android - 如何使用 MVP 方法从水平回收视图 kotlin 显示 JSON 数据
问题描述
我希望你一切都好。
我已经构建了我的代码并根据 MVP 样式构建以及提取 JSON 数据,但是当我运行代码时,水平回收视图和 JSON 数据没有显示。我尝试浏览每一行代码并观看其他教程,但仍然没有结果。
下面是我的主要活动:
class ProductCategoryActivity : BaseMvpActivity<ProductCategoryActivityView, ProductCategoryActivityPresnter> (),
ProductCategoryActivityView, CategoryAdapter.onItemClickListener{
private lateinit var binding: FragmentProductCategoryBinding
val data :MutableList<CateogryResponse> = ArrayList()
val adapter= CategoryAdapter(data, this)
@Inject
lateinit var presenter: ProductCategoryActivityPresnter
@Inject
lateinit var progressDialog: ProgressDialog
override fun onCreateComponent() {
userComponent.plus(CategoryActivityModule(this)).inject(this)
}
override fun providePresenter(): ProductCategoryActivityPresnter {
return presenter
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = FragmentProductCategoryBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
presenter.fetchcatogries()
showdata(ArrayList())
}
override fun showError(message: String) {
}
override fun showProgress() {
}
override fun hideProgress() {
}
override fun showdata(data: ArrayList<CateogryResponse>) {
val layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
recyclerViewPrimary.layoutManager = layoutManager
recyclerViewPrimary.setHasFixedSize(true)
recyclerViewPrimary.adapter = adapter
for(i in data)
data.add(CateogryResponse("product"))
}
override fun onItemClick(position: Int) {
Toast.makeText(this, "Item $position clicked", Toast.LENGTH_SHORT).show()
val clickedItem = data[position]
adapter.notifyItemChanged(position)
}
}
这是我的主持人:
@ActivityScope
class ProductCategoryActivityPresnter @Inject constructor(
private val stringProvider: StringProvider,
@AndroidScheduler private val observeOnScheduler: Scheduler,
@IOScheduler private val subscribeOnScheduler: Scheduler,
private val getCategoryUseCase: CategoryUseCase
) : BasePresenter<ProductCategoryActivityView>() {
lateinit var catogriesservice: CategoryRepositoryImpl
val catogriesLoadError = MutableLiveData<Boolean>()
val loading = MutableLiveData<Boolean>()
var catogries: ArrayList<CateogryResponse> = arrayListOf()
override fun onCreatePresenter(savedInstanceState: Bundle?) {
}
override fun onSaveInstanceState(outState: Bundle?) {
}
override fun onLoadData(arguments: Bundle?) {
fetchcatogries()
}
fun fetchcatogries() {
getCategoryUseCase.execute()
.observeOn(observeOnScheduler)
.subscribeOn(subscribeOnScheduler)
.subscribe(
SingleRequestSubscriber(
{
it
if (it != null && it.size > 0) {
catogries.removeAll(catogries)
catogries.addAll(it)
}
},
onFailure = { appException ->
view?.showError(
ErrorHandler.getErrorMessage(
appException,
stringProvider
)
)
},
onApiError = { apiException ->
view?.showError(
ErrorHandler.getErrorMessage(
apiException,
stringProvider
)
)
},
onAuthenticationError = { requestxception ->
view?.showError(
ErrorHandler.getErrorMessage(
requestxception,
stringProvider
)
)
},
onShowProgress = {
if (it) {
view?.showProgress()
} else {
view?.hideProgress()
}
},
onSubscribed = {
disposable.add(it)
})
)
}
}
这是我的看法:
interface ProductCategoryActivityView {
fun showError(message: String)
fun showProgress()
fun hideProgress()
fun showdata ( data: ArrayList<CateogryResponse>)
}
这是我的适配器:
class CategoryAdapter(
private val data: List<CateogryResponse>,
private val listener: onItemClickListener
) : RecyclerView.Adapter<CategoryAdapter.ViewHolder>() {
private val items: MutableList<CardView>
init {
this.items = ArrayList()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val v = LayoutInflater.from(parent.context)
.inflate(R.layout.fragment_category_adapter, parent, false)
return ViewHolder(v)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.tvTitle.text = data[position].product
items.add(holder.card)
}
override fun getItemCount(): Int {
return data.size
}
inner class ViewHolder(itemView: View
) : RecyclerView.ViewHolder(itemView),
View.OnClickListener {
