一、概述
相信Android开发，特别是电商项目开发，使用RecyclerView、ListView、GridView是正常不过的了。一个项目下来，基本就是一直在写Adapter。刚开始写Adapter觉得没什么，无非就是ListView的继承BaseAdapter复写几个方法，getView里面使用ViewHolder模式；RecyclerView的就继承 RecyclerView.Adapter，复写onCreateViewHolder、onBindViewHolder然后实现便完事。但当我写到10遍、100遍甚至更多的时候，我就不想写了，反正都是这种写法，也没什么新的套路。于是我就想写一个RecyclerView、ListView、GridView通用的Adapter。
二、常见ListView、RecyclerView Adapter写法的例子
代码没什么难度可以随便看看就好。
public class ListViewAdapter extends BaseAdapter
{
private LayoutInflater mInflater;
private Context mContext;
private List<String> mDatas;
private int mLayoutId;
public ListViewAdapter(Context context, List<String> mDatas,int layoutId)
{
mInflater = LayoutInflater.from(context);
this.mContext = context;
this.mDatas = mDatas;
this.mLayoutId = layoutId;
}
@Override
public int getCount()
{
return mDatas.size();
}
@Override
public Object 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 viewHolder = null;
if (convertView == null)
{
convertView = mInflater.inflate(R.mLayoutId, parent, false);
viewHolder = new ViewHolder();
viewHolder.mTextView = (TextView) convertView
.findViewById(R.id.id_tv);
convertView.setTag(viewHolder);
} else
{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.mTextView.setText(mDatas.get(position));
return convertView;
}
private final class ViewHolder
{
TextView mTextView;
}
}
private class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.Holder> {
private LayoutInflater mInflater;
private Context mContext;
private List<String> mData;
private int mLayoutId;
public RecyclerAdapter(Context context, List<String> data, int layoutId) {
mInflater = LayoutInflater.from(context);
this.mContext = context;
this.mData = data;
this.mLayoutId = layoutId;
}
@Override
public Holder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(mLayoutId, parent, false);
return new Holder(view);
}
@Override
public void onBindViewHolder(Holder holder, int position) {
holder.tv.setText(mData.get(position));
}
@Override
public int getItemCount() {
return mData.size();
}
class Holder extends RecyclerView.ViewHolder {
public TextView tv;
public Holder(View itemView) {
super(itemView);
tv = itemView.findViewById(R.id.tv);
}
}
}
三、ListView、RecyclerView Adapter一些共性分析
1. 要显示的条目个数
2. 要显示和条目对应的类型
3. ListView、RecyclerView中，总共有多少个条目类型
4. 根据不同的条目类型加载不同的View
5. ListView复用条目convertView，RecyclerView自带ViewHoler复用
四、抽取RecyclerView、ListView、GridView适配器的基类
由于要通用RecyclerView、ListView、GridView只能将RecyclerView.Adapter和ListAdapter，SpinnerAdapter
这些都给实现了。里面也没多少个方法，其实也是很简单。至于一些方法的实现我考贝BaseAdapter的实现，
大家可以去看看BaseAdapter的源码。
public class BaseAdapter extends RecyclerView.Adapter implements ListAdapter, SpinnerAdapter {
private final DataSetObservable mDataSetObservable = new DataSetObservable();
// RecyclerView========================================================================
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return null;
}
// RecyclerView
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
}
// RecyclerView
@Override
public int getItemCount() {
return 0;
}
// RecyclerView========================================================================
// ListView========================================================================
@Override
public boolean areAllItemsEnabled() {
return true;
}
@Override
public boolean isEnabled(int position) {
return true;
}
@Override
public void registerDataSetObserver(DataSetObserver observer) {
mDataSetObservable.registerObserver(observer);
}
@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
mDataSetObservable.unregisterObserver(observer);
}
public void notifyListDataSetChanged() {
