英文:
Cannot find a setter for ~ItemBinding~ that accepts parameter type 'androidx.lifecycle.LiveData<
问题
不能找到适用于 <the_derek.dogstuff.databinding.DogItemBinding app:product> 的设置器，该设置器接受参数类型 'androidx.lifecycle.LiveData<the_derek.dogstuff.db.entity.DogEntity>'。如果绑定适配器提供了设置器，请检查适配器的注释是否正确，并且参数类型是否匹配。我已经逐行检查了我的应用程序超过两天了。我使用了 Google 提供的“BasicSample” Android Room 应用程序来模拟我的应用程序，但是当我将它包含在我的 dog_fragment.xml 中时，出现了这个错误：<includelayout="@layout/dog_item"app:product="@{dogViewModel.dog}" />“dog_item” 布局（dog_item.xml）用于显示狗的列表，当您点击它时，它会带您进入狗的详细信息屏幕（dog_fragment.xml）。没有它，一切都很正常，但是缺少“狗”图块以进入详细信息屏幕，只会显示一列咀嚼玩具。dog_fragment.xml<?xml version="1.0" encoding="utf-8"?><layout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"><data><import type="android.view.View" /><variablename="isLoading"type="boolean" /><variablename="dog"type="the_derek.dogstuff.viewmodel.DogViewModel" /></data><LinearLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"android:background="@color/cardview_light_background"android:orientation="vertical"><includelayout="@layout/dog_item"app:product="@{dogViewModel.dog}" /><FrameLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/tv_loading_chew_toys"android:layout_width="match_parent"android:layout_height="match_parent"android:text="@string/loading_chew_toys"app:visibleGone="@{isLoading}" /><FrameLayoutandroid:id="@+id/chew_toys_list_wrapper"android:layout_width="match_parent"android:layout_height="match_parent"><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/chew_toy_list"android:layout_width="match_parent"android:layout_height="match_parent"android:contentDescription="@string/cd_chew_toys_list"app:layoutManager="LinearLayoutManager"app:visibleGone="@{!isLoading}" /></FrameLayout></FrameLayout></LinearLayout></layout>DogFragment.javapublic class DogFragment extends Fragment {private static final String TAG = "\t\tDogFragment";private static final String KEY_DOG_ID = "dog_id";private final ChewToyClickCallback mChewToyClickCallback =chewToy -> {// no-op};private DogFragmentBinding mBinding;private ChewToyAdapter mChewToyAdapter;public static DogFragment forDog(int dogId) {DogFragment fragment = new DogFragment();Bundle args = new Bundle();args.putInt(KEY_DOG_ID, dogId);fragment.setArguments(args);return fragment;}@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater,@Nullable ViewGroup container,@Nullable Bundle savedInstanceState) {mBinding = DataBindingUtil.inflate(inflater, R.layout.dog_fragment, container, false);mChewToyAdapter = new ChewToyAdapter(mChewToyClickCallback);mBinding.chewToyList.setAdapter(mChewToyAdapter);return mBinding.getRoot();}@Overridepublic void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {DogViewModel.Factory factory =new DogViewModel.Factory(requireActivity().getApplication(), requireArguments().getInt(KEY_DOG_ID));final DogViewModel model =new ViewModelProvider(this, factory).get(DogViewModel.class);mBinding.setLifecycleOwner(getViewLifecycleOwner());mBinding.setDogViewModel(model);subscribeToModel(model);}private void subscribeToModel(final DogViewModel model) {model.getChewToys().observe(getViewLifecycleOwner(),chewToyEntities -> {if (chewToyEntities != null) {mBinding.setIsLoading(false);mChewToyAdapter.submitList(chewToyEntities);} else {mBinding.setIsLoading(true);}});}@Overridepublic void onDestroyView() {mBinding = null;mChewToyAdapter = null;super.onDestroyView();}}DogViewModel.javapublic class DogViewModel extends AndroidViewModel {private static final String TAG = "\t\tDogViewModel";private final LiveData<DogEntity> mObservableDog;private final LiveData<List<ChewToyEntity>> mObservableChewToys;public DogViewModel(@NonNull Application application, DataRepository repository, final int dogId) {super(application);mObservableChewToys = repository.loadChewToysById(dogId);mObservableDog = repository.loadDog(dogId);}public LiveData<List<ChewToyEntity>> getChewToys() {return