自定义listview无法正常工作android studio 2.3版本

Question

我想知道为什么它告诉我：“自定义列表视图已停止”吗？我该如何解决？

这是我在“主要活动”中的代码

activity_main.xml

<?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="match_parent"
    android:layoutDirection="rtl"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="customlistviews.oxbir.com.customlistview.ActivityMain">
    <EditText
        android:id="@+id/editTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/btnAdd"
        android:text="Add Row"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal" />
</LinearLayout>

ActivityMain.java

package customlistviews.oxbir.com.customlistview;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;

public class ActivityMain extends AppCompatActivity {
    Button btnAdd;
    EditText editTitle;
    ArrayList<News> newsArrayList;
    ListView listView = (ListView)findViewById(R.id.listView);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editTitle = (EditText)findViewById(R.id.editTitle);
        btnAdd = (Button)findViewById(R.id.btnAdd);
        newsArrayList = new ArrayList<>();
        final NewsAdapter newsAdapter = new NewsAdapter(ActivityMain.this, R.layout.activity_customnews, newsArrayList);
        listView.setAdapter(newsAdapter);
        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                newsArrayList.add(new News(R.drawable.newsletter, editTitle.getText().toString()));
                newsAdapter.notifyDataSetChanged();
            }
        });
    }
}

activity_customnews.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:layoutDirection="rtl">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <ImageView
            android:id="@+id/imageNews"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@drawable/newsletter" />
        <TextView
            android:id="@+id/txtTitle"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textAlignment="center"
            android:layout_gravity="center"
            android:textSize="20dp"
            android:text="Title" />
    </LinearLayout>
</LinearLayout>

News.java

package customlistviews.oxbir.com.customlistview;

public class News {
    public int imageNews;
    public String titleNews;

    public News (int imageNews, String titleNews) {
        this.imageNews = imageNews;
        this.titleNews = titleNews;
    }
}

NewsAdapter.java

package customlistviews.oxbir.com.customlistview;

import android.app.Activity;
import android.media.Image;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;

public class NewsAdapter extends ArrayAdapter {
    public int resourceID;
    public Activity activity;
    public ArrayList<News> data;

    public NewsAdapter(Activity activity, int resourceID, ArrayList<News> object) {
        super(activity, resourceID, object);

        this.resourceID = resourceID;
        this.activity = activity;
        this.data = object;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;
        view = this.activity.getLayoutInflater().inflate(this.resourceID, null);
        ImageView imageView = (ImageView) view.findViewById(R.id.imageNews);
        TextView txtTitle = (TextView) view.findViewById(R.id.txtTitle);
        News news = data.get(position);
        imageView.setImageResource(R.drawable.newsletter);
        txtTitle.setText(news.titleNews);
        return view;
    }
}

现在，我只是想在文本字段中写一些东西，每次单击按钮后，我都会在列表视图中显示照片和文本。