val tvTitle: TextView = itemView.featured_title
val card: CardView = itemView.CardView
init {
itemView.setOnClickListener(this)
}
override fun onClick(v: View?) {
val position: Int = adapterPosition
if (position != RecyclerView.NO_POSITION) {
listener.onItemClick(position)
}
}
}
interface onItemClickListener {
fun onItemClick(position: Int)
}
}
图片:
片段类别适配器:
android:id="@+id/CardView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
app:cardCornerRadius="2dp"
app:cardElevation="8dp">
<!-- We Will Add here the card & ImageViews -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="15dp">
<ImageView
android:id="@+id/featured_image"
android:layout_width="match_parent"
android:layout_height="140dp"
android:scaleType="centerCrop" />
<TextView
android:id="@+id/featured_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:lineHeight="23dp"
android:text="Chairs"
android:textColor="@color/colorAccent"
android:textSize="20sp" />
<TextView
android:id="@+id/featured_desc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="asbkd asudhlasn saudnas jasdjasl hisajdl asjdlnas" />
</LinearLayout>
</androidx.cardview.widget.CardView>
碎片产品类别:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#fafcfe"
tools:context="ui.category.ProductCategoryActivity">
<ImageView
android:id="@+id/imageView3"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/constraintLayout"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginTop="48dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/imageView"
app:layout_constraintTop_toTopOf="parent">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerViewPrimary"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="48dp"
android:layout_marginTop="20dp"
android:text="@string/topselling"
android:textSize="18sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/constraintLayout" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/constraintLayout2"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="32dp"
android:layout_marginLeft="32dp"
android:layout_marginTop="16dp"
app:layout_constraintBottom_toTopOf="@+id/imageView3"
app:layout_constraintEnd_toEndOf="@+id/constraintLayout"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerViewSecondary"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<ImageView
android:id="@+id/imageView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="32dp"
app:layout_constraintBottom_toBottomOf="@+id/imageView3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
/>
<TextView
android:id="@+id/textViewCategories"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="48dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="15dp"
android:text="@string/catogries"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="@+id/constraintLayout"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteX="39dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
不知道出了什么问题。如果有人可以指出或告诉我需要做什么才能在水平回收视图中显示数据,我会非常感激
解决方案
一旦你的 fetch 调用被执行,你应该更新你的回收器视图适配器,而不是在它结束之前。
修改您的fetchcatogries
声明,使其接受一个回调方法,该方法将在数据加载后执行。
此方法将接受一个列表对象作为参数,您将在您的管理中ProductCategoryActivity
填充RecyclerView
.
fun fetchcatogries(callback: (MutableList<CateogryResponse>) -> Unit) {
getCategoryUseCase.execute()
.observeOn(observeOnScheduler)
.subscribeOn(subscribeOnScheduler)
.subscribe(
SingleRequestSubscriber(
{ categories ->
callback(categories)
},
...
)
}
您现在可以像这样编辑您的onCreate
和showdata
方法ProductCategoryActivity
:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = FragmentProductCategoryBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
presenter.fetchcatogries { categories ->
showdata(categories as ArrayList<CateogryResponse>)
}
}
override fun showdata(data: ArrayList<CateogryResponse>) {
val layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
recyclerViewPrimary.layoutManager = layoutManager
recyclerViewPrimary.setHasFixedSize(true)
recyclerViewPrimary.adapter = CategoryAdapter(data.toList(), this)
}
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