title: Adding a View inside a ScrollView programmatically
body: <p>This is the xml code:</p>
  
  <pre><code>&lt;LinearLayout 
      android:id="@+id/mainLayout"
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:paddingBottom="@dimen/activity_vertical_margin"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      tools:context=".MainActivity"
      android:orientation="vertical"
      android:background="@color/black" &gt;
  
      &lt;ScrollView
          android:id="@+id/mainScrollView"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:background="@color/teal"
          android:layout_weight=".50"&gt;
  
       &lt;LinearLayout
              android:id="@+id/linearLayout1"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical" &gt;
  
       &lt;/LinearLayout&gt;
  
  
      &lt;/ScrollView&gt;
  
      &lt;Button 
           android:id="@+id/addButton"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:text="+"
           android:gravity="center"
           android:layout_weight=".20"
       /&gt;
  
       &lt;TextView
           android:id="@+id/totalHoursLabel"
           android:text="Ore Totali"
           android:background="@color/gray"
           android:textColor="@color/red"
           android:gravity="center"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:layout_weight=".10"
       /&gt;
  
       &lt;TextView
           android:id="@+id/totalHoursView"
           android:text="00:00"
           android:background="@color/white"
           android:textColor="@color/black"
           android:gravity="center"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:layout_weight=".20"
       /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>My problem is that when I try to add a view to the ScrollView or his inner LinearLayout my program crashes.</p>
  
  <p>Here is my java code:</p>
  
  <pre><code>super.onCreate(savedInstanceState);
  
  LinearLayout ll = (LinearLayout) findViewById(R.id.linearLayout1);
  
  TextView tv = new TextView(this);
  tv.setText("testView");
  tv.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
  ll.addView(tv);
  
  setContentView(R.layout.activity_main);
  </code></pre>
  
  <p>If I create a new android project this code (with only a relativeLayout and everything else empty in the xml file) works fine.</p>
  
  <p>I think that there is some problem with the findViewById method or my xml file.</p>
  
  <p>Any ideas?</p>
  
  <p>This is my LogCat file:</p>
  
  <pre><code>07-23 15:56:19.119: D/AndroidRuntime(1249): Shutting down VM
  07-23 15:56:19.119: W/dalvikvm(1249): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
  07-23 15:56:19.159: E/AndroidRuntime(1249): FATAL EXCEPTION: main
  07-23 15:56:19.159: E/AndroidRuntime(1249): java.lang.RuntimeException: Unable to start activity ComponentInfo{workTimer.worktimer/workTimer.worktimer.MainActivity}: java.lang.NullPointerException
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.os.Handler.dispatchMessage(Handler.java:99)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.os.Looper.loop(Looper.java:137)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.ActivityThread.main(ActivityThread.java:5041)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at java.lang.reflect.Method.invokeNative(Native Method)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at java.lang.reflect.Method.invoke(Method.java:511)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at dalvik.system.NativeStart.main(Native Method)
  07-23 15:56:19.159: E/AndroidRuntime(1249): Caused by: java.lang.NullPointerException
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at workTimer.worktimer.MainActivity.onCreate(MainActivity.java:32)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.Activity.performCreate(Activity.java:5104)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
  07-23 15:56:19.159: E/AndroidRuntime(1249):     ... 11 more
  07-23 15:56:22.649: I/Process(1249): Sending signal. PID: 1249 SIG: 9
  </code></pre>