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  • ListView的item选中效果

    有时app会需要点击某个item并实现选中的效果,例如做pad时用Fragment实现的左侧列表右侧内容的效果,点击左侧某一个item后会高亮选中

    有时简单的使用setSelected(boolean b)或setSelection(int position)会不成功,需要重写Adapter,并在getView中进行处理

    复制代码
    package com.example.selectitemtest;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import android.app.Activity;
    import android.content.Context;
    import android.graphics.Color;
    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.AbsListView;
    import android.widget.AdapterView;
    import android.widget.BaseAdapter;
    import android.widget.ImageView;
    import android.widget.ListView;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class MainActivity extends Activity {
        private ListView lv;
        private List<Map<String, Object>> data;
        private MyAdapter adapter;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            lv = (ListView)findViewById(R.id.lv);
            //获取将要绑定的数据设置到data中
            data = getData();
            adapter = new MyAdapter(this);
            lv.setAdapter(adapter);
            lv.setChoiceMode(AbsListView.CHOICE_MODE_SINGLE);
            lv.setOnItemClickListener(new ListView.OnItemClickListener() {
    
                @Override
                public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                        long arg3) {
                    Toast.makeText(getApplicationContext(), "click position:"+arg2, Toast.LENGTH_SHORT).show();
                    adapter.setSelectedItem(arg2);
                    //adapter.notifyDataSetInvalidated();
                }
            });
        }
         private List<Map<String, Object>> getData()
            {
                List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
                Map<String, Object> map;
                for(int i=0;i<10;i++)
                {
                    map = new HashMap<String, Object>();
                    map.put("img", R.drawable.ic_launcher);
                    map.put("title", "花郎");
                    map.put("info", "动力源于兴趣...");
                    list.add(map);
                }
                return list;
            }
            
            //ViewHolder静态类
            static class ViewHolder
            {
                public ImageView img;
                public TextView title;
                public TextView info;
            }
            
            public class MyAdapter extends BaseAdapter
            {    
                private LayoutInflater mInflater = null;
                private int selectedItem = -1;
                private MyAdapter(Context context)
                {
                    //根据context上下文加载布局,这里的是Demo17Activity本身,即this
                    this.mInflater = LayoutInflater.from(context);
                }
    
                @Override
                public int getCount() {
                    //How many items are in the data set represented by this Adapter.
                    //在此适配器中所代表的数据集中的条目数
                    return data.size();
                }
    
                @Override
                public Object getItem(int position) {
                    // Get the data item associated with the specified position in the data set.
                    //获取数据集中与指定索引对应的数据项
                    return position;
                }
                
                public void setSelectedItem(int selectedItem)
                {
                    this.selectedItem = selectedItem;
                }
    
                @Override
                public long getItemId(int position) {
                    //Get the row id associated with the specified position in the list.
                    //获取在列表中与指定索引对应的行id
                    return position;
                }
                
                //Get a View that displays the data at the specified position in the data set.
                //获取一个在数据集中指定索引的视图来显示数据
                @Override
                public View getView(int position, View convertView, ViewGroup parent) {
                    ViewHolder holder = null;
                    //如果缓存convertView为空,则需要创建View
                    if(convertView == null)
                    {
                        holder = new ViewHolder();
                        //根据自定义的Item布局加载布局
                        convertView = mInflater.inflate(R.layout.list_item, null);
                        holder.img = (ImageView)convertView.findViewById(R.id.img);
                        holder.title = (TextView)convertView.findViewById(R.id.tv);
                        holder.info = (TextView)convertView.findViewById(R.id.info);
                        //将设置好的布局保存到缓存中,并将其设置在Tag里,以便后面方便取出Tag
                        convertView.setTag(holder);
                    }else
                    {
                        holder = (ViewHolder)convertView.getTag();
                    }
                    holder.img.setBackgroundResource((Integer)data.get(position).get("img"));
                    holder.title.setText((String)data.get(position).get("title"));
                    holder.info.setText((String)data.get(position).get("info"));
                    if(position == selectedItem)
                    {
                        //convertView.setBackgroundColor(Color.BLUE);
                        //convertView.setSelected(true);
                        convertView.setBackgroundResource(R.drawable.all_listentry_left_selected);
                    }else
                    {
                        //convertView.setBackgroundColor(Color.GRAY);
                        //convertView.setSelected(false);
                        convertView.setBackgroundResource(R.drawable.lstview);
                    }
                    return convertView;
                }
                
            }
    }
    复制代码

    代码中红色标注处就是重点,lv.setChoiceMode(AbsListView.CHOICE_MODE_SINGLE);这句话必须要加

    Defines the choice behavior for the List. By default, Lists do not have any choice behavior (CHOICE_MODE_NONE). By setting the choiceMode to CHOICE_MODE_SINGLE, the List allows up to one item to be in a chosen state. By setting the choiceMode to CHOICE_MODE_MULTIPLE, the list allows any number of items to be chosen.

    实现效果如下

    转自:http://www.cnblogs.com/loulijun/archive/2013/02/17/2914122.html

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  • 原文地址:https://www.cnblogs.com/sage-blog/p/4072282.html
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