Référence de l'objet non définie sur une instance d'un objet lors de la tentative de remplissage de Xamarin Android TextView sur fragmentation à partir d'arrary

Question

Je reçois l'erreur System.NullReferenceException: Object reference not set to an instance of an object lorsque j'essaie de référencer un TextView de mon fragment. Cela arrive à l'exécution.

Fragment

public class Fragment1 : Fragment 
{ 
    private int checkNumber = 0; 
    private string[] updateTitleArray = new string[10]; 
    private string[] updateBodyArray = new string[10]; 
    private TextView updatesTitle0; 
    private TextView updatesTitle1; 
    private TextView updatesTitle2; 
    private TextView updatesTitle3; 
    private TextView updatesTitle4; 
    private TextView updatesTitle5; 
    private TextView updatesTitle6; 
    private TextView updatesTitle7; 
    private TextView updatesTitle8; 
    private TextView updatesTitle9; 

    private TextView updateBody0; 
    private TextView updateBody1; 
    private TextView updateBody2; 
    private TextView updateBody3; 
    private TextView updateBody4; 
    private TextView updateBody5; 
    private TextView updateBody6; 
    private TextView updateBody7; 
    private TextView updateBody8; 
    private TextView updateBody9; 



    public override void OnCreate(Bundle savedInstanceState) 
    { 
     base.OnCreate(savedInstanceState); 
     fillUpdates(updateTitleArray, updateBodyArray); 
    } 

    public static Fragment1 NewInstance() 
    { 
     var frag1 = new Fragment1 { Arguments = new Bundle() }; 
     return frag1; 
    } 


    public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
    { 
     var ignored = base.OnCreateView(inflater, container, savedInstanceState); 
     return inflater.Inflate(Resource.Layout.fragment1, null); 
    } 

    public void fillUpdates(string[] updatetitlearray, string[] updatebodyarray) 
    { 
     //increment1 so if block skips here 
     checkNumber = 1; 

     //fill updatesArray 
     updateTitleArray = updatetitlearray; 
     updateBodyArray = updatebodyarray; 

     updatesTitle0 = View.FindViewById<TextView>(Resource.Id.update_title0); 
     updatesTitle1 = View.FindViewById<TextView>(Resource.Id.update_title1); 
     updatesTitle2 = View.FindViewById<TextView>(Resource.Id.update_title2); 
     updatesTitle3 = View.FindViewById<TextView>(Resource.Id.update_title3); 
     updatesTitle4 = View.FindViewById<TextView>(Resource.Id.update_title4); 
     updatesTitle5 = View.FindViewById<TextView>(Resource.Id.update_title5); 
     updatesTitle6 = View.FindViewById<TextView>(Resource.Id.update_title6); 
     updatesTitle7 = View.FindViewById<TextView>(Resource.Id.update_title7); 
     updatesTitle8 = View.FindViewById<TextView>(Resource.Id.update_title8); 
     updatesTitle9 = View.FindViewById<TextView>(Resource.Id.update_title9); 

     updateBody0 = View.FindViewById<TextView>(Resource.Id.update_body0); 
     updateBody1 = View.FindViewById<TextView>(Resource.Id.update_body1); 
     updateBody2 = View.FindViewById<TextView>(Resource.Id.update_body2); 
     updateBody3 = View.FindViewById<TextView>(Resource.Id.update_body3); 
     updateBody4 = View.FindViewById<TextView>(Resource.Id.update_body4); 
     updateBody5 = View.FindViewById<TextView>(Resource.Id.update_body5); 
     updateBody6 = View.FindViewById<TextView>(Resource.Id.update_body6); 
     updateBody7 = View.FindViewById<TextView>(Resource.Id.update_body7); 
     updateBody8 = View.FindViewById<TextView>(Resource.Id.update_body8); 
     updateBody9 = View.FindViewById<TextView>(Resource.Id.update_body9); 


