我有一个包含所有状态的通用CA。我到处都用它。但是此类非常繁琐，不符合Adapter
DRY是否可以通过保留public class AdapterWithStates extends RecyclerView.Adapter {
private static final int STATE_NORMAL = 0;
public static final int STATE_LOADING = 1;
public static final int STATE_EMPTY = 3;
public static final int STATE_ERROR = 4;
public static final int STATE_ERROR_CONNECTION = 5;
private static final int TYPE_NORMAL = 1000;
private static final int TYPE_LOADING = 1001;
private static final int TYPE_LOADING_MORE = 1002;
private static final int TYPE_EMPTY = 1003;
private static final int TYPE_ERROR = 1004;
private static final int TYPE_ERROR_CONNECTION = 1005;
private static final int TYPE_ERROR_LOADING = 1006;
private static final int TYPE_ERROR_CONNECTION_LOADING = 1007;
private int state = STATE_LOADING;
private List<Specialist> specialistsList;
private Context context;
private boolean loading = false;
private AdapterListener mListener;
public AdapterWithStates(Context context,
List<Specialist> specialistsList,
AdapterListener adapterListener) {
this.specialistsList = specialistsList;
this.context = context;
this.mListener = adapterListener;
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
switch (viewType) {
case TYPE_LOADING:
return new ViewHolders.LoadingViewHolder(LayoutInflater.from(context)
.inflate(R.layout.loading_row, parent, false));
case TYPE_LOADING_MORE:
return new ViewHolders.LoadMoreProgressViewHolder(LayoutInflater.from(context)
.inflate(R.layout.load_more_row, parent, false));
case TYPE_EMPTY:
return new ViewHolders.EmptyViewHolder(LayoutInflater.from(context)
.inflate(R.layout.error_empty_row, parent, false));
case TYPE_ERROR:
if (specialistsList.size() > 0) {
return new ViewHolders.LoadMoreProgressViewHolder(LayoutInflater.from(context)
.inflate(R.layout.load_more_row, parent, false));
} else {
return new ViewHolders.ErrorViewHolder(LayoutInflater.from(context)
.inflate(R.layout.error_row, parent, false));
}
case TYPE_ERROR_CONNECTION:
if (specialistsList.size() > 0) {
return new ViewHolders.LoadMoreProgressViewHolder(LayoutInflater.from(context)
.inflate(R.layout.load_more_row, parent, false));
} else {
return new ViewHolders.ErrorConnectionViewHolder(LayoutInflater.from(context)
.inflate(R.layout.error_connection_row, parent, false));
}
case TYPE_ERROR_LOADING:
return new ViewHolders.ErrorLoadMoreViewHolder(LayoutInflater.from(context)
.inflate(R.layout.error_load_more_row, parent, false));
case TYPE_ERROR_CONNECTION_LOADING:
return new ViewHolders.ErrorLoadMoreViewHolder(LayoutInflater.from(context)
.inflate(R.layout.error_connection_load_more_row, parent, false));
default:
return new MyViewHolder(LayoutInflater.from(context)
.inflate(R.layout.specialist_short_layout_row, parent, false));
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
if (holder instanceof ViewHolders.LoadingViewHolder) {
onBindLoadingViewHolder((ViewHolders.LoadingViewHolder) holder);
} else if (holder instanceof ViewHolders.LoadMoreProgressViewHolder) {
onBindLoadMoreViewHolder((ViewHolders.LoadMoreProgressViewHolder) holder, position);
} else if (holder instanceof ViewHolders.ErrorLoadMoreViewHolder) {
onBindErrorLoadMoreViewHolder((ViewHolders.ErrorLoadMoreViewHolder) holder, position);
} else if (holder instanceof ViewHolders.EmptyViewHolder) {
onBindEmptyViewHolder((ViewHolders.EmptyViewHolder) holder, position);
} else if (holder instanceof ViewHolders.ErrorViewHolder) {
onBindErrorViewHolder((ViewHolders.ErrorViewHolder) holder, position);
} else if (holder instanceof ViewHolders.ErrorConnectionViewHolder) {
onBindErrorConnectionViewHolder((ViewHolders.ErrorConnectionViewHolder) holder, position);
} else if (holder instanceof MyViewHolder) {
onBindDefaultViewHolder((MyViewHolder) holder, position);
}
}
private void onBindDefaultViewHolder(MyViewHolder holder, int position) {
Specialist specialist = specialistsList.get(position);
holder.mName.setText(specialist.getFullName());
holder.mService.setText(specialist.getSex());
holder.mRatingBar.setRating(specialist.getRating() != null ? Float.parseFloat(specialist.getRating()) : 0);
