Databases
StackOverflow2013
Postsdbo
POStrange NullpointerException when trying to retrieve LinearLayout
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POStrange NullpointerException when trying to retrieve LinearLayout
    primarykey
    data
    text
    <p>This is a bit of a shot in the dark, but perhaps I'm making an obvious mistake; I have a LinearLayout defined in my main.xml, with an id "@+id/imageListContainer". There is nothing else in my main.xml, and the LinearLayout is completely plain (As eclipse inserts it for you from the GUI editor).</p> <pre><code> &lt;LinearLayout android:id="@+id/imageListContainer" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"&gt; &lt;/LinearLayout&gt; </code></pre> <p>I then want to populate the LinearLayout dynamically, using this code:</p> <pre><code>LinearLayout imageContainer = (LinearLayout)findViewById(R.id.imageListContainer); </code></pre> <p>from withhin the applications onCreate() callback function.</p> <p>This used to work fine. However, as I started to add bits and pieces of code here and there (mainly in other activities), at some point it stopped working, and now I consistently get returned a nullpointer by findViewById(). I tried re-generating R.java, renaming the LinearLayout (to make sure I had control from where it was accessed; but it's only accessed from this one single place). I tried putting the code into onStart() instead, thinking that onCreate might run too early, creating a race-condition, but no luck with that either. I also made sure that the LinearLayout is indeed called "imageListContainer", which it is (otherwise the generated R.java would be wrong and javac would complain anyway) and that there is no duplicate "imageListContainer" object anywhere.</p> <p>I'm pretty much lost as to what the cause of this could be, so I'd appreciate any suggestions or guesses.</p> <p>Here is the stacktrace:</p> <pre><code>E/AndroidRuntime( 327): Uncaught handler: thread main exiting due to uncaught exception E/AndroidRuntime( 327): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.company.PictureListView/com.company.PictureListView.PictureListView.PictureListActivity}: java.lang.NullPointerException E/AndroidRuntime( 327): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496) E/AndroidRuntime( 327): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) E/AndroidRuntime( 327): at android.app.ActivityThread.access$2200(ActivityThread.java:119) E/AndroidRuntime( 327): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) E/AndroidRuntime( 327): at android.os.Handler.dispatchMessage(Handler.java:99) E/AndroidRuntime( 327): at android.os.Looper.loop(Looper.java:123) E/AndroidRuntime( 327): at android.app.ActivityThread.main(ActivityThread.java:4363) E/AndroidRuntime( 327): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime( 327): at java.lang.reflect.Method.invoke(Method.java:521) E/AndroidRuntime( 327): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) E/AndroidRuntime( 327): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) E/AndroidRuntime( 327): at dalvik.system.NativeStart.main(Native Method) E/AndroidRuntime( 327): Caused by: java.lang.NullPointerException E/AndroidRuntime( 327): at com.company.PictureListView.PictureListActivity.updateMainActivityScreen(PictureListActivity.java:50) E/AndroidRuntime( 327): at com.company.PictureListPictureListActivity.onCreate(PictureListActivity.java:38) E/AndroidRuntime( 327): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) E/AndroidRuntime( 327): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459) </code></pre> <p><strong>PS:</strong> I forgot to mention, I also called setContentView(R.layout.main), so that's not the problem either.</p> <p><strong>PSS:</strong> I tried adding a button to the GUI instead, and then calling the code containing the findViewById() inside the callback for that button, and that works! This leads me back to the idea that there might be some race-condition going on.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USAmadiro
    1. USAmadiro
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. CODid you call setContentView(R.layout.main) ? If not you have to inflate the xml layout with the LayoutInflater
      singulars
      1. POStrange NullpointerException when trying to retrieve LinearLayout
      1. USdudeldidadum
    2. COHave you called ´setContentView` in the activity?
      singulars
      1. POStrange NullpointerException when trying to retrieve LinearLayout
      1. USJarno Argillander
    3. COIs that all you got in main.xml? You might be missing `<?xml version="1.0" encoding="utf-8"?>` from the first line and `xmlns:android="http://schemas.android.com/apk/res/android"` from the LinearLayout if that is the case. If not, show us your `onCreate` and `updateMainActivityScreen`.
      singulars
      1. POStrange NullpointerException when trying to retrieve LinearLayout
      1. USJarno Argillander
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload