我正在追踪this tutorial，但遇到以下强制转换错误：java.lang.ClassCastException: com.banshai.appetit.controllers.home.OpenRestaurantsViewHolder cannot be cast to com.banshai.appetit.controllers.home.FirstOpenRestaurantVHolder at com.banshai.appetit.controllers.home.RestaurantAdapter.onBindViewHolder
尝试强制转换时，在onBindViewHolder上调用该错误：FirstOpenRestaurantVHolder firstVH = (FirstOpenRestaurantVHolder) viewholder;。我想念什么？
这是我完整的适配器：
public class RestaurantAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<Restaurant> restaurants;
private Context context;
private SharedData sharedData;
private final int FIRST_OPEN_RESTAURANT = 0;
private final int OPEN_RESTAURANT = 1;
public RestaurantAdapter(List<Restaurant> restaurantsList) {
restaurants = restaurantsList;
sharedData = SharedData.getInstance();
}
@Override
public int getItemCount() {
return restaurants.size();
}
@Override
public int getItemViewType(int position) {
//If position is 0 this means we need to use FirstOpenRestaurantVHolder
if (position == 0) {
return FIRST_OPEN_RESTAURANT;
} else if (position > 0) {
return OPEN_RESTAURANT;
}
return OPEN_RESTAURANT; //TODO ojo con este default
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
RecyclerView.ViewHolder viewHolder;
LayoutInflater inflater = LayoutInflater.from(viewGroup.getContext());
switch (viewType) {
case FIRST_OPEN_RESTAURANT:
View firstOpenRest = inflater.inflate(R.layout.intro_home_restaurant_first_card, viewGroup, false);
viewHolder = new OpenRestaurantsViewHolder(firstOpenRest);
break;
case OPEN_RESTAURANT: //TODO ojo este no va ser el default
View openRest = inflater.inflate(R.layout.intro_home_resturant_card_row, viewGroup, false);
viewHolder = new FirstOpenRestaurantVHolder(openRest);
break;
default:
View openRestaurant = inflater.inflate(R.layout.intro_home_resturant_card_row, viewGroup, false);
viewHolder = new FirstOpenRestaurantVHolder(openRestaurant);
break;
}
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder viewholder, int position) {
switch (viewholder.getItemViewType()) {
case FIRST_OPEN_RESTAURANT:
FirstOpenRestaurantVHolder firstVH = (FirstOpenRestaurantVHolder) viewholder;
firstVH.franchiseName.setText("FIRST!!!");
break;
default:
OpenRestaurantsViewHolder openVH = (OpenRestaurantsViewHolder) viewholder;
openVH.franchiseName.setText("OPEN BUT NOT FIRST");
break;
}
}
public class OpenRestaurantsViewHolder extends RecyclerView.ViewHolder {
protected TextView franchiseName;
protected TextView homeCategory;
protected ImageView restaurantPhoto;
protected ImageView franchiseLogo;
public OpenRestaurantsViewHolder(View view) {
super(view);
franchiseName = (TextView) view.findViewById(R.id.home_franchise_name);
restaurantPhoto = (ImageView) view.findViewById(R.id.home_resturant_pic);
franchiseLogo = (ImageView) view.findViewById(R.id.home_franchise_logo);
homeCategory = (TextView) view.findViewById(R.id.home_category);
}
}
public class FirstOpenRestaurantVHolder extends RecyclerView.ViewHolder {
protected TextView franchiseName;
protected TextView homeCategory;
protected ImageView restaurantPhoto;
protected ImageView franchiseLogo;
public FirstOpenRestaurantVHolder(View view) {
super(view);
franchiseName = (TextView) view.findViewById(R.id.home_first_franchise_name);
restaurantPhoto = (ImageView) view.findViewById(R.id.home_first_resturant_pic);
franchiseLogo = (ImageView) view.findViewById(R.id.home_first_franchise_logo);
homeCategory = (TextView) view.findViewById(R.id.home_first_category);
}
}
}
最佳答案
不得不更改if的代码，而不是进行切换以使其更清晰（这只是个人喜好），添加了一些控制台日志以查看发生了什么，但这应该可以工作：
public class RestaurantAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<Restaurant> restaurants;
private Context context;
private SharedData sharedData;
private final int FIRST_OPEN_RESTAURANT = 0;
private final int OPEN_RESTAURANT = 1;
public RestaurantAdapter(List<Restaurant> restaurantsList) {
restaurants = restaurantsList;
sharedData = SharedData.getInstance();
}
@Override
public int getItemCount() {
return restaurants.size();
}
@Override
public int getItemViewType(int position) {
Log.i("getItemVi(position)", "position=" + position);
//If position is 0 this means we need to use FirstOpenRestaurantVHolder
if (position == 0) {
return 0;
} else if (position > 0) {
return 1;
}
return 1; //TODO ojo con este default
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
Log.i("onCreateVewHo(viewType)", "viewType=" + viewType);
RecyclerView.ViewHolder viewHolder;
LayoutInflater inflater = LayoutInflater.from(viewGroup.getContext());
if (viewType == 0) {
View firstOpenRest = inflater.inflate(R.layout.intro_home_restaurant_first_card, viewGroup, false);
viewHolder = new FirstOpenRestaurantVHolder(firstOpenRest);
} else {
View openRestaurant = inflater.inflate(R.layout.intro_home_resturant_card_row, viewGroup, false);
viewHolder = new OpenRestaurantsViewHolder(openRestaurant);
}
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder viewholder, int position) {
Log.i("onBindViewHolder", "viewholder.getItemViewType()=" + viewholder.getItemViewType());
if (viewholder.getItemViewType() == 0) {
FirstOpenRestaurantVHolder firstVH = (FirstOpenRestaurantVHolder) viewholder;
firstVH.franchiseName.setText("FIRST!!!");
} else {
OpenRestaurantsViewHolder openVH = (OpenRestaurantsViewHolder) viewholder;
openVH.franchiseName.setText("OPEN BUT NOT FIRST");
}
}
public class OpenRestaurantsViewHolder extends RecyclerView.ViewHolder {
protected TextView franchiseName;
protected TextView homeCategory;
protected ImageView restaurantPhoto;
protected ImageView franchiseLogo;
public OpenRestaurantsViewHolder(View view) {
super(view);
franchiseName = (TextView) view.findViewById(R.id.home_franchise_name);
restaurantPhoto = (ImageView) view.findViewById(R.id.home_resturant_pic);
franchiseLogo = (ImageView) view.findViewById(R.id.home_franchise_logo);
homeCategory = (TextView) view.findViewById(R.id.home_category);
}
}
public class FirstOpenRestaurantVHolder extends RecyclerView.ViewHolder {
protected TextView franchiseName;
protected TextView homeCategory;
protected ImageView restaurantPhoto;
protected ImageView franchiseLogo;
public FirstOpenRestaurantVHolder(View view) {
super(view);
franchiseName = (TextView) view.findViewById(R.id.home_first_franchise_name);
restaurantPhoto = (ImageView) view.findViewById(R.id.home_first_resturant_pic);
franchiseLogo = (ImageView) view.findViewById(R.id.home_first_franchise_logo);
homeCategory = (TextView) view.findViewById(R.id.home_first_category);
}
}
}
关于java - 为RecyclerView实现不同的布局，但在onBindViewHolder上获取类强制转换错误，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/33378489/