}
private void onBindErrorViewHolder(ViewHolders.ErrorViewHolder holder, final int position) {
holder.retryBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mListener != null)
mListener.onRetryClickListener(position);
}
});
}
private void onBindErrorConnectionViewHolder(ViewHolders.ErrorConnectionViewHolder holder, final int position) {
holder.retryBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mListener != null)
mListener.onRetryClickListener(position);
}
});
}
private void onBindEmptyViewHolder(ViewHolders.EmptyViewHolder holder, final int position) {
holder.mEmptyLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mListener != null)
mListener.onEmptyClickListener(position);
}
});
}
private void onBindLoadMoreViewHolder(ViewHolders.LoadMoreProgressViewHolder holder, final int position) {
holder.errorLayout.setVisibility(View.GONE);
holder.progressBar.setVisibility(View.VISIBLE);
holder.progressBar.setIndeterminate(true);
if (!loading) {
if (mListener != null) {
mListener.onLoadMore(position);
}
loading = true;
}
}
private void onBindErrorLoadMoreViewHolder(ViewHolders.ErrorLoadMoreViewHolder holder, final int position) {
holder.retryBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mListener != null)
mListener.onRetryClickListener(position);
}
});
}
private void onBindLoadingViewHolder(ViewHolders.LoadingViewHolder holder) {
holder.progressBar.setIndeterminate(true);
}
@Override
public int getItemCount() {
switch (state) {
case STATE_LOADING:
case STATE_EMPTY:
case STATE_ERROR_CONNECTION:
case STATE_ERROR:
if (specialistsList != null && specialistsList.size() != 0)
return specialistsList.size();
else
return 1;
default:
return specialistsList.size();
}
}
@Override
public int getItemViewType(int position) {
switch (state) {
case STATE_LOADING:
if (specialistsList.size() == 0)
return TYPE_LOADING;
else if (specialistsList.get(position) == null)
return TYPE_LOADING_MORE;
else
return TYPE_NORMAL;
case STATE_EMPTY:
return TYPE_EMPTY;
case STATE_ERROR:
if (specialistsList.size() == 0)
return TYPE_ERROR;
else if (specialistsList.get(position) == null)
return TYPE_ERROR_LOADING;
else
return TYPE_NORMAL;
case STATE_ERROR_CONNECTION:
if (specialistsList.size() == 0)
return TYPE_ERROR_CONNECTION;
else if (specialistsList.get(position) == null)
return TYPE_ERROR_CONNECTION_LOADING;
else
return TYPE_NORMAL;
default:
if (specialistsList.get(position) != null) {
return TYPE_NORMAL;
} else {
return TYPE_LOADING_MORE;
}
}
}
class MyViewHolder extends RecyclerView.ViewHolder {
CardView mRoot;
TextView mName;
TextView mService;
RatingBar mRatingBar;
MyViewHolder(View view) {
super(view);
mRoot = view.findViewById(R.id.root_layout);
mName = view.findViewById(R.id.name_tv);
mService = view.findViewById(R.id.service_tv);
mRatingBar = view.findViewById(R.id.ratingBar);
mRoot.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mListener != null)
mListener.onItemClickListener(getAdapterPosition());
}
});
}
}
public int getState() {
return state;
}
public void setState(int state) {
this.state = state;
notifyDataSetChanged();
}
public void update(List<Specialist> newList) {
specialistsList = newList;
notifyItemInserted(specialistsList.size());
}
public void removeLastItem() {
if (specialistsList != null && specialistsList.size() != 0)
specialistsList.remove(specialistsList.size() - 1);
notifyDataSetChanged();
}
public void setLoaded() {
state = STATE_NORMAL;
loading = false;
}
}
方法和onBindDefaultViewHolder类进行实现来减少或继承？
答案 0 :(得分：2)
您可以使您的SpecialistAdapter抽象：
public abstract class SpecialistAdapter extends RecyclerView.Adapter {
//...
public abstract RecyclerView.ViewHolder makeViewHolder();
}
然后，当您扩展SpecialistAdapter时，您仍然需要实现onBindViewHolder()以及新的makeViewHolder()方法。
在onCreateViewHolder()下，您可以调用makeViewHolder()而不是创建新的MyViewHolder实例：
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
RecyclerView.ViewHolder vh;
if (viewType == VIEW_ITEM) {
vh = makeViewHolder();
} else {
View v = LayoutInflater.from(context).inflate(R.layout.loading_row, parent, false);
vh = new ProgressViewHolder(v);
}
return vh;
}