mObservableChewToys;}public LiveData<DogEntity> getDog() {return mObservableDog;}public static class Factory extends ViewModelProvider.NewInstanceFactory {@NonNull private final Application mApplication;private final int mDogId;private final DataRepository mRepository;public Factory(@NonNull Application application, int dogId) {mApplication = application;mDogId = dogId;mRepository = ((DogApp) application).getRepository();}@SuppressWarnings("unchecked")@Override@NonNullpublic <T extends ViewModel> T create(@NonNull Class<T> modelClass) {return (T) new DogViewModel(mApplication, mRepository, mDogId);}}}BindingAdapters.javapublic class BindingAdapters {@BindingAdapter("visibleGone")public static void showHide(View view, boolean show) {view.setVisibility(show ? View.VISIBLE : View.GONE);}}DogClickCallback.javapublic interface DogClickCallback {void onClick(Dog dog);}dao 查询@Query("select * from dog_table where id = :dogId")LiveData<DogEntity> loadDog(int dogId);DogAdapter.javapublic class DogAdapter extends RecyclerView.Adapter<DogAdapter.DogViewHolder> {private static final String TAG = "\t\tDogAdapter";@Nullable private final DogClickCallback mDogClickCallback;List<? extends Dog><details><summary>英文:</summary>> Cannot find a setter for> <the_derek.dogstuff.databinding.DogItemBinding app:product> that> accepts parameter type> 'androidx.lifecycle.LiveData<the_derek.dogstuff.db.entity.DogEntity>'> If a binding adapter provides the setter, check that the adapter is> annotated correctly and that the parameter type matches.I’ve been going line-by-line through my app for over two days now. I used the Google provided “BasicSample” Android Room app to mock up my own app but am getting this error when I include this in my dog_fragment.xml<includelayout="@layout/dog_item"app:product="@{dogViewModel.dog}" />The “dog_item” layout (dog_item.xml) is for showing a list of dogs, when you then click on it, it will bring you to a dog details screen (dog_fragment.xml). Without it, everything works great but it’s missing the “dog” tile to play into the details screen, and will only show a list of chew_toys.> dog_fragment.xml<?xml version="1.0" encoding="utf-8"?><layout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"><data><import type="android.view.View" /><variablename="isLoading"type="boolean" /><variablename="dog"type="the_derek.dogstuff.viewmodel.DogViewModel" /></data><LinearLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"android:background="@color/cardview_light_background"android:orientation="vertical"><includelayout="@layout/dog_item"app:product="@{dogViewModel.dog}" /><FrameLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/tv_loading_chew_toys"android:layout_width="match_parent"android:layout_height="match_parent"android:text="@string/loading_chew_toys"app:visibleGone="@{isLoading}" /><FrameLayoutandroid:id="@+id/chew_toys_list_wrapper"android:layout_width="match_parent"android:layout_height="match_parent"><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/chew_toy_list"android:layout_width="match_parent"android:layout_height="match_parent"android:contentDescription="@string/cd_chew_toys_list"app:layoutManager="LinearLayoutManager"app:visibleGone="@{!isLoading}" /></FrameLayout></FrameLayout></LinearLayout></layout>> DogFragment.javapublic class DogFragment extends Fragment {private static final String TAG = "\t\tDogFragment";private static final String KEY_DOG_ID = "dog_id";private final ChewToyClickCallback mChewToyClickCallback =chewToy -> {// no-op};private DogFragmentBinding mBinding;private ChewToyAdapter mChewToyAdapter;public static DogFragment forDog(int dogId) {DogFragment fragment = new DogFragment();Bundle args = new Bundle();args.putInt(KEY_DOG_ID, dogId);fragment.setArguments(args);return fragment;}@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater,@Nullable ViewGroup container,@Nullable Bundle