     updatesTitle0.Text = updateTitleArray[0].ToString(); 
     updatesTitle1.Text = updateTitleArray[1].ToString(); 
     updatesTitle2.Text = updateTitleArray[2].ToString(); 
     updatesTitle3.Text = updateTitleArray[3].ToString(); 
     updatesTitle4.Text = updateTitleArray[4].ToString(); 
     updatesTitle5.Text = updateTitleArray[5].ToString(); 
     updatesTitle6.Text = updateTitleArray[6].ToString(); 
     updatesTitle7.Text = updateTitleArray[7].ToString(); 
     updatesTitle8.Text = updateTitleArray[8].ToString(); 
     updatesTitle9.Text = updateTitleArray[9].ToString(); 

     updateBody0.Text = updateBodyArray[0].ToString(); 
     updateBody1.Text = updateBodyArray[1].ToString(); 
     updateBody2.Text = updateBodyArray[2].ToString(); 
     updateBody3.Text = updateBodyArray[3].ToString(); 
     updateBody4.Text = updateBodyArray[4].ToString(); 
     updateBody5.Text = updateBodyArray[5].ToString(); 
     updateBody6.Text = updateBodyArray[6].ToString(); 
     updateBody7.Text = updateBodyArray[7].ToString(); 
     updateBody8.Text = updateBodyArray[8].ToString(); 
     updateBody9.Text = updateBodyArray[9].ToString(); 
    } 
} 

Voir

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:orientation="vertical" 
     android:padding="10dp" 
     android:fillViewport="false"> 
     <LinearLayout 
      android:orientation="vertical" 
      android:layout_width="fill_parent" 
      android:layout_height="fill_parent"> 
     <!--Cardview 1--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:minHeight="60dp" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title0" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body0" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shownbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view2--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title1" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body1" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--cardview 3--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title2" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body2" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 4--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title3" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body3" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 5--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title4" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body4" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 6--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title5" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body5" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 7--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title6" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body6" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 8--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title7" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body7" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 9--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title8" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body8" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     <!--card view 10--> 
      <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       card_view:cardElevation="8dp" 
       card_view:cardCornerRadius="8dp" 
       android:layout_marginLeft="8dp" 
       android:layout_marginRight="8dp" 
       android:layout_marginTop="8dp"> 
       <GridLayout 
        android:minWidth="25px" 
        android:minHeight="25px" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:columnCount="3" 
        android:rowCount="1"> 
        <LinearLayout 
         android:orientation="vertical" 
         android:layout_gravity="fill" 
         android:layout_row="0" 
         android:layout_column="0" 
         android:padding="16sp"> 
         <TextView 
          android:id="@+id/update_title9" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update 1" 
          android:padding="4sp" 
          android:textSize="24sp" 
          android:textColor="@color/primaryText" /> 
         <TextView 
          android:id="@+id/update_body9" 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Update Details Is Shown Here" 
          android:padding="4sp" 
          android:textSize="16sp" /> 
        </LinearLayout> 
       </GridLayout> 
      </android.support.v7.widget.CardView> 
     </LinearLayout> 
    </ScrollView> 

Je comprends que ce que je suis en train de réaliser peut être mis en œuvre avec une vue recycleur mais je ne l'ai pas pleinement compris que, parce que je suis un programmeur débutant.

Answer 1

Vous appelez vous fonction trop tôt. OnCreate est appelé avant OnCreateView. Cela signifie que vos vues n'ont pas été créées lorsque vous essayez d'accéder aux composants de disposition. Vous devez déplacer votre appel de fillUpdates vers OnStart (ou OnCreateView ou une autre méthode de cycle de vie qui est appelée après OnCreateView). Jetez un oeil à la Frament Lifecycle

public override void OnStart(Bundle bundle) 
{ 
    base.OnStart(bundle); 
    fillUpdates(updateTitleArray, updateBodyArray); 
}