Android NullPointerException on Screen Orientation Change

问题

I am narrowing down and explaining as simple as can, main activity initiates an async task.

When orientation change onCreate() is recalled so Async is created once gain. so in onPreExecute() i lock my orientation and in onPostExecute() i release lock on orientation. By this way if Async task has started another instance of task will never get created.

another issue has started, in main activity itself findViewById() returns null when i randomly keep changing the screen orientation. Re-producing once in 5-6 tries.

how to go on this? any help

Does onCreate() get re-called after completion of method or main thread... or is it instantaneous as soon as orientation get changed

Thank you

---------------updated

 <application
        android:allowBackup="true"
        android:icon="@drawable/ap_logo"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="agilepoint.android.mobilebpm.main.LoginActivity"
            android:configChanges="orientation"
            android:label="@string/app_name"
            android:logo="@drawable/menu_button"
            android:windowSoftInputMode="adjustPan|stateHidden" 
            >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <data android:scheme="http" />
            </intent-filter>
        </activity>
 </application>

回答1:

Found my solution...

android:configChanges="orientation" does not work with fragments

if you want to prevent runtime restarts due to orientation change when developing for API level 13 or higher (as declared by the minSdkVersion and targetSdkVersion attributes), you must include the screenSize value in addition to the orientation value. That is, you must declare android:configChanges="orientation|screenSize".

回答2:

Add android:configChanges="orientation" for that perticular activity in manifest.

来源：https://stackoverflow.com/questions/23238882/android-nullpointerexception-on-screen-orientation-change