title: Android SDK Update (revision 18) causes NullPointer Exception
body: <p>Slowly but surely I hat to update the android SDK…</p>
  
  <p>Today I update the SDK to revision 18 and my project (before the update perfectly working) throws a NullPointer Exception even I just start it up from eclipse. I’m using eclipse with the android ADT and also update this part after update the SDK. I also tried “Fix Project Properties” with no result. </p>
  
  <p>In the meanwhile my project is quit big so for the start I just post the LogCat messages, if someone need more just say it, I will post it. But I’m really disappointed that every time I update the SDK my project throws some new, mysterious errors (run into the external lib problem with revision 17…).</p>
  
  <p>Hope someone can help me out! I don’t think it’s a problem with the code anyway. Its something they changed somewhere I don’t know :/</p>
  
  <p><strong>[Update]</strong></p>
  
  <p>I get some extra time to debug the code. The problem occurs in the construtor. It look like this (suprise, suprise):</p>
  
  <pre><code>@Override
  public void onCreate(Bundle _savedInstanceState) 
  {   /// Einstiegspunkt der Android App
      super.onCreate(_savedInstanceState);       
      setContentView(R.layout.login);
      LoadSharedPreferences();
  }
  </code></pre>
  
  <p>The exception throws after the activity tries to go to the LoadSharedPrefrerences method...</p>
  
  <p><strong>[Update: Code around line 49]</strong></p>
  
  <pre><code>...
  SharedPreferences data = getSharedPreferences(_saveUserDataRef, MODE_PRIVATE);
  String tmpUsername = data.getString("username", null);
  String tmpPassword = data.getString("password", null);
  username.setText(tmpUsername);
  password.setText(tmpPassword);
  ...
  </code></pre>
  
  <p>This snippet save the username and password if you want the app to remeber these data for you. So you dont need to write it everytime you log on.</p>
  
  <p>LogCat:</p>
  
  <pre><code>04-12 12:09:47.615: D/dalvikvm(1094): GC_EXTERNAL_ALLOC freed 47K, 48% free 2835K/5379K, external 0K/0K, paused 78ms
  04-12 12:09:47.686: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$START@401462d0,-1,0,-1,0)
  04-12 12:09:47.686: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$END@4011b730,-1,0,-1,0)
  04-12 12:09:47.696: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$START@401462d0,-1,0,-1,0)
  04-12 12:09:47.696: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$END@4011b730,-1,0,-1,0)
  04-12 12:09:47.696: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$START@401462d0,-1,0,-1,0)
  04-12 12:09:47.696: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$END@4011b730,-1,0,-1,0)
  04-12 12:09:47.696: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$START@401462d0,-1,0,-1,0)
  04-12 12:09:47.696: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$END@4011b730,-1,0,-1,0)
  04-12 12:09:47.716: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$START@401462d0,-1,0,-1,0)
  04-12 12:09:47.716: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$END@4011b730,-1,0,-1,0)
  04-12 12:09:47.716: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$START@401462d0,-1,0,-1,0)
  04-12 12:09:47.716: I/[POST_RESELECT](1094): [spanChange] (o, oldStart, newStart, oldEnd, newEnd)=(android.text.Selection$END@4011b730,-1,0,-1,0)
  04-12 12:09:47.716: D/AndroidRuntime(1094): Shutting down VM
  04-12 12:09:47.716: W/dalvikvm(1094): threadid=1: thread exiting with uncaught exception (group=0x400205a0)
  04-12 12:09:47.726: E/AndroidRuntime(1094): FATAL EXCEPTION: main
  04-12 12:09:47.726: E/AndroidRuntime(1094): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.tzm.seanwesenheitsliste/de.tzm.seanwesenheitsliste.SEAnwesenheitslisteMainActivity}: java.lang.NullPointerException
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1830)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1851)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.ActivityThread.access$1500(ActivityThread.java:132)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1038)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.os.Handler.dispatchMessage(Handler.java:99)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.os.Looper.loop(Looper.java:150)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.ActivityThread.main(ActivityThread.java:4277)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at java.lang.reflect.Method.invokeNative(Native Method)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at java.lang.reflect.Method.invoke(Method.java:507)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at dalvik.system.NativeStart.main(Native Method)
  04-12 12:09:47.726: E/AndroidRuntime(1094): Caused by: java.lang.NullPointerException
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at de.tzm.seanwesenheitsliste.SEAnwesenheitslisteMainActivity.LoadSharedPreferences(SEAnwesenheitslisteMainActivity.java:49)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at de.tzm.seanwesenheitsliste.SEAnwesenheitslisteMainActivity.onCreate(SEAnwesenheitslisteMainActivity.java:32)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1794)
  04-12 12:09:47.726: E/AndroidRuntime(1094):     ... 11 more
  </code></pre>