json.JSONObject.getJSONArray(java.lang.String)' on a null object reference
PHP CODE data is already showing up
<?PHP
include_once("connection.php");
$sql = "SELECT MenuID, Name, Description2, Price FROM menu";
$result = mysqli_query($con,$sql);
$json = array();
if(mysqli_num_rows($result)){
while($row=mysqli_fetch_assoc($result)){
$json['menu'][]=$row;
}
}
mysqli_close($con);
echo json_encode($json); ?>
JSONParser
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(final String url) {
// Making HTTP request
try {
// Construct the client and the HTTP request.
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
// Execute the POST request and store the response locally.
HttpResponse httpResponse = httpClient.execute(httpPost);
// Extract data from the response.
HttpEntity httpEntity = httpResponse.getEntity();
// Open an inputStream with the data content.
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
// Create a BufferedReader to parse through the inputStream.
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
// Declare a string builder to help with the parsing.
StringBuilder sb = new StringBuilder();
// Declare a string to store the JSON object data in string form.
String line = null;
// Build the string until null.
while ((line = reader.readLine()) != null) {
sb.append(line + "
");
}
// Close the input stream.
is.close();
// Convert the string builder data to an actual string.
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// Try to 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 the JSON Object.
return jObj;
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
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 + "
");
}
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;
}}
JAVA Code
ListView mListView = (ListView) findViewById(R.id.listView1);
String url = "http://10.0.2.2/purple/readMenu.php";
try {
JSONParser jParser = new JSONParser();
JSONObject table = jParser.getJSONFromUrl(url);
JSONArray data = table.getJSONArray("menu");
//JSONArray data = new JSONArray(getJSONUrl(url));
final ArrayList<HashMap<String, String>> MyArrList = new ArrayList<HashMap<String, String>>();
HashMap<String, String> map;
for(int i = 0; i < data.length(); i++){
JSONObject c = data.getJSONObject(i);
map = new HashMap<String, String>();
map.put("MenuID", c.getString("MenuID"));
map.put("Name", c.getString("Name"));
map.put("Description2", c.getString("Description2"));
map.put("Price", c.getString("Price"));
MyArrList.add(map);
}
SimpleAdapter sAdap;
sAdap = new SimpleAdapter(_Appetizer.this, MyArrList, R.layout.menulist_arrangement,
new String[] {"Name", "Description2", "Price", "MenuID"}, new int[] {R.id.lblName, R.id.lblDesc2, R.id.lblPrice, R.id.lblMenuID});
mListView.setAdapter(sAdap);
final AlertDialog.Builder viewDetail = new AlertDialog.Builder(this);
// OnClick Item
mListView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> myAdapter, View myView,
int position, long mylng) {
String _Name = MyArrList.get(position).get("Name")
.toString();
String _Desc2 = MyArrList.get(position).get("Description2")
.toString();
String _Price = MyArrList.get(position).get("Price")
.toString();
String _MenuID = MyArrList.get(position).get("MenuID")
.toString();
//String sMemberID = ((TextView) myView.findViewById(R.id.ColMemberID)).getText().toString();
// String sName = ((TextView) myView.findViewById(R.id.ColName)).getText().toString();
// String sTel = ((TextView) myView.findViewById(R.id.ColTel)).getText().toString();
viewDetail.setIcon(android.R.drawable.btn_star_big_on);
viewDetail.setTitle(_Name);
viewDetail.setMessage("Name : " + _Name + "
"
+ "Description : " + _Desc2 + "
" + "Price : " + _Price + "
" + "ID: " + _MenuID);
viewDetail.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
viewDetail.show();
}
});
} catch (JSONException e) {
// TODO Auto-generated catch block
Log.e("Log", "Failed" +e);
e.printStackTrace();
}
Double check the JSONParser class. or my java code. i really cant tell where is the null pointer.
