自定义ArrayAdapter

相关类

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import android.content.Context;

import android.widget.ListView;
import android.widget.ArrayAdapter;

import java.util.List;
import java.util.ArrayList;

• 从ArrayAdapter派生类，并实现getView()方法
• getItem()方法需要返回一个对象，以便在处理事件响应时，父类的ListView能够获取到Item对象类型
• 通过notifyDataSetChanged()通知更新列表内容

ArrayAdapter派生类

public class MyArrayAdapter extends BaseAdapter {

    LayoutInflater factory; 
    List<MyListItem> mListItem;
    Context mContext;

    public MyArrayAdapter(Context context, List<MyListItem> listItems) {

        mListItem = listItems;
        mContext = context;
        factory = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        // 返回列表的大小
        return mListItem.size();
    }

    @Override
    public Object getItem(int position) {
        // 如果此处返回null，在处理OnItemClick事件时会产生空指针异常
        return mListItem.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;

        if ( view == null ) {
            // 从XML中获取Item布局视图
            view = factory.inflate(R.layout.item, null);
        }

        // 按位置获取item
        MyListItem item = getItem(position);
        // 为布局控件设置文本
        TextView textView = (TextView) view.findViewById(R.id.itemtext);
        textView.setText(item.getName());
        
        // notifyDataSetChanged()方法通知刷新列表内容，可以通过某些标志位做特别的刷新处理
        if (something) {
            // ......
        } else {
            // ......
        }

        return view;
    }
}

自定义Item类

public class MyListItem {
    String mItemName;

    public MyListItem(String itemName) {
        mItemName = itemName;    
    }

    public String getName() {
        return mItemName;
    }
}

添加事件监听

private OnItemClickListener cRecentFileItemClicked = new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
            long id) {
        ListView listView = (ListView) parent;

        MyListItem item = (MyListItem) listView
                .getItemAtPosition(position);
    }
};

在Activity中使用自定义ArrayAdapter

public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ListView listView = (ListView) findViewById(R.id.listview);

    List<MyListItem> list = new ArrayList<MyListItem>();
    MyListItem item1 = new MyListItem("item1");
    MyListItem item2 = new MyListItem("item2");
    MyListItem item3 = new MyListItem("item3");

    list.add(item1);
    list.add(item2);
    list.add(item3);

    MyArrayAdapter adapter = new MyArrayAdapter(this, list);
    listView.setAdapter(adapter);
}