更新ListAdapter动态执行过程中

本文介绍了更新ListAdapter动态执行过程中的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我想通过那个消极和积极列表之间切换的顶部用一个按钮来改变的ListView数据中期计划。 私人的ArrayList＆LT; LifeTask＆GT; positiveListData =新的ArrayList＆LT; LifeTask＆GT;（）;私人的ArrayList＆LT; LifeTask＆GT; negativeListData =新的ArrayList＆LT; LifeTask＆GT;（）;私人的ArrayList＆LT; LifeTask＆GT; currentListData = positiveListData;私人ListAdapter适配器;私人的ListView gameList; 在默认情况下我有 currentListData 指向肯定列表。在应用程序中，我有以下code的的onCreate（）功能： 适配器=新ListAdapter（这一点，R.layout.list_item，currentListData）;gameList =（ListView控件）findViewById（R.id.main_list_view）;gameList.setAdapter（适配器）; 在负按钮pressed我尝试以下操作： currentListData = negativeListData;adapter.notifyDataSetChanged（）; 但没有任何变化。我究竟做错了什么？编辑：适配器code加按要求 包cs.ucsb.cs185.dimberman.lifeRPG;进口的java.util.ArrayList;进口android.app.Activity;进口android.content.Context;进口android.view.LayoutInflater;进口android.view.View;进口android.view.ViewGroup;进口android.widget.ArrayAdapter;进口android.widget.TextView;公共类ListAdapter扩展ArrayAdapter＆LT; LifeTask＆GT; {    上下文语境;    INT layoutResourceId;    ArrayList的＆LT; LifeTask＆GT;数据= NULL;    公共ListAdapter（上下文的背景下，诠释layoutResourceId，ArrayList的＆LT; LifeTask＆GT; List_Data）{        超（背景下，layoutResourceId，List_Data）;        this.layoutResourceId = layoutResourceId;        this.context =背景;        this.data = List_Data;    }    @覆盖    公共查看getView（INT位置，查看convertView，父母的ViewGroup）{        查看排= convertView;        ItemHolder支架=无效;        如果（行== NULL）        {            LayoutInflater充气=（（活动）上下文）.getLayoutInflater（）;            行= inflater.inflate（layoutResourceId，父母，假）;            持有人=新ItemHolder（）;            holder.name =（TextView中）row.findViewById（R.id.ItemName）;            row.setTag（保持器）;        }        其他        {            支架=（ItemHolder）row.getTag（）;        }        LifeTask S = data.get（位置）;        holder.name.setText（s.getName（））;        返回行;    }    静态类ItemHolder {        TextView的名称;    }} 解决方案 我建议改变你的适配器方式如下： 公共类ListAdapter扩展ArrayAdapter＆LT; LifeTask＆GT; {    INT layoutResourceId;    公共ListAdapter（上下文的背景下，诠释layoutResourceId，ArrayList的＆LT; LifeTask＆GT; List_Data）{        超（背景下，layoutResourceId，List_Data）;        this.layoutResourceId = layoutResourceId;    }    @覆盖    公共查看getView（INT位置，查看convertView，父母的ViewGroup）{        查看排= convertView;        ItemHolder支架=无效;        如果（行== NULL）{            LayoutInflater吹气= parent.getContext（）getLayoutInflater（）。            行= inflater.inflate（layoutResourceId，父母，假）;            持有人=新ItemHolder（）;            holder.name =（TextView中）row.findViewById（R.id.ItemName）;            row.setTag（保持器）;        }其他{            支架=（ItemHolder）row.getTag（）;        }        最后LifeTask S =的getItem（位置）;        holder.name.setText（s.getName（））;        返回行;    }    静态类ItemHolder {        TextView的名称;    }} 您的实施问题是有自己的的ArrayList＆LT; LifeTask＆GT;数据。然而，它是没有必要的，因为父类 ArrayAdapter＆LT; LifeTask方式＆gt; 已经为项目的容器和使用code这样的更新列表： adapter.clear（）;adapter.addAll（negativeListData）; 明确的（）和的addAll（）将调用 notifyDataSetChanged（）。I am trying to change the ListView data mid-program by using a button at the top that switches between negative and positive lists.private ArrayList<LifeTask> positiveListData = new ArrayList<LifeTask>();private ArrayList<LifeTask> negativeListData = new ArrayList<LifeTask>();private ArrayList<LifeTask> currentListData = positiveListData;private ListAdapter adapter;private ListView gameList;By default I have currentListData pointing to the positive list. In the onCreate() function of the app I have the following code:adapter = new ListAdapter(this, R.layout.list_item, currentListData);gameList = (ListView) findViewById(R.id.main_list_view);gameList.setAdapter(adapter);When the negative button is pressed I try doing the following:currentListData = negativeListData;adapter.notifyDataSetChanged();but nothing changes. What am i doing wrong?EDIT: Adapter code added as per requestedpackage cs.ucsb.cs185.dimberman.lifeRPG;import java.util.ArrayList;import android.app.Activity;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.TextView;public class ListAdapter extends ArrayAdapter<LifeTask>{ Context context; int layoutResourceId; ArrayList<LifeTask> data = null; public ListAdapter(Context context, int layoutResourceId, ArrayList<LifeTask> List_Data) { super(context, layoutResourceId, List_Data); this.layoutResourceId = layoutResourceId; this.context = context; this.data = List_Data; } @Override public View getView(int position, View convertView, ViewGroup parent) { View row = convertView; ItemHolder holder = null; if(row == null) { LayoutInflater inflater = ((Activity)context).getLayoutInflater(); row = inflater.inflate(layoutResourceId, parent, false); holder = new ItemHolder(); holder.name = (TextView)row.findViewById(R.id.ItemName); row.setTag(holder); } else { holder = (ItemHolder)row.getTag(); } LifeTask s = data.get(position); holder.name.setText(s.getName()); return row; } static class ItemHolder{ TextView name; }} 解决方案 I would suggest to change Your adapter the following way:public class ListAdapter extends ArrayAdapter<LifeTask> { int layoutResourceId; public ListAdapter(Context context, int layoutResourceId, ArrayList<LifeTask> List_Data) { super(context, layoutResourceId, List_Data); this.layoutResourceId = layoutResourceId; } @Override public View getView(int position, View convertView, ViewGroup parent) { View row = convertView; ItemHolder holder = null; if(row == null) { LayoutInflater inflater = parent.getContext().getLayoutInflater(); row = inflater.inflate(layoutResourceId, parent, false); holder = new ItemHolder(); holder.name = (TextView)row.findViewById(R.id.ItemName); row.setTag(holder); } else { holder = (ItemHolder)row.getTag(); } final LifeTask s = getItem(position); holder.name.setText(s.getName()); return row; } static class ItemHolder{ TextView name; }}The issue with Your implementation was in having own ArrayList<LifeTask> data. However it's not needed, because parent class ArrayAdapter<LifeTask> already has container for items.And update the list using code like that:adapter.clear();adapter.addAll(negativeListData);Methods clear() and addAll() will call notifyDataSetChanged(). 这篇关于更新ListAdapter动态执行过程中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！