I see that you initialize "client" to null, and don't see any code that would set it to a valid object reference.
In that case, a null pointer exception on that line is perfectly valid. 03.03.2011 0:59 пользователь "Aaron Buckner" <[email protected]> написал: > I'm working on an app that uses a Web API via HttpGet and it works fine when > part of the onCreate section. > In order to make the code more portable and visible to all the activities I > thought it would be wise to create a helper class. > I copied the code to a new class and now I seem to be getting a > NullPointerException on the DefaultHttpClient.execute(HttpGet); call... > > The line in the class code that seems to cause the NPE is: > String responseBody = client.execute(get, responseHandler); > > Here is my code in the calling activity: > > MyHelper uh = new MyHelper(); > > JSONObject login = uh.queryHost(this, "user", "pass", "query"); > > Here is my class code: > > public class MyHelper { > > private static String hostURL = "http://api.host.com";; > private static String apiURL = "/v3/"; > private static String apiKey = "?key=**********"; > private ProgressDialog pDialog = null; > private DefaultHttpClient client = null; > public MyHelper() { > // TODO Auto-generated constructor stub > } > public JSONObject queryHost(Context passedContext, String username,String > password, String query){ > try { > > pDialog = ProgressDialog.show(passedContext, "Please Wait..", > "Connecting to Host",true); > > HttpGet get = new HttpGet(hostURL+apiURL+query+apiKey); > get.addHeader("Authorization", "Basic " + > getCredentials(username,password)); > > ResponseHandler<String> responseHandler = new BasicResponseHandler(); > > //I've tried both of these below with the same result > String responseBody = client.execute(get, responseHandler); > HttpResponse resp = client.execute(get); > > //JSONObject response = new JSONObject(responseBody); > //JSONObject userInfo = > response.getJSONObject("results").getJSONObject("user"); > > Log.i("Log", "Response: " + "TEST"); //response); > //Log.i("Log", "JSON: " + userInfo); > > return new JSONObject(); //response; > > } catch (Exception e) { > > //pDialog.dismiss(); > AlertDialog.Builder dialog = new AlertDialog.Builder(passedContext); > dialog.setTitle("Connection Error"); > dialog.setMessage("Unable To Connect To Host, Check Your > Username/Password & Try Again"); > dialog.setNeutralButton("Ok", null); > dialog.create().show(); > Log.e("Err", "ERROR: ", e); > > } > > return new JSONObject(); > > } > > public String getCredentials(String username, String password){ > > return (Base64.encodeBytes((username + ":" + convertToMD5(password) > ).getBytes())); > > } > > public String convertToMD5(String s){ > try { > > //Create the MD5 > MessageDigest digest = java.security.MessageDigest.getInstance("MD5"); > digest.update(s.getBytes()); > byte messageDigest[] = digest.digest(); > > //Create Hex > StringBuffer hexString = new StringBuffer(); > for (int i=0; i<messageDigest.length; i++) > hexString.append(Integer.toHexString(0xFF & messageDigest[i])); > return hexString.toString(); > > } catch (NoSuchAlgorithmException e) { > > e.printStackTrace(); > > } > > return null; > > } > > } > > Here is the NPE: > > java.lang.NullPointerException > at com.myapp.MyHelper.queryHost(MyHelper.java:48) > at com.myapp.Startup.onCreate(Startup.java:22) > at > android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) > at > android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459) > at > android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) > at android.app.ActivityThread.access$2200(ActivityThread.java:119) > at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) > at android.os.Handler.dispatchMessage(Handler.java:99) > at android.os.Looper.loop(Looper.java:123) > at android.app.ActivityThread.main(ActivityThread.java:4363) > at java.lang.reflect.Method.invokeNative(Native Method) > at java.lang.reflect.Method.invoke(Method.java:521) > at > com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) > at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) > at dalvik.system.NativeStart.main(Native Method) > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
