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POHow to make Asynctask postExecute send variable back to main class
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  1. POHow to make Asynctask postExecute send variable back to main class
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    copied!<p>I have my class called Main.java which runs the UI. I have another class called VerifyCreds.java which extends AsyncTask. VerifyCreds whole purpose is to run calls to my server on another thread so as to not lockup my UI. I don't have it sublcassed in Main.java because I will have a number of other classes that will be making calls to the server and I would like to have them all use the VerifyCreds class to do it.</p> <p>What I need to be able to do is pass data back to Main.java from VerifyCreds.java. but getting a error with the below code.</p> <p>Any help is appreciated! Thanks!</p> <p>Here is my Main.java code</p> <pre><code> package com.coolprograms.zeal; &lt;&lt;&lt;imports removed for brevity&gt;&gt; public class Main extends Activity { // Global VAR's String TAG = "ZEAL"; static Boolean authCode; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.login); //Grab elements final EditText userName = (EditText)findViewById(R.id.usernameBOX); final EditText userPWD = (EditText)findViewById(R.id.passwordBOX); final Button loginBTN = (Button)findViewById(R.id.loginBTTN); //Button listener loginBTN.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // Get username and password and add to array ArrayList&lt;String&gt; creds = new ArrayList&lt;String&gt;(); creds.add(userName.getText().toString()); creds.add(userPWD.getText().toString()); // Call method that will execute AsyncTask to get creds from server verify(creds); } }); } private void verify (ArrayList&lt;String&gt; creds) { // Start AsyncTask to get creds new VerifyCredentials(this).execute(creds); } public interface credsAuth { public void authorizedCreds(Boolean authCode); } public void verifiedCreds(Context ctx, Boolean serverAuth) { if(serverAuth = true) { // Move to next screen if we are authorized Intent i = new Intent(ctx, Items.class); startActivity(i); } } } </code></pre> <p>Here is the VerifyCreds.java code</p> <pre><code>package com.coolprograms.zeal; &lt;&lt;&lt;imports removed for brevity&gt;&gt; public class VerifyCredentials extends AsyncTask&lt;ArrayList&lt;String&gt;, Void, Boolean&gt; { private Context ctx; ProgressDialog dialog; public VerifyCredentials(Context applicationContext) { // TODO Auto-generated constructor stub ctx = applicationContext; dialog = new ProgressDialog(applicationContext); } @Override protected void onPreExecute() { dialog.setTitle("Please wait"); dialog.setMessage("Verifying username and password..."); dialog.show(); } @Override protected Boolean doInBackground(ArrayList&lt;String&gt;...creds) { //To return Boolean serverAnwser = false; //Get the creds String userID = creds[0].get(0).toString(); Log.i("ZEAL", "Creds[0]: " + creds[0].get(0).toString()); String userPWD = creds[0].get(1).toString(); Log.i("ZEAL", "Creds[1]: " + creds[0].get(1).toString()); //Get creds from server try { String serverANW = null; URL getCreds = new URL("http://XXX.XXX.XXX.XXX/api/api.php?method=getCreds&amp;id=" + userID + "&amp;pwd=" + userPWD); Log.i("ZEAL", "Webservice URL: " + getCreds.toString()); URLConnection tc = getCreds.openConnection(); BufferedReader in = new BufferedReader(new InputStreamReader( tc.getInputStream())); // Get JSON Object JSONArray jArray; jArray = new JSONArray(in.readLine()); //Log json object returned Log.i("ZEAL", jArray.toString()); //Check server response //for (int i = 0; i &lt; jArray.length(); i++) //{ JSONObject e = jArray.getJSONObject(0); String s = e.getString("RETURN"); JSONObject jObject = new JSONObject(s); serverANW = jObject.getString("RESULT"); Log.i("ZEAL", "API Result: " + serverANW); //} if(serverANW.equalsIgnoreCase("True")) { serverAnwser = true; Log.i("ZEAL", "ServerANW = " + serverANW.toString()); Log.i("ZEAL", "Setting server anwser to true"); } else { serverAnwser = false; Log.i("ZEAL", "ServerANW = " + serverANW.toString()); Log.i("ZEAL", "Setting server anwser to false - " + serverAnwser.toString()); } } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } return serverAnwser; } @Override protected void onPostExecute(final Boolean authCode) { dialog.dismiss(); // Log what the functions is doing Log.d("ZEAL","Server Response: " + authCode.toString()); Toast.makeText(ctx, "Server says: " + authCode.toString(), Toast.LENGTH_LONG).show(); Main m = new Main(); m.verifiedCreds(m, authCode); } } </code></pre> <p>ERROR:</p> <pre><code>05-23 15:18:57.190: E/AndroidRuntime(25475): FATAL EXCEPTION: main 05-23 15:18:57.190: E/AndroidRuntime(25475): java.lang.NullPointerException 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:127) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.content.ComponentName.&lt;init&gt;(ComponentName.java:75) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.content.Intent.&lt;init&gt;(Intent.java:3174) 05-23 15:18:57.190: E/AndroidRuntime(25475): at com.coolprograms.zeal.Main.verifiedCreds(Main.java:85) 05-23 15:18:57.190: E/AndroidRuntime(25475): at com.coolprograms.zeal.VerifyCredentials.onPostExecute(VerifyCredentials.java:117) 05-23 15:18:57.190: E/AndroidRuntime(25475): at com.coolprograms.zeal.VerifyCredentials.onPostExecute(VerifyCredentials.java:1) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.os.AsyncTask.finish(AsyncTask.java:602) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.os.AsyncTask.access$600(AsyncTask.java:156) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:615) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.os.Handler.dispatchMessage(Handler.java:99) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.os.Looper.loop(Looper.java:137) 05-23 15:18:57.190: E/AndroidRuntime(25475): at android.app.ActivityThread.main(ActivityThread.java:4424) 05-23 15:18:57.190: E/AndroidRuntime(25475): at java.lang.reflect.Method.invokeNative(Native Method) 05-23 15:18:57.190: E/AndroidRuntime(25475): at java.lang.reflect.Method.invoke(Method.java:511) 05-23 15:18:57.190: E/AndroidRuntime(25475): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 05-23 15:18:57.190: E/AndroidRuntime(25475): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 05-23 15:18:57.190: E/AndroidRuntime(25475): at dalvik.system.NativeStart.main(Native Method) </code></pre>
 

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