savedInstanceState) {mBinding = DataBindingUtil.inflate(inflater, R.layout.dog_fragment, container, false);mChewToyAdapter = new ChewToyAdapter(mChewToyClickCallback);mBinding.chewToyList.setAdapter(mChewToyAdapter);return mBinding.getRoot();}@Overridepublic void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {DogViewModel.Factory factory =new DogViewModel.Factory(requireActivity().getApplication(), requireArguments().getInt(KEY_DOG_ID));final DogViewModel model =new ViewModelProvider(this, factory).get(DogViewModel.class);mBinding.setLifecycleOwner(getViewLifecycleOwner());mBinding.setDogViewModel(model);subscribeToModel(model);}private void subscribeToModel(final DogViewModel model) {model.getChewToys().observe(getViewLifecycleOwner(),chewToyEntities -> {if (chewToyEntities != null) {mBinding.setIsLoading(false);mChewToyAdapter.submitList(chewToyEntities);} else {mBinding.setIsLoading(true);}});}@Overridepublic void onDestroyView() {mBinding = null;mChewToyAdapter = null;super.onDestroyView();}}> DogViewModel.javapublic class DogViewModel extends AndroidViewModel {private static final String TAG = "\t\tDogViewModel";private final LiveData<DogEntity> mObservableDog;private final LiveData<List<ChewToyEntity>> mObservableChewToys;public DogViewModel(@NonNull Application application, DataRepository repository, final int dogId) {super(application);mObservableChewToys = repository.loadChewToysById(dogId);mObservableDog = repository.loadDog(dogId);}public LiveData<List<ChewToyEntity>> getChewToys() {return mObservableChewToys;}public LiveData<DogEntity> getDog() {return mObservableDog;}public static class Factory extends ViewModelProvider.NewInstanceFactory {@NonNull private final Application mApplication;private final int mDogId;private final DataRepository mRepository;public Factory(@NonNull Application application, int dogId) {mApplication = application;mDogId = dogId;mRepository = ((DogApp) application).getRepository();}@SuppressWarnings("unchecked")@Override@NonNullpublic <T extends ViewModel> T create(@NonNull Class<T> modelClass) {return (T) new DogViewModel(mApplication, mRepository, mDogId);}}}> BindingAdapters.javapublic class BindingAdapters {@BindingAdapter("visibleGone")public static void showHide(View view, boolean show) {view.setVisibility(show ? View.VISIBLE : View.GONE);}}> DogClickCallback.javapublic interface DogClickCallback {void onClick(Dog dog);}> dao query@Query("select * from dog_table where id = :dogId")LiveData<DogEntity> loadDog(int dogId);> DogAdapter.javapublic class DogAdapter extends RecyclerView.Adapter<DogAdapter.DogViewHolder> {private static final String TAG = "\t\tDogAdapter";@Nullable private final DogClickCallback mDogClickCallback;List<? extends Dog> mDogList;public DogAdapter(@Nullable DogClickCallback clickCallback) {Log.i(TAG, "DogAdapter: public constructor");mDogClickCallback = clickCallback;setHasStableIds(true);}public void setDogList(final List<? extends Dog> dogList) {if (mDogList == null) {mDogList = dogList;notifyItemRangeInserted(0, dogList.size());} else {DiffUtil.DiffResult result =DiffUtil.calculateDiff(new DiffUtil.Callback() {@Overridepublic int getOldListSize() {return mDogList.size();}@Overridepublic int getNewListSize() {return dogList.size();}@Overridepublic boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {return mDogList.get(oldItemPosition).getId()== dogList.get(newItemPosition).getId();}@Overridepublic boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {Dog newDog = dogList.get(newItemPosition);Dog oldDog = mDogList.get(oldItemPosition);return newDog.getId() == oldDog.getId()&& TextUtils.equals(newDog.getName(), oldDog.getName());}});mDogList = dogList;result.dispatchUpdatesTo(this);}}@Override@NonNullpublic DogViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {DogItemBinding binding =DataBindingUtil.inflate(LayoutInflater.from(parent.getContext()), R.layout.dog_item, parent, false);binding.setCallback(mDogClickCallback);return new DogViewHolder(binding);}@Overridepublic void onBindViewHolder(@NonNull DogViewHolder holder, int position) {holder.binding.setDog(mDogList.get(position));holder.binding.executePendingBindings();}@Overridepublic int getItemCount() {return mDogList == null ? 