mDataSetObservable.notifyChanged();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return null;
}
@Override
public int getViewTypeCount() {
return 1;
}
@Override
public int getItemViewType(int position) {
return 0;
}
@Override
public int getCount() {
return 0;
}
@Override
public boolean isEmpty() {
return getCount() == 0;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
return getView(position, convertView, parent);
}
}
五、抽取支持ListView、 GridView、 RecyclerView多条目的共性
public interface QuickMultiSupport<T> {
/**
* 获取多条目View类型的数量
*/
int getViewTypeCount();
/**
* 根据数据，获取多条目布局ID
*/
int getLayoutId(T data);
/**
* 根据数据，获取多条目的ItemViewType
*/
int getItemViewType(T data);
/**
* 是否合并条目-->>使用RecyclerView时，如果无效，请用原生的RecyclerView
*/
boolean isSpan(T data);
六、打造RecyclerView、ListView、GridView通用的适配器
由于要同时适配RecyclerView、ListView、GridView，也就等于把两个Adapter的实现放在一个类里面
所以代码有点多，但代码我已分开，很容易看。
还有数据都复制出来的，条目的增删改查都在Adapter里面。
/**
* RecyclerView、ListView、GridView通用的适配器
*/
public abstract class QuickAdapter<T> extends BaseAdapter {
private Context mContext;
private List<T> mData;
private int mLayoutId;
private QuickMultiSupport<T> mSupport;
private boolean isRecycler;
private int mPosition;
public QuickAdapter(Context context, List<T> data, int layoutId) {
this.mContext = context;
this.mData = data == null ? new ArrayList<T>() : new ArrayList<T>(data);
this.mLayoutId = layoutId;
}
public QuickAdapter(Context context, List<T> data, QuickMultiSupport<T> support) {
this(context, data, 0);
this.mSupport = support;
}
@Override
public int getCount() {
return mData.size();
}
@Override
public T getItem(int position) {
return mData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
QuickViewHolder holder;
if (convertView == null) {
int layoutId = mLayoutId;
// 多条目的
if (mSupport != null) {
layoutId = mSupport.getLayoutId(mData.get(position));
}
// 创建ViewHolder
holder = createListHolder(parent, layoutId);
} else {
holder = (QuickViewHolder) convertView.getTag();
// 防止失误，还要判断
if (mSupport != null) {
int layoutId = mSupport.getLayoutId(mData.get(position));
// 如果布局ID不一样，又重新创建
if (layoutId != holder.getLayoutId()) {
// 创建ViewHolder
holder = createListHolder(parent, layoutId);
}
}
}
// 绑定View的数据
convert(holder, mData.get(position), position);
return holder.itemView;
}
/**
* 创建ListView的Holer
*/
@NonNull
private QuickViewHolder createListHolder(ViewGroup parent, int layoutId) {
QuickViewHolder holder;
View itemView = LayoutInflater.from(mContext).inflate(layoutId, parent, false);
holder = new QuickViewHolder(itemView, layoutId);
itemView.setTag(holder);
return holder;
}
/**
* ViewType的数量
*/
@Override
public int getViewTypeCount() {
// 多条目的
if (mSupport != null) {
return mSupport.getViewTypeCount() + super.getViewTypeCount();
}
return super.getViewTypeCount();
}
/**
* 这个方法是共用的
*/
@Override
public int getItemViewType(int position) {
mPosition = position;
// 多条目的
if (mSupport != null) {
return mSupport.getItemViewType(mData.get(position));
}
return super.getItemViewType(position);
}
// RecyclerView=================================================================================
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
isRecycler = true;
// 如果是多条目，viewType就是布局ID
View view;
if (mSupport != null) {
int layoutId = mSupport.getLayoutId(mData.get(mPosition));
view = LayoutInflater.from(mContext).inflate(layoutId, parent, false);
} else {
view = LayoutInflater.from(mContext).inflate(mLayoutId, parent, false);
}
QuickViewHolder holder = new QuickViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof QuickViewHolder) {
convert((QuickViewHolder) holder, mData.get(position), position);
