System.NullReferenceException: Object reference not set to an instance of an object当我尝试TextView从我的片段中引用 a 时出现错误。它发生在运行时。
分段
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();
}
}
看法
<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>
我知道我想要实现的目标可以用回收器视图来实现，但我还没有完全理解，因为我是一个初学者程序员。