Question

我的测试应用程序包含一个ListActivity，用于填充Contacts中的内容。 LogCat的错误没有解释异常的来源，因为没有涉及项目文件。

如果在ADV或设备上运行（测试了两部不同的手机），它会意外停止。

重要说明：当用户滚动列表以查看更多项目时，会发生错误：当显示两到三个项目时。（始终在列表中的同一点崩溃，并且两者：用手指或轨迹球滚动）。

进一步调查的最佳方式是什么？

10-13 13:21:00.662: E/AndroidRuntime(8031): FATAL EXCEPTION: main
10-13 13:21:00.662: E/AndroidRuntime(8031): java.lang.NullPointerException
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.widget.AbsListView.obtainView(AbsListView.java:1304)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.widget.ListView.makeAndAddView(ListView.java:1727)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.widget.ListView.fillDown(ListView.java:652)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.widget.ListView.fillGap(ListView.java:623)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.widget.AbsListView.trackMotionScroll(AbsListView.java:2944)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.widget.AbsListView$FlingRunnable.run(AbsListView.java:2485)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.os.Handler.handleCallback(Handler.java:587)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.os.Handler.dispatchMessage(Handler.java:92)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.os.Looper.loop(Looper.java:123)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at android.app.ActivityThread.main(ActivityThread.java:4627)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at java.lang.reflect.Method.invokeNative(Native Method)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at java.lang.reflect.Method.invoke(Method.java:521)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
10-13 13:21:00.662: E/AndroidRuntime(8031):     at dalvik.system.NativeStart.main(Native Method)

更新：适配器的代码：

package com.stripedbee.warayu;

import java.util.List;

import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class ContactAdapter extends ArrayAdapter<Contact> {

    private final List<Contact> _contacts;
    private final Activity _context;

    public ContactAdapter(Activity context, List<Contact> contacts) {
        super(context, R.layout.contact_list_item, contacts);
        this._contacts = contacts;
        this._context = context;
    }

    static class ViewHolder {
        protected TextView display_name;
        protected TextView number;
        protected TextView number_type;
        private Contact contact;

        protected void setContact(Contact contact) {
            this.display_name.setText(contact.get_display_name());
            this.number.setText(contact.get_number());
            this.number_type.setText(contact.get_number_type());
            this.contact = contact;
        }

        protected Contact getContact() {
            return contact;
        }
    }

    @Override
    public Contact getItem(int position) {
        return this._contacts.get(position);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = null;
        if (convertView == null) {
            LayoutInflater inflater = this._context.getLayoutInflater();
            view = inflater.inflate(R.layout.contact_list_item, null);
            final ViewHolder viewHolder = new ViewHolder();
            viewHolder.display_name = (TextView) view
                    .findViewById(R.id.txtDisplayName);
            viewHolder.number = (TextView) view.findViewById(R.id.txtNumber);
            viewHolder.number_type = (TextView) view
                    .findViewById(R.id.txtNumberType);
            viewHolder.setContact(_contacts.get(position));
            view.setTag(viewHolder);
        }

        return view;
    }
}

Answer 1

当null不是getView时（例如，当用户开始滚动时），您会从convertView方法返回null视图。您的getView方法应该是这样的：

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View view = null;
    ViewHolder holder;
    if (convertView == null) {
        LayoutInflater inflater = this._context.getLayoutInflater();
        view = inflater.inflate(R.layout.contact_list_item, parent, false);
        holder = new ViewHolder();
        viewHolder.display_name = (TextView) view
                .findViewById(R.id.txtDisplayName);
        viewHolder.number = (TextView) view.findViewById(R.id.txtNumber);
        viewHolder.number_type = (TextView) view
                .findViewById(R.id.txtNumberType);            
        view.setTag(viewHolder);
    } else {
        view = convertView;
        holder = (ViewHolder) view.getTag();
    }        
    holder.setContact(_contacts.get(position));
    return view;
}

Android：应用程序意外停止（进一步调查的最佳方法是什么？）

1 个答案: