使用Android中数据源的信息填充下拉列表

我试图用数据源中的用户列表填充下拉列表,我从数据库中获取这些用户列表。我为此创建了自己的布局,因为我需要一些额外的信息,如电子邮件地址以及用户的姓名和标题。我在下面粘贴的布局没有这样的内容,因为我想首先填充全名。

hcp_dropdown.xml (布局):

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/grey_98"
android:orientation="horizontal">

<android.support.constraint.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/Row_assessment_file_for_list_assessment_text_name"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="4dp"
        android:textColor="#000000"
        android:textSize="15sp"
        android:textStyle="normal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="MissingConstraints"
        tools:text="Lastname, Firstname" />

</android.support.constraint.ConstraintLayout>

我意识到我必须膨胀这个视图,所以我在适配器中这样做了。

HCPListAdapter.java (适配器):

public class HCPListAdapter extends ArrayAdapter<User> {
public HCPListAdapter(Context context, List<User> users){
    super(context, 0, users);
}

@NonNull
@Override
public View getView(int position, View convertView, @NonNull ViewGroup parent) {

    if (convertView == null) {
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.hcp_dropdown, parent, false);
    }
    HCPViewHolder viewHolder = (HCPViewHolder) convertView.getTag();

    if (viewHolder == null) {
        viewHolder = new HCPViewHolder();
        viewHolder.name = (TextView) convertView.findViewById(R.id.Row_assessment_file_for_list_assessment_text_name);

        convertView.setTag(viewHolder);
    }

    User user = getItem(position);
    if (user != null) {
        viewHolder.name.setText(user.getTitle() + ". " + user.getLastname() + ", " + user.getFirstname());
    } else {
        viewHolder.name.setText(R.string.error_unknown);
        return convertView;
    }
    return convertView;
}

    private class HCPViewHolder{
        public TextView name;
    }
}

这是我的问题 当我现在尝试使用此适配器作为微调器并用信息填充它时,它会显示第一个用户,然后当我单击下拉按钮时,它崩溃并在logcat中给我一个错误(在 RegisterActivity.java )

RegisterActivity。Java语言 (活动)

 HCPListAdapter HCPAdapter = new HCPListAdapter(RegisterActivity.this, MainActivity.sListHCPs);
        mspinnerCompleteHCP1.setAdapter(HCPAdapter);

...我在应用程序崩溃时收到以下logcat消息:

FATAL EXCEPTION: main
                                                                     Process: co.uk.mednet.mednet_ghana, PID: 8483
                                                                     android.content.res.Resources$NotFoundException: Resource ID #0x0
                                                                         at android.content.res.ResourcesImpl.getValue(ResourcesImpl.java:202)
                                                                         at android.content.res.Resources.loadXmlResourceParser(Resources.java:2970)
                                                                         at android.content.res.Resources.getLayout(Resources.java:1986)
                                                                         at android.view.LayoutInflater.inflate(LayoutInflater.java:425)
                                                                         at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:380)
                                                                         at android.widget.ArrayAdapter.getDropDownView(ArrayAdapter.java:457)
                                                                         at android.widget.Spinner$DropDownAdapter.getDropDownView(Spinner.java:1121)
                                                                         at android.widget.Spinner$DropDownAdapter.getView(Spinner.java:1117)
                                                                         at android.widget.Spinner.measureContentWidth(Spinner.java:958)
                                                                         at android.widget.Spinner$DropdownPopup.computeContentWidth(Spinner.java:1369)
                                                                         at android.widget.Spinner$DropdownPopup.show(Spinner.java:1408)
                                                                         at android.widget.Spinner.performClick(Spinner.java:869)
                                                                         at android.support.v7.widget.AppCompatSpinner.performClick(AppCompatSpinner.java:438)
                                                                         at android.view.View$PerformClick.run(View.java:23748)
                                                                         at android.os.Handler.handleCallback(Handler.java:751)
                                                                         at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                         at android.os.Looper.loop(Looper.java:154)
                                                                         at android.app.ActivityThread.main(ActivityThread.java:6776)
                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)