Android 自定义 Arrayadapter 不在 ListView 中显示数据

Question

我想要一个有高分的页面。我为布局制作了一个 row.xml，并制作了一个自定义 ArrayAdapter。当我打印出我的对象时，我得到了正确的信息，但它没有出现在我的 ListView 中。它什么也没显示。

这是我的 row.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >


    <TextView
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:id="@+id/txtNumber"
        android:layout_weight="1"
        android:layout_gravity="center_horizontal"
        android:text="@string/txtNumber" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtName"
        android:id="@+id/txtName"
        android:layout_gravity="top|bottom"
        android:layout_weight="1" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtScore"
        android:id="@+id/txtScore"
        android:layout_weight="1" />


</LinearLayout>

我的自定义数组适配器

Package be.ehb.dt.multiscreen_highscores;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.ArrayList;

// ** * Created by Naomi on 17/12/15. */

public  class PersonAdapter extends ArrayAdapter<Person> {

    public PersonAdapter(Context context, ArrayList<Person> personen) {
        super(context,0, personen);
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        Person person = getItem(position);
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.row, parent, false);
        }

        TextView txtNumber = (TextView) convertView.findViewById(R.id.txtNumber);
        TextView txtName = (TextView) convertView.findViewById(R.id.txtName);
        TextView txtScore = (TextView) convertView.findViewById(R.id.txtScore);

        txtNumber.setText(""+person.number);
        txtName.setText(person.name);
        txtScore.setText(""+person.score);
    return convertView;
    }
}

还有我的mainActivity

package be.ehb.dt.multiscreen_highscores;


import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.util.Log;
import android.widget.ListView;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity{
    private ArrayList<Person> personen;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ArrayList<Person> arrayOfPersons = new ArrayList<Person>();
        PersonAdapter adapter = new PersonAdapter(this,arrayOfPersons);
        ListView v = (ListView) findViewById(R.id.listHighscores);


        personen=new ArrayList<>();
        personen.add(new Person(1,"Naomi",3454));
        personen.add(new Person(2,"Steven",2394));
        personen.add(new Person(3, "Lieven", 2254));
        Log.d("print",personen.get(1).toString());
        v.setAdapter(adapter);

    }

}

Answer 1

你应该像这样修改你的适配器代码，

ArrayList<Person> personen;
public class PersonAdapter extends ArrayAdapter<Person> {

public PersonAdapter(Context context, ArrayList<Person> personen) {
    super(context,0, personen);
    this.personen = personen;

}

@Override
public int getCount() {
    return personen.size();
}

现在到这里 Person person = personen.get(position);

编辑:

    ListView v = (ListView) findViewById(R.id.listHighscores);
    personen=new ArrayList<>();
    personen.add(new Person(1,"Naomi",3454));
    personen.add(new Person(2,"Steven",2394));
    personen.add(new Person(3, "Lieven", 2254));
    Log.d("print",personen.get(1).toString());
    PersonAdapter adapter = new PersonAdapter(this,personen)
    v.setAdapter(adapter);