}
}
@Override
public int getItemCount() {
return mData.size();
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
if (mSupport == null || recyclerView == null) {
return;
}
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
final GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
final GridLayoutManager.SpanSizeLookup spanSizeLookup = gridLayoutManager.getSpanSizeLookup();
// 如果设置合并单元格就占用SpanCount那个多个位置
gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
if (mSupport.isSpan(mData.get(position))) {
return gridLayoutManager.getSpanCount();
} else if (spanSizeLookup != null) {
return spanSizeLookup.getSpanSize(position);
}
return 1;
}
});
gridLayoutManager.setSpanCount(gridLayoutManager.getSpanCount());
}
}
@Override
public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {
if (mSupport == null) {
return;
}
int position = holder.getLayoutPosition();
// 如果设置合并单元格
if (mSupport.isSpan(mData.get(position))) {
ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
if (lp != null && lp instanceof StaggeredGridLayoutManager.LayoutParams) {
StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
p.setFullSpan(true);
}
}
}
// RecyclerView=================================================================================
/**
* 绑定View的数据
*/
protected abstract void convert(QuickViewHolder holder, T item, int position);
//==========================================数据相关================================================
public void add(T elem) {
mData.add(elem);
notifyData();
}
public void addAll(List<T> data) {
mData.addAll(data);
notifyData();
}
public void addFirst(T elem) {
mData.add(0, elem);
notifyData();
}
public void set(T oldElem, T newElem) {
set(mData.indexOf(oldElem), newElem);
notifyData();
}
public void set(int index, T elem) {
mData.set(index, elem);
notify();
}
public void remove(T elem) {
mData.remove(elem);
notifyData();
}
public void remove(int index) {
mData.remove(index);
notifyData();
}
public void replaceAll(List<T> elem) {
mData.clear();
mData.addAll(elem);
notifyData();
}
/**
* 清除
*/
public void clear() {
mData.clear();
notifyData();
}
private void notifyData() {
if (isRecycler) {
notifyDataSetChanged();
} else {
notifyListDataSetChanged();
}
}
public List<T> getData() {
return mData;
}
}
七、通用ViewHolder的抽取
ViewHolder最主要就是实现平时常用的方法，比如：点击事件、长按事件、给TextView设置内容等等
如果不够，实际开发可以自己添加。
public class QuickViewHolder extends RecyclerView.ViewHolder {
private SparseArray<WeakReference<View>> mViews;
private int mLayoutId;
public QuickViewHolder(View itemView) {
this(itemView, -1);
}
public QuickViewHolder(View itemView, int layoutId) {
super(itemView);
mViews = new SparseArray<>();
this.mLayoutId = layoutId;
}
public int getLayoutId() {
return mLayoutId;
}
/**
* 设置条目的点击事件
*/
public QuickViewHolder setOnClickListener(View.OnClickListener listener) {
itemView.setOnClickListener(listener);
return this;
}
/**
* 设置条目的长按事件
*/
public QuickViewHolder setOnLongClickListener(View.OnLongClickListener listener) {
itemView.setOnLongClickListener(listener);
return this;
}
/**
* 设置View的点击事件
*
* @return
*/
public QuickViewHolder setOnClickListener(int viewId, View.OnClickListener listener) {
View view = getView(viewId);
if (view != null) {
view.setOnClickListener(listener);
}
return this;
}
/**
* 获取条目的View
*/
public View getView() {
return itemView;
}
/**
* 根据ID获取条目里面的View
*/
public <T extends View> T getView(int viewId) {
WeakReference<View> viewWeakReference = mViews.get(viewId);
View view = null;
if (viewWeakReference == null) {
view = itemView.findViewById(viewId);
if (view != null) {
