如何实时修改View-pager
如何实时修改View-pager
提问于 2019-12-21 00:16:50
我，是android的新手。我创建了一个从firebase获取图像的视图分页程序。它工作得很好。但是在视图分页中有一些漏洞，我没能解决。
1)我的View-pager没有实时更新。意味着每当我修改firebase中的图像时。它在实时的基础上不起作用。我必须关闭我的应用程序，然后必须重新启动它才能看到这些更新。
2)当我从firebase中的列表中删除项目时。我的应用程序崩溃了，在Logcat中抛出了这个异常。
java.lang.IndexOutOfBoundsException: Index: -1, Size: 5
at java.util.ArrayList.add(ArrayList.java:483)
at com.release.pack.lootbox.Fragments.HomeFragment$7.onEvent(HomeFragment.java:294)
at com.release.pack.lootbox.Fragments.HomeFragment$7.onEvent(HomeFragment.java:281)下面是我的代码：
滑块图像适配器：
public class SliderImageAdapter extends SliderViewAdapter<SliderImageAdapter.SliderAdapterVH> {
public List<Banner> bannerList;
public Context context;
public SliderImageAdapter(Context context, List<Banner> bannerList) {
this.bannerList = bannerList;
this.context = context;
}
@Override
public SliderAdapterVH onCreateViewHolder(ViewGroup parent) {
View inflate = LayoutInflater.from(parent.getContext()).inflate(R.layout.image_slider_myshop, parent, false);
return new SliderAdapterVH(inflate);
}
@Override
public void onBindViewHolder(final SliderAdapterVH viewHolder, final int position) {
Glide.with(viewHolder.itemView)
.load(bannerList.get(position).getmSliderImage())
.fitCenter()
.into(viewHolder.imageViewBackground);
}
@Override
public int getCount() {
return bannerList.size();
}
class SliderAdapterVH extends SliderViewAdapter.ViewHolder {
View itemView;
ImageView imageViewBackground;
ImageView imageGifContainer;
TextView textViewDescription;
public ProgressBar progressBar;
public ImageView imageViewFailed;
public SliderAdapterVH(View itemView) {
super(itemView);
imageViewBackground = itemView.findViewById(R.id.iv_auto_image_slider);
imageGifContainer = itemView.findViewById(R.id.iv_gif_container);
textViewDescription = itemView.findViewById(R.id.tv_auto_image_slider);
progressBar = itemView.findViewById(R.id.featured_deal_progress);
imageViewFailed = itemView.findViewById(R.id.featured_deal_img_failed_to_load);
this.itemView = itemView;
}
}
}主页片段：
private SliderImageAdapter sliderImageAdapter;
private List<Banner> bannerList;
bannerList = new ArrayList<>();
sliderImageAdapter = new SliderImageAdapter(getActivity(),bannerList);
sliderMyshop = view.findViewById(R.id.imageSlider);
sliderMyshop.setSliderAdapter(sliderImageAdapter);
sliderMyshop.setIndicatorAnimation(IndicatorAnimations.WORM); //set indicator animation by using SliderLayout.IndicatorAnimations. :WORM or THIN_WORM or COLOR or DROP or FILL or NONE or SCALE or SCALE_DOWN or SLIDE and SWAP!!
sliderMyshop.setSliderTransformAnimation(SliderAnimations.SIMPLETRANSFORMATION);
sliderMyshop.setIndicatorSelectedColor(Color.WHITE);
sliderMyshop.setIndicatorUnselectedColor(Color.GRAY);
sliderMyshop.startAutoCycle();
mFirestore.collection("Banner").orderBy("priority", Query.Direction.DESCENDING).addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@javax.annotation.Nullable QuerySnapshot documentSnapshots, @javax.annotation.Nullable FirebaseFirestoreException e) {
if (e != null) {
Log.d(TAG, "Error : " + e.getMessage());
}
assert documentSnapshots != null;
for (DocumentChange doc : documentSnapshots.getDocumentChanges()) {
if (doc.getType() == DocumentChange.Type.ADDED) {
String doc_id = doc.getDocument().getId();
Banner banner = doc.getDocument().toObject(Banner.class).withDocId(doc_id);
bannerList.add(doc.getNewIndex(), banner);
sliderImageAdapter.notifyDataSetChanged();
} else if (doc.getType() == DocumentChange.Type.MODIFIED) {
String docID = doc.getDocument().getId();
Banner changedModel = doc.getDocument().toObject(Banner.class).withDocId(docID);
if (doc.getOldIndex() == doc.getNewIndex()) {
// Item changed but remained in same position
bannerList.set(doc.getOldIndex(), changedModel);
// sliderImageAdapter.notifyItemChanged(doc.getOldIndex());
} else {
// Item changed and changed position
bannerList.remove(doc.getOldIndex());
bannerList.add(doc.getNewIndex(), changedModel);
// sliderImageAdapter.notifyItemMoved(doc.getOldIndex(), doc.getNewIndex());
}
} else if (doc.getType() == DocumentChange.Type.REMOVED) {
// remove
bannerList.remove(doc.getOldIndex());
// sliderImageAdapter.notifyItemRemoved(doc.getOldIndex());
}
}
}
});当我在firebase中添加新图像时，它会实时更新。但当我在我的图像中做修改时就不会了。或者从我的列表中删除该项目。
回答 1
Stack Overflow用户
发布于 2019-12-21 00:34:27
崩溃
bannerList.add(doc.getNewIndex(), banner);这一行是IndexOutOfBoundsException.的原因
(java.lang.IndexOutOfBoundsException: Index: -1, Size: 5)doc.getNewIndex()正在返回-1。列表不能接受-1作为索引。所以请检查你的doc.getNewIndex()。
用于实时更新的
bannerList.clear();在for循环之前添加此代码，否则将添加冗余数据，并且无法更新新的更改。
参见this：每次查询结果发生变化(即添加、删除或修改文档时)，快照处理程序都会收到一个新的查询快照。
对于每个更改，将获取整个集合的
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/59428359
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