无限更新回收器视图列表

Question

在dagger和rxJava的帮助下，我在RecyclerView中更新了列表。一切正常，显示列表。但问题是，在日志中，我看到此列表每秒如何更新。可能是什么问题？在一个类似的项目中，但在 Java 中一切正常，列表在启动时更新一次。 我的网络模块：

@Module(includes = [ViewModelModule::class])
class NetworkModule {
companion object {
const val KEY = "key"
const val BASE_URL = "base_url"
}
@Provides
@Singleton
fun provideOkHttp(): OkHttpClient {
val httpClient = OkHttpClient.Builder()
httpClient.addInterceptor(object : Interceptor {
@Throws(IOException::class)
override fun intercept(chain: Interceptor.Chain): okhttp3.Response {
val original = chain.request()
val originalHttpUrl = original.url
val url = originalHttpUrl.newBuilder()
//.addQueryParameter("apikey", KEY)
.build()
val requestBuilder = original.newBuilder()
.url(url)
.header("apikey", KEY)
val request = requestBuilder.build()
return chain.proceed(request)
}
})
// logging interceptor
val logging = HttpLoggingInterceptor()
logging.level = HttpLoggingInterceptor.Level.BODY
httpClient.addInterceptor(logging)
return httpClient.build()
}
@Provides
@Singleton
fun provideRetrofit(): Retrofit {
return Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(provideOkHttp())
.build()
}
@Provides
@Singleton
fun provideContactsService(retrofit: Retrofit) : ContactsService{
return retrofit.create(ContactsService::class.java)
}
}

我的视图模型：

class ContactsViewModel @Inject constructor(private val contactsRepository: ContactsRepository) :
ViewModel() {
var mutableLiveData = MutableLiveData<List<ContactsModel>>()
private val disposable = CompositeDisposable()
fun getContactMutableLiveData(): MutableLiveData<List<ContactsModel>> {
loadData()
return mutableLiveData
}
fun loadData() {
disposable.add(contactsRepository.modelSingle()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith(object : DisposableSingleObserver<List<ContactsModel>>() {
override fun onSuccess(t: List<ContactsModel>) {
getContactMutableLiveData().value = t
}
override fun onError(e: Throwable) {
}
})
)
}
}

和我的活动：

contactsViewModel.getContactMutableLiveData().observe(this@ContactListActivity, Observer {
mAdapter = ContactsAdapter(this@ContactListActivity, it as ArrayList<ContactsModel>)
recycler_contacts.layoutManager =
LinearLayoutManager(applicationContext, OrientationHelper.VERTICAL, false)
recycler_contacts.adapter = mAdapter
recycler_contacts.setHasFixedSize(true)
mAdapter.sortByName()
})

Answer 1

好吧，如果您只想更新一次数据列表...我建议您查看单个实时事件，该事件将触发回收器视图的重新加载 因此

//in repo
private SingleLiveEvent<Boolean> listHasBeenUpdate=new SingleLiveEvent<>();
//setItsGetterInTheRepo
public SingleLiveEvent<Boolean> getListHasBeenUpdated(){
return listHasBeenUpdated();
}
//uponSucessfuly fetching your list from retrofit
listHasBeenUpdated=true;
//pass list to viewmodel

然后在 ViewModel 中，我将列表设置为可观察数据，一旦从改造中获取它就会更新(考虑使用房间 db 来存储它(

//use a setter to set the list from Repo
ObservableField<List<Contacts>> list=new ObservableField<>();
public SingleLiveEvent<List<Contacts>> fetchContacts(){
return myRepo.getListHasBeenUpdated();
}

现在在您的活动类中观察单个实时事件，如下所示

viewModel.fetchContacts().observe(this,contacts->{
if(contacts){
//update Recycler
}
});

希望这对你有帮助。

Answer 2

这是一个逻辑错误。您需要重写 loadData 函数，如下所示

class ContactsViewModel @Inject constructor(private val contactsRepository: ContactsRepository) :
ViewModel() {
var mutableLiveData = MutableLiveData<List<ContactsModel>>()
private val disposable = CompositeDisposable()
fun getContactMutableLiveData(): MutableLiveData<List<ContactsModel>> {
disposable.add(contactsRepository.modelSingle()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith(object : DisposableSingleObserver<List<ContactsModel>>() {
override fun onSuccess(t: List<ContactsModel>) {
mutableLiveData.value = t
}
override fun onError(e: Throwable) {
}
}))
return mutableLiveData
}
}