mViews.put(viewId, new WeakReference<>(view));
}
} else {
view = viewWeakReference.get();
}
return (T) view;
}
public QuickViewHolder setText(int viewId, CharSequence text) {
TextView tv = getView(viewId);
if (tv != null && !TextUtils.isEmpty(text)) {
tv.setText(text);
}
return this;
}
/**
* 设置图片背景颜色
*/
public QuickViewHolder setTextColor(int viewId, int color) {
TextView view = getView(viewId);
if (view != null) {
view.setTextColor(color);
}
return this;
}
/**
* 设置控件是否可见
*/
public QuickViewHolder setVisible(int viewId, int visible) {
View view = getView(viewId);
view.setVisibility(visible);
return this;
}
/**
* 设置控件选中
*/
public QuickViewHolder setChecked(int viewId, boolean checked) {
Checkable view = getView(viewId);
view.setChecked(checked);
return this;
}
/**
* 设置控件背景
*/
public QuickViewHolder setBackgroundRes(int viewId, int backgroundRes) {
View view = getView(viewId);
view.setBackgroundResource(backgroundRes);
return this;
}
/**
* 设置图片
*/
public QuickViewHolder setImageResource(int viewId, int imageResId) {
ImageView imageView = getView(viewId);
imageView.setImageResource(imageResId);
return this;
}
/**
* 设置图片
*/
public QuickViewHolder setImageBitmap(int viewId, Bitmap bitmap) {
ImageView imageView = getView(viewId);
imageView.setImageBitmap(bitmap);
return this;
}
}
八、项目实际使用
我只写了多条目的测试使用，对于一种类型的写法更为简单，我就不写了。
public class MainActivity extends AppCompatActivity {
private List<IViewType> mData = new ArrayList<>();
private QuickMultiSupport<IViewType> mQuickSupport;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initData();
initViews();
}
/**
* 多条目的ViewType
*/
public interface IViewType {
int getItemViewType();
}
private void initData() {
for (int i = 0; i < 199; i++) {
if (i % 10 == 0) {
MultiBean bean = new MultiBean();
bean.name = "mData--------" + i;
mData.add(bean);
} else {
MultiBean1 bean = new MultiBean1();
bean.name = "mData--------" + i;
mData.add(bean);
}
}
// 多条目支持
mQuickSupport = new QuickMultiSupport<IViewType>() {
// 条目总共两种类型
@Override
public int getViewTypeCount() {
return 2;
}
// 根据不用的JavaBean返回不同的布局
@Override
public int getLayoutId(IViewType data) {
if (data instanceof MultiBean) {
return R.layout.item_list1;
}
return R.layout.item_list;
}
@Override
public int getItemViewType(IViewType data) {
return data.getItemViewType();
}
@Override
public boolean isSpan(IViewType data) {
// 是否占用一个条目，针对RecyclerView
if (data instanceof MultiBean) {
return true;
}
return false;
}
};
}
private void initViews() {
ListView listView = findViewById(R.id.list_view);
RecyclerView recyclerView = findViewById(R.id.recycler_view);
// ListView设置Adapter
listView.setAdapter(new CommAdapter(this, mData, mQuickSupport));
// RecyclerView设置Adapter
recyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
recyclerView.setAdapter(new CommAdapter(this, mData, mQuickSupport));
}
class CommAdapter extends QuickAdapter<IViewType> {
public CommAdapter(Context context, List<IViewType> data, int layoutId) {
super(context, data, layoutId);
}
public CommAdapter(Context context, List<IViewType> data, QuickMultiSupport<IViewType> support) {
super(context, data, support);
}
@Override
protected void convert(QuickViewHolder holder, IViewType item, final int position) {
holder.setText(R.id.tv, item.toString());
holder.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 点击移除当前条目
remove(position);
}
});
}
}
}
至此无论是RecyclerView还是ListView终于只用一个Adapter，是不是很开心
项目运行的实际效果：左边是ListView，右边是RecyclerView。
实际效果.jpg
九、感谢
鸿洋大神的
1.Android 快速开发系列 打造万能的ListView GridView 适配器
2.为RecyclerView打造通用Adapter 让RecyclerView更加好用
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