2.5.0 构建一个可复用的自定义BaseAdapter

本节引言：如题，本节给大家带来的是构建一个可复用的自定义BaseAdapter，我们每每涉及到ListViewGridView等其他的Adapter控件，都需要自己另外写一个BaseAdapter类，这样显得非常麻烦，又比如，我们想在一个界面显示两个ListView的话，我们也是需要些两个BaseAdapter...这，程序员都是喜欢偷懒的哈，这节我们就来写一个可复用的自定义BaseAdapter类~1.我们一点点开始改：首先我们把上节写的自定义BaseAdapter贴下，等下我们就要对他进行升级改造/** * Created by Jay on 2015/9/21 0021. */public class MyAdapter extends BaseAdapter { private Context mContext; private LinkedList<Data> mData; public MyAdapter() { } public MyAdapter(LinkedList<Data> mData, Context mContext) { this.mData = mData; this.mContext = mContext; } @Override public int getCount() { return mData.size(); } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return position; } @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, parent, false); holder = new ViewHolder(); holder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon); holder.txt_content = (TextView) convertView.findViewById(R.id.txt_content); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } holder.img_icon.setImageResource(mData.get(position).getImgId()); holder.txt_content.setText(mData.get(position).getContent()); return convertView; } //添加一个元素 public void add(Data data) { if (mData == null) { mData = new LinkedList<>(); } mData.add(data); notifyDataSetChanged(); } //往特定位置，添加一个元素 public void add(int position,Data data){ if (mData == null) { mData = new LinkedList<>(); } mData.add(position, data); notifyDataSetChanged(); } public void remove(Data data) { if(mData != null) { mData.remove(data); } notifyDataSetChanged(); } public void remove(int position) { if(mData != null) { mData.remove(position); } notifyDataSetChanged(); } public void clear() { if(mData != null) { mData.clear(); } notifyDataSetChanged(); } private class ViewHolder { ImageView img_icon; TextView txt_content; }}升级1：将Entity设置成泛型好的，毕竟我们传递过来的Entitiy实体类可能千奇百怪，比如有Person，Book，Wether等，所以我们将Entity设置成泛型，修改后的代码如下：public class MyAdapter<T> extends BaseAdapter { private Context mContext; private LinkedList<T> mData; public MyAdapter() { } public MyAdapter(LinkedList<T> mData, Context mContext) { this.mData = mData; this.mContext = mContext; } @Override public int getCount() { return mData.size(); } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return position; } @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, parent, false); holder = new ViewHolder(); holder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon); holder.txt_content = (TextView) convertView.findViewById(R.id.txt_content); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } holder.img_icon.setImageResource(mData.get(position).getImgId()); holder.txt_content.setText(mData.get(position).getContent()); return convertView; } //添加一个元素 public void add(T data) { if (mData == null) { mData = new LinkedList<>(); } mData.add(data); notifyDataSetChanged(); } //往特定位置，添加一个元素 public void add(int position,T data){ if (mData == null) { mData = new LinkedList<>(); } mData.add(position, data); notifyDataSetChanged(); } public void remove(T data) { if(mData != null) { mData.remove(data); } notifyDataSetChanged(); } public void remove(int position) { if(mData != null) { mData.remove(position); } notifyDataSetChanged(); } public void clear() { if(mData != null) { mData.clear(); } notifyDataSetChanged(); } private class ViewHolder { ImageView img_icon; TextView txt_content; }}好的，上面我们做的事仅仅是将Data类型换成了泛型T！升级2：ViewHolder类的升级改造：我们先来看看前面我们的Vi