1.複用ConvertView：
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    convertView = LayoutInflater.from(mContext).inflate(R.layout.item_list_animal,parent,false);
    ImageView img_icon = (ImageView) convertView.findViewById(R.id.img_icon);
    TextView txt_aName = (TextView) convertView.findViewById(R.id.txt_aName);
    TextView txt_aSpeak = (TextView) convertView.findViewById(R.id.txt_aSpeak);

    img_icon.setBackgroundResource(mData.get(position).getaIcon());
    txt_aName.setText(mData.get(position).getaName());
    txt_aSpeak.setText(mData.get(position).getaSpeak());
    return convertView;
}
inflate()每次都要載入一次xml，其實這個convertView是系統提供給我們的可供服用的View 的快取物件，那就坐下判斷咯，修改下，優化後的程式碼：

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

    if(convertView == null){
        convertView = LayoutInflater.from(mContext).inflate(R.layout.item_list_animal,parent,false);
    }

    ImageView img_icon = (ImageView) convertView.findViewById(R.id.img_icon);
    TextView txt_aName = (TextView) convertView.findViewById(R.id.txt_aName);
    TextView txt_aSpeak = (TextView) convertView.findViewById(R.id.txt_aSpeak);

    img_icon.setBackgroundResource(mData.get(position).getaIcon());
    txt_aName.setText(mData.get(position).getaName());
    txt_aSpeak.setText(mData.get(position).getaSpeak());
    return convertView;
}

2.ViewHolder重用元件
getView()會被呼叫多次，那麼findViewById不一樣得呼叫多次，而我們的ListView的Item 一般都是一樣的佈局，我們可以對這裡在優化下，我們可以自己定義一個ViewHolder類來對這一部分 進行效能優化！修改後的程式碼如下：
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder = null;
    if(convertView == null){
        convertView = LayoutInflater.from(mContext).inflate(R.layout.item_list_animal,parent,false);
        holder = new ViewHolder();
        holder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon);
        holder.txt_aName = (TextView) convertView.findViewById(R.id.txt_aName);
        holder.txt_aSpeak = (TextView) convertView.findViewById(R.id.txt_aSpeak);
        convertView.setTag(holder);   //將Holder儲存到convertView中
    }else{
        holder = (ViewHolder) convertView.getTag();
    }
    holder.img_icon.setBackgroundResource(mData.get(position).getaIcon());
    holder.txt_aName.setText(mData.get(position).getaName());
    holder.txt_aSpeak.setText(mData.get(position).getaSpeak());
    return convertView;
}

static class ViewHolder{
    ImageView img_icon;
    TextView txt_aName;
    TextView txt_aSpeak;
}