我在显示进度栏上遇到问题，无法为用户提供有关应用程序正在加载要显示的新数据的信息。我已经看了看很多有关它的解决方案。我在加载和显示新数据方面相当成功。但是显示进度条并不是真的成功。寻找为什么我的代码错误或我的错误在哪里真令人沮丧。所以在这里，我需要这个领域的一些专家的帮助。
我已经使用了在互联网上找到的所有内容。当它到达列表的底部时，我正在输入文字。但是，当我调试程序时，键入返回数字以显示进度条未调用。
这是我的适配器的重要部分：
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
if (i == 1) {
header = false;
return new NewsViewHolder(LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_news, viewGroup, false));
} else if (i == 2) {
Log.d("END", "Bagian terakhir");
return new LoadingViewHolder(LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_progress, viewGroup, false));
} else {
header = true;
return new NewsGroupViewHolder(LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_group, viewGroup, false));
}
}
@Override
public int getItemViewType(int position) {
if (position > 0 && articleList.get(position).getPublishedAt().equals(articleList.get(abs(position - 1)).getPublishedAt())) {
return 1;
}
else if(articleList.get(position) == null){
return 2;
}
else {
return 0;
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
if (viewHolder instanceof NewsViewHolder) {
NewsViewHolder newsViewHolder = (NewsViewHolder) viewHolder;
newsViewHolder.bind(articleList.get(i));
} else if (viewHolder instanceof LoadingViewHolder) {
LoadingViewHolder loadingViewHolder = (LoadingViewHolder) viewHolder;
loadingViewHolder.progressBar.setIndeterminate(true);
} else if (viewHolder instanceof NewsGroupViewHolder) {
NewsGroupViewHolder newsGroupViewHolder = (NewsGroupViewHolder) viewHolder;
newsGroupViewHolder.bind(listDate.get(i), articleList.get(i));
}
}
以下是我在MainActivity中加载数据的方式：
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
if(newsPresenter.isListItemDisplaying(recyclerView) && !newsAdapter.isSearching()){
// if(loadMore!=null){
// loadMore.onLoadMore();
// }
allArticle.add(null);
newsAdapter.notifyItemInserted(allArticle.size()-1);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
allArticle.remove(allArticle.size()-1);
newsAdapter.notifyItemRemoved(allArticle.size());
Log.d("LAST_ITEM","loadmore "+totalPages);
totalPages++;
List<Article> newArticle = new ArrayList<>();
newArticle.addAll(newsPresenter.loadEverything("android&page="+totalPages));
isLoading = true;
}
},PERIOD_MS);
}
}
});
还有一些代码来确定我是否到达RecyclerView的结尾：
public boolean isListItemDisplaying(RecyclerView recyclerView){
if(recyclerView.getAdapter().getItemCount()!=0){
int lastVisibleItemPosition = ((LinearLayoutManager)recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
if(lastVisibleItemPosition!=RecyclerView.NO_POSITION && lastVisibleItemPosition == recyclerView.getAdapter().getItemCount()-1){
return true;
}
}
return false;
}
下面是ProgressBar的XML文件：
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize">
<ProgressBar
android:id="@+id/progressBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:foregroundGravity="center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
这是我用于MainActivity的XML文件的一部分：
<RelativeLayout
android:layout_width="match_parent"
android:id="@+id/relative_slider"
android:layout_height="150dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<android.support.v4.view.ViewPager
android:id="@+id/headline_vp"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<me.relex.circleindicator.CircleIndicator
android:layout_width="match_parent"
android:id="@+id/indicator"
android:layout_height="48dp"
android:layout_alignBottom="@+id/headline_vp"
android:layout_alignParentStart="true"/>
</RelativeLayout>
<com.tokopedia.testproject.problems.news.view.VerticalRecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:clipToPadding="false"
app:layout_constrainedHeight="true"
android:padding="16dp"
android:visibility="gone"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/relative_slider"
app:layout_constraintVertical_bias="0.0" />
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/refresh_news"
android:layout_width="390dp"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
android:visibility="gone"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0">
</android.support.v4.widget.SwipeRefreshLayout>
我希望进度条在每次到达recyclerview底部时显示。感谢您的时间和帮助。问我是否需要一些解释。