0 : mDogList.size();}@Overridepublic long getItemId(int position) {return mDogList.get(position).getId();}static class DogViewHolder extends RecyclerView.ViewHolder {final DogItemBinding binding;public DogViewHolder(DogItemBinding binding) {super(binding.getRoot());this.binding = binding;}}}--------------------(DogEntity also has Dog model class, if that helps)I've tried Invalidate Caches/Restart, I've tried Clean Project, Rebuild Project. I've started a new project and copied my files into it.Ooh, also, this is an error in addition:import the_derek.dogstuff.databinding.DogFragmentBindingImpl;It tells me it cannot resolve **DogFragmentBindingImpl**I don't know how it's not getting generated but I assume the problems are intertwined. I don't know if I missed putting any code that could help, please let me know.(modeled after)[android architecture-components-samples][1][1]: https://github.com/android/architecture-components-samples/tree/master/BasicSample</details># 答案1**得分**: 1这是[绑定适配器][1]错误。如果您在XML中编写了'app:product'，则在您的Kotlin或Java类之一中必须有一个名为'product'的绑定适配器。例如，对于您的> app:product="@{dogViewModel.dog}"需要有类似于以下内容的代码：
@BindingAdapter("product")
fun yourFunctionName(yourViewType: YourViewType, data: List
// 在此处放置您的绑定代码
}
了解有关数据绑定和绑定适配器的更多信息。[1]: https://developer.android.com/topic/libraries/data-binding/binding-adapters<details><summary>英文:</summary>This is [binding adapter][1] error. If you write 'app:product' in your XML, there has to be binding adapter inside one of your kotlin or java classes with the name of 'product'. For example, for your> app:product="@{dogViewModel.dog}"there needs to be something like this:
@BindingAdapter("product")
fun yourFunctionName(yourViewType: YourViewType, data: List<DogEntity>?) {
// your binding code here
}
Read more about data binding and binding adapters.[1]: https://developer.android.com/topic/libraries/data-binding/binding-adapters</details># 答案2**得分**: 1[德里克·福西特的解决方案](https://stackoverflow.com/a/63601993) 告诉你，在 include 标签内部，参数名必须与所包含布局内使用的变量名匹配。```xml<includelayout="@layout/dog_item"app:dog="@{dogViewModel.dog}" />
dog_item
<data><variablename="dog"type="$path.DogClass" /></data>
在绑定方面，没有通用的参数名称与变量匹配，您可以自己定义名称，然后相应地进行设置。
英文:
the derek Fawcett's solution is telling you that the parameter name inside the include-tag has to match the variable name used inside the included layout.
<includelayout="@layout/dog_item"app:dog="@{dogViewModel.dog}" />
dog_item
<data><variablename="dog"type="$path.DogClass" /></data>
There are no general parameter names to match variables when it comes to bindings, you can define the names yourself and then set them accordingly.
答案3
得分: -3
我花了几个星期或一个月的时间，认为“app:product”是一种用于XML的标准短语或约定。我以为“product”是一个类似于“gravity”或“layout”的通用术语...如果你明白我的意思的话。因为当我发表这个问题时，我对Android还不熟悉，我从来没有想过“app:”后面的术语需要根据数据中的变量进行更改。
英文:
I spent weeks or a month thinking that "app:product" was some sort of standard phrase or convention for XML. I thought "product" was a generic term used like "gravity" or "layout"..... if you get what I'm saying. Because when I posted the question I was new to Android, I never thought that the term after "app:" needed to be changed depending on the variable in data.
<includelayout="@layout/dog_item"app:dog="@{dogViewModel.dog}" />
答案4
得分: -4
你在这里传递了一个 LiveData 对象：
app:product="@{dogViewModel.dog}"
你需要传递：
app:product="@{dogViewModel.dog.value}"
英文:
You're passing in a LiveData object here:
app:product="@{dogViewModel.dog}"
You need to pass in:
app:product="@{dogViewModel.dog.value}"
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