title: How to programmatically add TextViews and align them in a Layout
body: <p>I want to create some TextViews (and Buttons) and than put them on the RelativeLayout within the ConstraintLayout (also could be LinearLayout or anythign else that will work)...
  My goal is to put for each button a textview left of it and them center that pait in the Layout. (Thats what I am trying to do with Layoutparams).
  But why am I getting a NullPointer Exception?</p>
  
  <p>XML Layout:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.constraint.ConstraintLayout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@+id/welcomeiqlinear"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  tools:context="com.example.william.httprequest.Welcome_InitialQuestions"&gt;
  
  &lt;TextView
      android:id="@+id/textView14"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_marginLeft="8dp"
      android:layout_marginRight="8dp"
      android:layout_marginTop="16dp"
      android:text="@string/wilkommen"
      android:textAlignment="center"
      android:textSize="35sp"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toTopOf="parent" /&gt;
  
  &lt;TextView
      android:id="@+id/textView28"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_marginLeft="8dp"
      android:layout_marginRight="8dp"
      android:layout_marginTop="24dp"
      android:text="@string/wilkommen_t1"
      android:textAlignment="center"
      app:layout_constraintHorizontal_bias="0.0"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toBottomOf="@+id/textView14" /&gt;
  
  &lt;Button
      android:id="@+id/startinitialbtn"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_marginBottom="8dp"
      android:layout_marginLeft="8dp"
      android:layout_marginRight="8dp"
      android:backgroundTint="@color/aqua"
      android:elevation="0dp"
      android:text="@string/start_btn"
      android:textColor="@color/white"
      app:layout_constraintBottom_toBottomOf="parent"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent" /&gt;
  
  &lt;RelativeLayout
      android:id="@+id/onetimerelative"
      android:layout_width="0dp"
      android:layout_height="0dp"
      android:layout_marginBottom="8dp"
      android:layout_marginEnd="8dp"
      android:layout_marginStart="8dp"
      android:layout_marginTop="8dp"
      app:layout_constraintBottom_toTopOf="@+id/startinitialbtn"
      app:layout_constraintEnd_toEndOf="parent"
      app:layout_constraintStart_toStartOf="parent"
      app:layout_constraintTop_toBottomOf="@+id/textView28"
      app:layout_constraintVertical_bias="1.0"&gt;
  
  &lt;/RelativeLayout&gt;
  
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>Java Code:</p>
  
  <pre><code>@Override
          public void onResponse(String response) {
  
              //Log.i(TAG, "MY_PROFILE_DATA: "+ response);
  
              studiesList = new LinkedList&lt;String&gt;();
  
              try {
                  JSONObject jsonObject1 = new JSONObject(response);
                  JSONArray jArray = jsonObject1.getJSONArray("data");
  
                  if (jArray != null) {
                      for (int i = 0; i &lt; jArray.length(); i++) {
                          studiesList.add(jArray.getString(i));
                      }
                  }
  
              } catch (JSONException e) {
                  e.printStackTrace();
              }
  
              Iterator&lt;String&gt; itr=studiesList.iterator();
              //Log.i(TAG,"Questionnaire_DATA: "+ studiesList.toString());
              int i = 1;
              while(itr.hasNext())
              {
                  if(i==1) {
  
                      Log.i(TAG, "Questionnaire_DATA: " + itr.next());
  
                      //add textViews
                      TextView textView = new 
                      TextView(getApplicationContext());
  
                      textView.setText("Fragebogen " + i);
  
  
                      //add buttons
                      Button button = new Button(getApplicationContext());
                      button.setText("Offen");
                      button.setId(i);
  
                      RelativeLayout.LayoutParams lp = 
                     (RelativeLayout.LayoutParams) 
                      otrelativeLayout.getLayoutParams();
                      lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT, 0);
                      lp.addRule(RelativeLayout.RIGHT_OF, button.getId());
                      lp.addRule(RelativeLayout.ALIGN_BASELINE, button.getId());
  
                      textView.setLayoutParams(lp);
  
                      otrelativeLayout.addView(button);
                      otrelativeLayout.addView(textView);
                      i++;
                  } else {
  
  
  
  
  
                  }
              }
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>FATAL EXCEPTION: main
  
  Process: com.example.william.httprequest, PID: 26073
  
  java.lang.ClassCastException: 
  android.support.constraint.ConstraintLayout$LayoutParams cannot be cast to 
  android.widget.RelativeLayout$LayoutParams
  </code></pre>
  
  <p>I really would appreciate any help :)</p>