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POCalling Fragment's method from host Activity
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  1. POCalling Fragment's method from host Activity
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    copied!<p>I've got a host Activity and a Fragment. In this fragment I have an update method that loads some data in an AsyncTask from the DB and updates a GridView. </p> <p>When I call this method from the host activity sometimes I get an NullPointerExeption and I don't know why...</p> <p>Here is the Activity's method which is an interface:</p> <pre><code>@Override public void onDataSetChange() { ((CalendarFragment) getSupportFragmentManager().findFragmentByTag(Constants.FRAGMENT_CALENDAR_TAG)).updateGridView(); } </code></pre> <p>And the Fragment's update method:</p> <pre><code>public void updateGridView() { // Loading the new updated data mLoadingTask = new LoadingDataTask(); mLoadingTask.execute((Void) null); } </code></pre> <p>Here is the exception in the logcat:</p> <blockquote> <p>04-17 12:05:28.366: E/AndroidRuntime(17789): FATAL EXCEPTION: main 04-17 12:05:28.366: E/AndroidRuntime(17789): java.lang.NullPointerException 04-17 12:05:28.366: E/AndroidRuntime(17789): at com.sk.neverforget.MainActivity.onDataSetChange(MainActivity.java:397) 04-17 12:05:28.366: E/AndroidRuntime(17789): at com.sk.neverforget.fragments.DiaryFragment$StoringDataTask.onPostExecute(DiaryFragment.java:543) 04-17 12:05:28.366: E/AndroidRuntime(17789): at com.sk.neverforget.fragments.DiaryFragment$StoringDataTask.onPostExecute(DiaryFragment.java:1) 04-17 12:05:28.366: E/AndroidRuntime(17789): at android.os.AsyncTask.finish(AsyncTask.java:631) 04-17 12:05:28.366: E/AndroidRuntime(17789): at android.os.AsyncTask.access$600(AsyncTask.java:177) 04-17 12:05:28.366: E/AndroidRuntime(17789): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644) 04-17 12:05:28.366: E/AndroidRuntime(17789): at android.os.Handler.dispatchMessage(Handler.java:99) 04-17 12:05:28.366: E/AndroidRuntime(17789): at android.os.Looper.loop(Looper.java:137) 04-17 12:05:28.366: E/AndroidRuntime(17789): at android.app.ActivityThread.main(ActivityThread.java:5039) 04-17 12:05:28.366: E/AndroidRuntime(17789): at java.lang.reflect.Method.invokeNative(Native Method) 04-17 12:05:28.366: E/AndroidRuntime(17789): at java.lang.reflect.Method.invoke(Method.java:511) 04-17 12:05:28.366: E/AndroidRuntime(17789): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 04-17 12:05:28.366: E/AndroidRuntime(17789): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 04-17 12:05:28.366: E/AndroidRuntime(17789): at dalvik.system.NativeStart.main(Native Method)</p> </blockquote>
 

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