A.K.C.F.L
Reputation: 45
android: Force Closes
I'm new with android application development and I'm trying to develop a working application. But this page I created is giving problem since it has been created and i really hope someone can help me with this. Each time I run this program, the application force closes.
This is the source code:
public class Latest extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> eventsList;
// url to get all products list
private static String url_all_products = "http://";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_BOOKS = "books";
private static final String TAG_TITLE = "title";
private static final String TAG_AUTHOR = "author";
private static final String TAG_DESCRIPTION = "description";
private static final String TAG_PRICE = "price";
private static final String TAG_DISCOUNT = "discount";
private static final String TAG_CATEGORY = "category";
private static final String TAG_PID = "pid";
// products JSONArray
JSONArray events = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_latest);
// Hashmap for ListView
eventsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
// Get listview
// ListView lv = getListView();
}
// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(Latest.this);
pDialog.setMessage("Loading Books. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
events = json.getJSONArray(TAG_BOOKS);
// looping through All Products
for (int i = events.length()-1; i > events.length()-4; i--) {
JSONObject c = events.getJSONObject(i);
// Storing each json item in variable
String pid = c.getString(TAG_PID);
String title = c.getString(TAG_TITLE);
String author = "Author :" +c.getString(TAG_AUTHOR);
String description = c.getString(TAG_DESCRIPTION);
String price = "Price :" +c.getString(TAG_PRICE);
String discount = "Discount : " +c.getString(TAG_DISCOUNT);
String category = "Category :" +c.getString(TAG_CATEGORY);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, pid);
map.put(TAG_TITLE, title);
map.put(TAG_AUTHOR, author);
map.put(TAG_DESCRIPTION, description);
map.put(TAG_PRICE, price);
map.put(TAG_DISCOUNT, discount);
map.put(TAG_CATEGORY, category);
// adding HashList to ArrayList
eventsList.add(map);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
Latest.this, eventsList,
R.layout.list_item2, new String[] { TAG_PID, TAG_TITLE, TAG_AUTHOR, TAG_DESCRIPTION, TAG_PRICE, TAG_DISCOUNT, TAG_DESCRIPTION},
new int[] { R.id.pid, R.id.title, R.id.author,R.id.description, R.id.price, R.id.discount,R.id.category });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
and this is the LogCat(error):
Buffer Error(1024): Error converting result java.lang.NullPointerException: lock == null
JSON Parser(1024): Error parsing data org.json.JSONException: End of input at character 0 of
AndroidRuntime(1024): FATAL EXCEPTION: AsyncTask #1
AndroidRuntime(1024): java.lang.RuntimeException: An error occured while executing doInBackground()
AndroidRuntime(1024): at android.os.AsyncTask$3.done(AsyncTask.java:299)
AndroidRuntime(1024): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
AndroidRuntime(1024): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
AndroidRuntime(1024): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
AndroidRuntime(1024): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
AndroidRuntime(1024): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
AndroidRuntime(1024): at java.lang.Thread.run(Thread.java:856)
AndroidRuntime(1024): Caused by: java.lang.NullPointerException
AndroidRuntime(1024): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:113)
AndroidRuntime(1024): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:1)
AndroidRuntime(1024): at android.os.AsyncTask$2.call(AsyncTask.java:287)
AndroidRuntime(1024): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
AndroidRuntime(1024): ... 3 more
this is the JSONParser class:
public class JSONParser {
private static final String TAG = "JSONParser";
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try{
// check for request method
if(method == "POST"){
Log.d(TAG, "method=POST");
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
Log.d(TAG, "url=" + url);
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"){
Log.d(TAG, "method=GET");
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
Log.d(TAG, "url=" + url);
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
Log.d(TAG, "HTTP request done");
} catch (UnsupportedEncodingException e) {
Log.d(TAG, "UNSUPPORTED ENCODING: ", e);
} catch (ClientProtocolException e) {
Log.d(TAG, "CLIENT PROTOCOL: ", e);
} catch (IOException e) {
Log.d(TAG, "IO EXCEPTION: ", e);
}
try {
Log.d(TAG, "Extract response");
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
Log.d(TAG, "line=" + line);
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.d(TAG, "json=" + json);
} catch (Exception e) {
Log.d(TAG, "Exception: ", e);
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
Log.d(TAG, "Parse JSON");
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.d(TAG, "JSONException: ", e);
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
this is the recent logcat:
03-19 12:44:55.985: D/dalvikvm(919): GC_CONCURRENT freed 338K, 15% free 2791K/3268K, paused 111ms+119ms, total 437ms
03-19 12:45:10.246: D/dalvikvm(919): GC_CONCURRENT freed 373K, 16% free 2815K/3324K, paused 110ms+100ms, total 551ms
03-19 12:45:11.366: D/JSONParser(919): IO EXCEPTION:
03-19 12:45:11.366: D/JSONParser(919): org.apache.http.conn.HttpHostConnectException: Connection to http:// refused
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:183)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
03-19 12:45:11.366: D/JSONParser(919): at com.spyraa.bookstore.JSONParser.makeHttpRequest(JSONParser.java:66)
03-19 12:45:11.366: D/JSONParser(919): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:105)
