打造通用Adapter（适用于ListView，GridView）

通用的ViewHolder

/**
* 通用的ViewHolder
* Created by Timor on 2015/4/25.
*/
public class ViewHolder {
/**
* 一个储存ID和控件的映射关系的容器
*/
private SparseArray<View> mViews;
private int mPosition;
private View mConvertView;

public ViewHolder(Context context, ViewGroup parent, int layoutId, int position) {
this.mViews = new SparseArray<View>();
this.mPosition = position;
this.mConvertView = LayoutInflater.from(context).inflate(layoutId, parent, false);
mConvertView.setTag(this);
}

/**
* 拿到一个ViewHolder对象
*/
public static ViewHolder getHolder(Context context, View convertView, ViewGroup parent, int layoutId, int position) {
if (convertView == null) {
return new ViewHolder(context, parent, layoutId, position);
} else {
ViewHolder holder = (ViewHolder) convertView.getTag();
holder.mPosition = position;
return holder;
}
}

/**
* 通过ID获取控件
*/
public <T extends View> T getView(int viewId) {
View view = mViews.get(viewId);
if (view == null) {
view = mConvertView.findViewById(viewId);
mViews.put(viewId, view);
}
return (T) view;
}

public View getConvertView() {
return mConvertView;
}

/**
* 设置TextView内容
*/
public ViewHolder setText(int viewId, String text) {
TextView textView = getView(viewId);
textView.setText(text);
return this;
}

/**
* 设置图片
*/
public ViewHolder setImage(int viewId, int resId) {
ImageView imageView = getView(viewId);
imageView.setImageResource(resId);
return this;
}
}

通用的Adapter

/**
* 通用Adapter。
* 使用：继承CommonAdapter，然后重写convert，在该方法里完成数据到控件的映射。holder持有控件映射，item是数据bean。
*/
public abstract class CommonAdapter<T> extends BaseAdapter {
protected Context mContext;
protected List<T> mDatas;
protected LayoutInflater mInflater;
protected int mItemLayoutId;

public CommonAdapter(Context context, int itemLayoutId, List<T> datas) {
this.mContext = context;
this.mDatas = datas;
this.mItemLayoutId = itemLayoutId;
mInflater = LayoutInflater.from(context);
}

@Override
public int getCount() {
return mDatas.size();
}

@Override
public T getItem(int position) {
return mDatas.get(position);
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = ViewHolder.getHolder(mContext, convertView, parent, mItemLayoutId, position);
convert(holder, getItem(position));
return holder.getConvertView();
}

public abstract void convert(ViewHolder holder, T item);

private ViewHolder getViewHolder(int position, View convertView, ViewGroup parent) {
return ViewHolder.getHolder(mContext, convertView, parent, mItemLayoutId,
position);
}
}

使用

mAdapter = new CommonAdapter<Conversation>(getActivity(),   R.layout.view_item_conversation_list, mDatas) {
@Override
public void convert(ViewHolder holder, Conversation item) {
holder.setText(R.id.tv_name, item.getName())
.setText(R.id.tv_msg, item.getMsg())
.setText(R.id.tv_time, item.getPostTime());
holder.setImage(R.id.iv_avatar, item.getAvatar());
}
};