Null pointer exception at runtime.I am getting an Exception at these lines
Below I am posted the Logcat and codes related to that.
Stacktrace:
10-20 07:13:32.092: E/Buffer Error(2936): Error converting result java.lang.NullPointerException: lock == null
10-20 07:13:32.092: E/JSON Parser(2936): Error parsing data org.json.JSONException: End of input at character 0 of
10-20 07:13:32.152: W/dalvikvm(2936): threadid=11: thread exiting with uncaught exception (group=0xb3a7eba8)
10-20 07:13:32.162: E/AndroidRuntime(2936): FATAL EXCEPTION: AsyncTask #1
10-20 07:13:32.162: E/AndroidRuntime(2936): Process: com.example.androidhive, PID: 2936
10-20 07:13:32.162: E/AndroidRuntime(2936): java.lang.RuntimeException: An error occured while executing doInBackground()
10-20 07:13:32.162: E/AndroidRuntime(2936): at android.os.AsyncTask$3.done(AsyncTask.java:300)
10-20 07:13:32.162: E/AndroidRuntime(2936): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
10-20 07:13:32.162: E/AndroidRuntime(2936): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
10-20 07:13:32.162: E/AndroidRuntime(2936): at java.lang.Thread.run(Thread.java:841)
10-20 07:13:32.162: E/AndroidRuntime(2936): Caused by: java.lang.NullPointerException
10-20 07:13:32.162: E/AndroidRuntime(2936): at com.example.androidhive.AllProductsActivity$LoadAllProducts.doInBackground(AllProductsActivity.java:130)
10-20 07:13:32.162: E/AndroidRuntime(2936): at com.example.androidhive.AllProductsActivity$LoadAllProducts.doInBackground(AllProductsActivity.java:1)
10-20 07:13:32.162: E/AndroidRuntime(2936): at android.os.AsyncTask$2.call(AsyncTask.java:288)
10-20 07:13:32.162: E/AndroidRuntime(2936): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
10-20 07:13:32.162: E/AndroidRuntime(2936): ... 3 more
10-20 07:13:32.752: I/Choreographer(2936): Skipped 120 frames! The application may be doing too much work on its main thread.
10-20 07:13:33.462: I/Choreographer(2936): Skipped 63 frames! The application may be doing too much work on its main thread.
10-20 07:13:34.722: E/WindowManager(2936): android.view.WindowLeaked: Activity com.example.androidhive.AllProductsActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{b3d35370 V.E..... R.....ID 0,0-461,175} that was originally added here
10-20 07:13:34.722: E/WindowManager(2936): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:348)
10-20 07:13:34.722: E/WindowManager(2936): at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248)
10-20 07:13:34.722: E/WindowManager(2936): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.Dialog.show(Dialog.java:286)
10-20 07:13:34.722: E/WindowManager(2936): at com.example.androidhive.AllProductsActivity$LoadAllProducts.onPreExecute(AllProductsActivity.java:117)
10-20 07:13:34.722: E/WindowManager(2936): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
10-20 07:13:34.722: E/WindowManager(2936): at android.os.AsyncTask.execute(AsyncTask.java:535)
10-20 07:13:34.722: E/WindowManager(2936): at com.example.androidhive.AllProductsActivity.onCreate(AllProductsActivity.java:57)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.Activity.performCreate(Activity.java:5231)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.ActivityThread.access$800(ActivityThread.java:135)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
10-20 07:13:34.722: E/WindowManager(2936): at android.os.Handler.dispatchMessage(Handler.java:102)
10-20 07:13:34.722: E/WindowManager(2936): at android.os.Looper.loop(Looper.java:136)
10-20 07:13:34.722: E/WindowManager(2936): at android.app.ActivityThread.main(ActivityThread.java:5017)
10-20 07:13:34.722: E/WindowManager(2936): at java.lang.reflect.Method.invokeNative(Native Method)
10-20 07:13:34.722: E/WindowManager(2936): at java.lang.reflect.Method.invoke(Method.java:515)
10-20 07:13:34.722: E/WindowManager(2936): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
10-20 07:13:34.722: E/WindowManager(2936): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
10-20 07:13:34.722: E/WindowManager(2936): at dalvik.system.NativeStart.main(Native Method)
AllProductsActivity.java:
package com.example.androidhive;
public class AllProductsActivity extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
private static String url_all_products = "http://localhost/android_connect/get_all_products.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "products";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
// products JSONArray
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_products);
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute(); ---->57th line
// Get listview
ListView lv = getListView();
// on seleting single product
// launching Edit Product Screen
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String pid = ((TextView) view.findViewById(R.id.pid)).getText()
.toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
EditProductActivity.class);
// sending pid to next activity
in.putExtra(TAG_PID, pid);
// starting new activity and expecting some response back
startActivityForResult(in, 100);
}
});
}
// 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(AllProductsActivity.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show(); ---->117th line
}
/**
* 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()); ---->130th line
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
NewProductActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} 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(
AllProductsActivity.this, productsList,
R.layout.list_item, new String[] { TAG_PID,
TAG_NAME},
new int[] { R.id.pid, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
JsonParser.java:
package com.example.androidhive;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class 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 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 + "\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;
}
}
Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidhive"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="19" />
<!-- Internet Permissions -->
<uses-permission android:name="android.permission.INTERNET" />
<application
android:configChanges="keyboardHidden|orientation"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainScreenActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!-- All Product Activity -->
<activity
android:name="com.example.androidhive.AllProductsActivity"
android:label="All Products" >
</activity>
<!-- Add Product Activity -->
<activity
android:name=".NewProductActivity"
android:label="Add New Product" >
</activity>
<!-- Edit Product Activity -->
<activity
android:name=".EditProductActivity"
android:label="Edit Product" >
</activity>
</application>
</manifest>
Anybody can help me with this.Thanks in advance.
Use your ip address instead of local host.I solved this error with the help of using my ip address instead of using loc