ListView之BaseAdapter

建议：

public class MyAdapter extends BaseAdapter{
    private List<ItemBean> mList;//数据源
    private LayoutInflater mInflater;//布局装载器对象

    // 通过构造方法将数据源与数据适配器关联起来
    // context:要使用当前的Adapter的界面对象
    public MyAdapter(Context context, List<ItemBean> list) {
        mList = list;
        mInflater = LayoutInflater.from(context);
    }

    @Override
    //ListView需要显示的数据数量
    public int getCount() {
        return mList.size();
    }

    @Override
    //指定的索引对应的数据项
    public Object getItem(int position) {
        return mList.get(position);
    }

    @Override
    //指定的索引对应的数据项ID
    public long getItemId(int position) {
        return position;
    }

    @Override
    //返回每一项的显示内容
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        //如果view未被实例化过，缓存池中没有对应的缓存
        if (convertView == null) {
            viewHolder = new ViewHolder();
            // 由于我们只需要将XML转化为View，并不涉及到具体的布局，所以第二个参数通常设置为null
            convertView = mInflater.inflate(R.layout.item, null);

            //对viewHolder的属性进行赋值
            viewHolder.imageView = (ImageView) convertView.findViewById(R.id.iv_image);
            viewHolder.title = (TextView) convertView.findViewById(R.id.tv_title);
            viewHolder.content = (TextView) convertView.findViewById(R.id.tv_content);

            //通过setTag将convertView与viewHolder关联
            convertView.setTag(viewHolder);
        }else{//如果缓存池中有对应的view缓存，则直接通过getTag取出viewHolder
            viewHolder = (ViewHolder) convertView.getTag();
        }
        // 取出bean对象
        ItemBean bean = mList.get(position);

        // 设置控件的数据
        viewHolder.imageView.setImageResource(bean.itemImageResId);
        viewHolder.title.setText(bean.itemTitle);
        viewHolder.content.setText(bean.itemContent);

        return convertView;
    }
    // ViewHolder用于缓存控件，三个属性分别对应item布局文件的三个控件
    class ViewHolder{
        public ImageView imageView;
        public TextView title;
        public TextView content;
    }

MyAdapter1 myAdapter=new MyAdapter1(getContext(),list);
        listView.setAdapter(myAdapter);
        //设置listview点击事件
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Toast.makeText(getActivity(),""+i,Toast.LENGTH_LONG).show();
            }
        });
        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener(){
            @Override
            public boolean onItemLongClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                // TODO Auto-generated method stub
                // When clicked, show a toast with the TextView text
                Toast.makeText(getActivity(), "2131"+arg2+"--"+arg3, Toast.LENGTH_SHORT).show();
                return false;
            }
        });

不建议：

import android.content.Context;
import android.database.DataSetObserver;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.SpinnerAdapter;
import android.widget.TextView;

import com.exam_assistant.R;

public class MyAdapter extends BaseAdapter {
    private Context mContext;
    private String data[];

    public MyAdapter(Context mContext, String[] data) {
        this.mContext = mContext;
        this.data = data;
    }

    public MyAdapter(Context mContext) {
        this.mContext = mContext;
    }

    @Override
    public int getCount() {
        return data.length;
    }

    @Override
    public Object getItem(int position) {
        return data[position];
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view;
        if (convertView == null) {
            view = LayoutInflater.from(mContext).inflate(R.layout.layout_ltem_practice, parent, false);
            TextView textView = view.findViewById(R.id.ltem);
            textView.setText(data[position]);
            Log.d("456", "新建的item: " + position);
        } else {
            view = convertView;
            Log.d("123", "回收的item" + position);
        }
        return view;
    }
}