03-19 12:45:11.366: D/JSONParser(919): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:1)
03-19 12:45:11.366: D/JSONParser(919): at android.os.AsyncTask$2.call(AsyncTask.java:287)
03-19 12:45:11.366: D/JSONParser(919): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
03-19 12:45:11.366: D/JSONParser(919): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
03-19 12:45:11.366: D/JSONParser(919): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
03-19 12:45:11.366: D/JSONParser(919): at java.lang.Thread.run(Thread.java:856)
03-19 12:45:11.366: D/JSONParser(919): Caused by: java.net.ConnectException: failed to connect to http/1 (port 80): connect failed: ECONNREFUSED (Connection refused)
03-19 12:45:11.366: D/JSONParser(919): at libcore.io.IoBridge.connect(IoBridge.java:114)
03-19 12:45:11.366: D/JSONParser(919): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
03-19 12:45:11.366: D/JSONParser(919): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
03-19 12:45:11.366: D/JSONParser(919): at java.net.Socket.connect(Socket.java:842)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
03-19 12:45:11.366: D/JSONParser(919): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
03-19 12:45:11.366: D/JSONParser(919): ... 14 more
03-19 12:45:11.366: D/JSONParser(919): Caused by: libcore.io.ErrnoException: connect failed: ECONNREFUSED (Connection refused)
03-19 12:45:11.366: D/JSONParser(919): at libcore.io.Posix.connect(Native Method)
03-19 12:45:11.366: D/JSONParser(919): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)
03-19 12:45:11.366: D/JSONParser(919): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
03-19 12:45:11.366: D/JSONParser(919): at libcore.io.IoBridge.connect(IoBridge.java:112)
03-19 12:45:11.366: D/JSONParser(919): ... 19 more
03-19 12:45:11.499: D/JSONParser(919): Extract response
03-19 12:45:12.838: D/JSONParser(919): Exception:
03-19 12:45:12.838: D/JSONParser(919): java.lang.NullPointerException: lock == null
03-19 12:45:12.838: D/JSONParser(919): at java.io.Reader.<init>(Reader.java:64)
03-19 12:45:12.838: D/JSONParser(919): at java.io.InputStreamReader.<init>(InputStreamReader.java:79)
03-19 12:45:12.838: D/JSONParser(919): at com.spyraa.bookstore.JSONParser.makeHttpRequest(JSONParser.java:83)
03-19 12:45:12.838: D/JSONParser(919): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:105)
03-19 12:45:12.838: D/JSONParser(919): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:1)
03-19 12:45:12.838: D/JSONParser(919): at android.os.AsyncTask$2.call(AsyncTask.java:287)
03-19 12:45:12.838: D/JSONParser(919): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
03-19 12:45:12.838: D/JSONParser(919): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
03-19 12:45:12.838: D/JSONParser(919): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
03-19 12:45:12.838: D/JSONParser(919): at java.lang.Thread.run(Thread.java:856)
03-19 12:45:12.985: D/JSONParser(919): Parse JSON
03-19 12:45:31.570: D/JSONParser(919): JSONException:
03-19 12:45:31.570: D/JSONParser(919): org.json.JSONException: End of input at character 0 of
03-19 12:45:31.570: D/JSONParser(919): at org.json.JSONTokener.syntaxError(JSONTokener.java:450)
03-19 12:45:31.570: D/JSONParser(919): at org.json.JSONTokener.nextValue(JSONTokener.java:97)
03-19 12:45:31.570: D/JSONParser(919): at org.json.JSONObject.<init>(JSONObject.java:154)
03-19 12:45:31.570: D/JSONParser(919): at org.json.JSONObject.<init>(JSONObject.java:171)
03-19 12:45:31.570: D/JSONParser(919): at com.spyraa.bookstore.JSONParser.makeHttpRequest(JSONParser.java:101)
03-19 12:45:31.570: D/JSONParser(919): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:105)
03-19 12:45:31.570: D/JSONParser(919): at com.spyraa.bookstore.Latest$LoadAllProducts.doInBackground(Latest.java:1)
03-19 12:45:31.570: D/JSONParser(919): at android.os.AsyncTask$2.call(AsyncTask.java:287)
03-19 12:45:31.570: D/JSONParser(919): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
03-19 12:45:31.570: D/JSONParser(919): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
03-19 12:45:31.570: D/JSONParser(919): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
03-19 12:45:31.570: D/JSONParser(919): at java.lang.Thread.run(Thread.java:856)
03-19 12:45:32.365: D/dalvikvm(919): GC_CONCURRENT freed 412K, 17% free 2798K/3352K, paused 55ms+31ms, total 671ms
besides the above, most of the logcat consists these both:
03-19 12:45:44.466: I/Choreographer(919): Skipped 289 frames! The application may be doing too much work on its main thread.
03-19 12:45:44.706: W/Trace(919): Unexpected value from nativeGetEnabledTags: 0
Upvotes: 1
Views: 686
Answers (2)
Olaf Dietsche
Reputation: 74028
Since you haven't provided line numbers, I can just guess.
Error parsing data org.json.JSONException: End of input at character 0 of
hints at an invalid JSON string. You should print the received JSON string to logcat for debugging.
Update:
The problem with JSONParser (what I have seen so far) is primarily that it catches exceptions, dumps some message and then continues. The consequence is that you usually have several messages and don't know really where it failed initially.
This is why you must add trace statements into makeHttpRequest() to see where it fails. Another (additional) approach would be to remove all try/catch statements and let the exception propagate outside. Then you will have a stack trace where the first failure is and can see what the real cause of your problem is.
But even with that, proper tracing and debugging logs are essential.
Upvotes: 1
Tim C
Reputation: 635
Sounds like mishandled JSON data. Are you sure of the structure of the JSON you're getting? A sample of that might help.
Upvotes: 0
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