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我从后端 API 获取项目列表，并在 Viewpager 中水平显示列表项目。列表已成功获取并显示在 ViewPager 中。但问题是，一开始滑动并不顺畅，有时会开始平滑滑动。如何从一开始就平滑滑动

我使用 Retrofit 和 rxjava 从服务器获取列表。我也用LiveData观察Fragment中viewModel的变量变化

TestimonialService.kt

@GET(Constants.API_TESTIMONIAL)
fun getAllTestimonial(): Flowable<Response<TestimonialResponse>>

WelcomeViewModel.kt

val uiState: MutableLiveData<Event<UiState<TestimonialResponse>>> = MutableLiveData()

fun getAllTestimonial() {
    compositeDisposable += testimonialService.getAllTestimonial()
        .performOnBackgroundOutputOnMain()
        .doOnSubscribe { uiState.value = Event(loading(true)) }
        .doOnTerminate { uiState.value = Event(loading(false)) }
        .subscribe({
            if (it.isSuccessful) {
                uiState.value = Event(success(it.body()!!)!!)
            } else {
                uiState.value = Event(alert(it.code().toString()))
            }
        }, {
            uiState.value = Event(failure(it))
        })
}

TestimonialAdapter.kt

class TestimonialAdapter: RecyclerView.Adapter<TestimonialViewHolder>() {

    var testimonialList: List<Testimonial>? = ArrayList()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): TestimonialViewHolder {
        val view = ItemTestimonialBinding.inflate(LayoutInflater.from(parent.context), parent, false)
        return TestimonialViewHolder(view)
    }

    override fun onBindViewHolder(holder: TestimonialViewHolder, position: Int) {
        holder.bind(testimonialList?.get(position)!!)
    }

    override fun getItemCount() = testimonialList?.size ?: 0

    fun notifyChanged(testimonialList: ArrayList<Testimonial>) {
        this.testimonialList = testimonialList
        notifyDataSetChanged()
    }

}

TestimonialViewHolder.kt

class TestimonialViewHolder(private val bindingView: ItemTestimonialBinding) : RecyclerView.ViewHolder(bindingView.root) {

    fun bind(testimonial: Testimonial) {
        bindingView.testimonial = testimonial
    }

}

item.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"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <import type="com.caretutors.api.serviceModel.testimonials.Testimonial"/>
        <variable name="testimonial" type="Testimonial" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <androidx.cardview.widget.CardView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="10dp"
            app:cardElevation="0dp"
            app:cardCornerRadius="@dimen/_22sdp">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:layout_gravity="center"
                android:padding="5dp">

                <ImageView
                    android:id="@+id/client_image_view"
                    android:layout_width="70dp"
                    android:layout_height="70dp"
                    android:layout_marginStart="5dp"
                    android:layout_gravity="center_vertical"
                    app:image="@{testimonial.photo}"
                    tools:src="@drawable/ic_round_avatar" />

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="10dp"
                    android:layout_marginEnd="10dp"
                    android:layout_marginBottom="5dp"
                    android:layout_marginTop="5dp"
                    android:orientation="vertical">

                    <TextView
                        android:id="@+id/name_text_view"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:ellipsize="end"
                        android:maxLines="1"
                        android:text="@{testimonial.name}"
                        tools:text="@string/john_doe"
                        android:textColor="@color/black_85_percent"
                        android:textSize="@dimen/fourteen_sp_text_size"
                        android:fontFamily="@font/inter_semi_bold"/>

                    <TextView
                        android:id="@+id/designation_text_view"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="-4dp"
                        android:ellipsize="end"
                        android:maxLines="1"
                        android:text="@{testimonial.designation}"
                        tools:text="@string/web_developer"
                        android:textColor="@color/dark_ash"
                        android:textSize="@dimen/twelve_sp_text_size" />

                    <ScrollView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="2dp"
                        android:fillViewport="true">

                        <TextView
                            android:id="@+id/comment_text_view"
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:justificationMode="inter_word"
                            android:ellipsize="end"
                            android:text="@{testimonial.comment}"
                            tools:text="@string/short_description"
                            android:textColor="@color/black_50_percent"
                            android:textSize="@dimen/eleven_sp_text_size" />

                    </ScrollView>

                </LinearLayout>

            </LinearLayout>

        </androidx.cardview.widget.CardView>

    </LinearLayout>

</layout>

fragment.welcome.xml

<androidx.viewpager2.widget.ViewPager2
            android:id="@+id/testimonial_view_pager"
            android:layout_width="match_parent"
            android:layout_height="@dimen/_110sdp"
            android:layout_alignParentBottom="true"
            android:layout_gravity="bottom"
            android:orientation="horizontal" />

WelcomeFragment.kt

override fun initWidget() {
    with(testimonial_view_pager) {
        adapter = testimonialAdapter
        offscreenPageLimit = 1
        setPageTransformer(CustomPageTransformer(context!!, R.dimen.testimonial_viewpager_visible_portion_of_next_item, R.dimen.testimonial_viewpager_current_item_horizontal_margin))
        addItemDecoration(CustomHorizontalMarginItemDecorator(context, R.dimen.testimonial_viewpager_current_item_horizontal_margin))
    }
}

override fun observeLiveData() {
    with(viewModel) {
        getAllTestimonial()

        uiState.observe(this@WelcomeFragment, Observer {
            it.getContentIfNotHandled()?.let { state ->
                when (state) {

                    is Progress -> {
                        with(shimmer_view_container) {
                            if (state.isLoading) {
                                startShimmer()
                            } else {
                                stopShimmer()
                                visibilityGone()
                            }
                        }
                    }

                    is Success -> {
                        val testimonialList = state.successInfo.data as ArrayList<Testimonial>
                        testimonialAdapter.notifyChanged(testimonialList)

                        AutoSlider(testimonial_view_pager, testimonialList.size).startAutoSlider()
                    }

                    is Alert -> context?.showToast(state.alert)

                    is Failure -> {
                        if (state.throwable is IOException) {
                            context?.showToast("Internet Connection Failed")
                        } else {
                            context?.showToast("Json Parsing Error")
                        }
                    }
                }
            }
        })
    }
}

AutoSlider.kt

class AutoSlider(private val viewPager: ViewPager2, private val totalItem: Int) {

private var runnable: Runnable? = null
private val handler = Handler()

init {
    runnable = Runnable {
        var position = viewPager.currentItem
        position += 1
        if (position >= totalItem) position = 0

        viewPager.currentItem = position
    }
}

fun startAutoSlider() {
    val swipeTimer = Timer()

    swipeTimer.schedule(object : TimerTask() {
        override fun run() {
            handler.post(runnable)
        }
    }, 3000, 3000)
}

}

最初滚动不流畅。但有时，它开始平滑滚动

4

1 回答 1

0 
class AutoSlider(private val viewPager: ViewPager2) {

    private var runnable: Runnable? = null
    private val handler = Handler()

    fun startAutoSlider(totalItem: Int) {
        runnable = Runnable {
            var position = viewPager.currentItem
            position += 1
            if (position >= totalItem) position = 0

            viewPager.currentItem = position
            handler.postDelayed(runnable, 10000)//remove this line
        }

        handler.postDelayed(runnable, 10000)
    }

你延迟两次，只需删除我提到的这一行

于 2019-11-05T10:46:17.633 回答