recyclerview中的广告 [英] Ads in recyclerview
本文介绍了recyclerview中的广告的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个在房间数据库中存储一些数据的应用程序.一开始，我的适配器是这样的:
I have an app that stores some data in room database. At first, my adapter was like that:
public class ViewCourseAdapter extends ListAdapter<Course, ViewCourseAdapter.ViewCourseHolder> {
private int previousPosition = 0;
public ViewCourseAdapter() {
super(DIFF_CALLBACK);
}
private static final DiffUtil.ItemCallback<Course> DIFF_CALLBACK = new DiffUtil.ItemCallback<Course>() {
@Override
public boolean areItemsTheSame(@NonNull Course oldItem, @NonNull Course newItem) {
return oldItem.getId() == newItem.getId();
}
@Override
public boolean areContentsTheSame(@NonNull Course oldItem, @NonNull Course newItem) {
return oldItem.getfName().equals(newItem.getfName());
}
};
@NonNull
@Override
public ViewCourseHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_courses_item, parent, false);
return new ViewCourseHolder(itemView);
}
@Override
public void onBindViewHolder(@NonNull ViewCourseHolder holder, int position) {
Course currentCourse = getItem(position);
String fullName = currentCourse.getfName() + " " + currentCourse.getlName();
SpannableString SfullName = new SpannableString(fullName);
SfullName.setSpan(new UnderlineSpan(), 0, fullName.length(), 0);
holder.text_view_firstName_1.setText(SfullName);
if (position > previousPosition) {
AnimationUtil.animate(holder, true);
} else {
AnimationUtil.animate(holder, false);
}
previousPosition = position;
}
class ViewCourseHolder extends RecyclerView.ViewHolder {
private TextView text_view_firstName_1;
ViewCourseHolder(@NonNull View itemView) {
super(itemView);
text_view_firstName_1 = itemView.findViewById(R.id.text_view_firstName_1);
}
}
@Override
public int getItemCount() {
return super.getItemCount();
}
一切正常.现在，我想在recyclerview中展示广告，所以我更改了适配器:
And everything was working perfect. Now I want to show ads inside recyclerview, so I changed my adapter:
public class ViewCourseAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int COURSE_VIEW_TYPE = 0;
private static final int AD_VIEW_TYPE = 1;
private List<Course> data;
private List<Object> ad;
private Context context;
private LayoutInflater layoutInflater;
private int previousPosition = 0;
public ViewCourseAdapter(Context context, List<Object> ad) {
this.data = new ArrayList<>();
this.context = context;
this.layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.ad = ad;
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
switch (viewType ) {
case COURSE_VIEW_TYPE:
View courseView = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_courses_item, parent, false);
return new ViewCourseViewHolder(courseView);
case AD_VIEW_TYPE:
default:
View adView = LayoutInflater.from(parent.getContext()).inflate(R.layout.native_ads, parent, false);
return new AdViewHolder(adView);
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
int viewType = getItemViewType(position);
switch (viewType) {
case COURSE_VIEW_TYPE:
ViewCourseViewHolder holder1 = (ViewCourseViewHolder) holder;
Course currentCourse = (Course) data.get(position);
String fullName = currentCourse.getfName() + " " + currentCourse.getlName();
SpannableString SfullName = new SpannableString(fullName);
SfullName.setSpan(new UnderlineSpan(), 0, fullName.length(), 0);
holder1.text_view_firstName_1.setText(SfullName);
break;
case AD_VIEW_TYPE:
default:
AdViewHolder bannerHolder = (AdViewHolder) holder;
AdView adView = (AdView) ad.get(position);
ViewGroup adCardView = (ViewGroup) bannerHolder.itemView;
if (adCardView.getChildCount() > 0) {
adCardView.removeAllViews();
}
if (adView.getParent() != null) {
((ViewGroup) adView.getParent()).removeView(adView);
}
adCardView.addView(adView);
}
if (position > previousPosition) {
AnimationUtil.animate(holder, true);
} else {
AnimationUtil.animate(holder, false);
}
previousPosition = position;
}
class AdViewHolder extends RecyclerView.ViewHolder {
AdViewHolder(View view) {
super(view);
}
}
@Override
public int getItemViewType(int position) {
return (position % ViewCoursesActivity.ITEMS_PER_AD == 0) ? AD_VIEW_TYPE
: COURSE_VIEW_TYPE;
}
@Override
public int getItemCount() {
return data.size();
}
public void setData(List<Course> newData) {
if (data != null) {
CourseDiffCallback courseDiffCallback = new CourseDiffCallback(data, newData);
DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(courseDiffCallback);
data.clear();
data.addAll(newData);
diffResult.dispatchUpdatesTo(this);
} else {
data = newData;
}
}
public class ViewCourseViewHolder extends RecyclerView.ViewHolder {
private TextView text_view_firstName_1;
ViewCourseViewHolder(@NonNull View itemView) {
super(itemView);
text_view_firstName_1 = itemView.findViewById(R.id.text_view_firstName_1);
}
}
private class CourseDiffCallback extends DiffUtil.Callback {
private final List<Course> oldItem, newItem;
private CourseDiffCallback(List<Course> oldItem, List<Course> newItem) {
this.oldItem = oldItem;
this.newItem = newItem;
}
@Override
public int getOldListSize() {
return oldItem.size();
}
@Override
public int getNewListSize() {
return newItem.size();
}
@Override
public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
return oldItem.get(oldItemPosition).getId() == newItem.get(newItemPosition).getId();
}
@Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
return oldItem.get(oldItemPosition).getfName().equals(newItem.get(newItemPosition).getfName());
}
}
我的活动是:
public class ViewCoursesActivity extends AppCompatActivity {
private CourseViewModel courseViewModel;
// A banner ad is placed in every 8th position in the RecyclerView.
public static final int ITEMS_PER_AD = 8;
private static final String AD_UNIT_ID = "ca-app-pub-3940256099942544/6300978111";
// The RecyclerView that holds and displays banner ads and menu items.
private RecyclerView recyclerView;
// List of banner ads and MenuItems that populate the RecyclerView.
private List<Object> data = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_courses);
recyclerView = findViewById(R.id.recycler_view_3);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
addBannerAds();
loadBannerAds();
final ViewCourseAdapter adapter = new ViewCourseAdapter(this, data);
recyclerView.setAdapter(adapter);
courseViewModel = ViewModelProviders.of(this).get(CourseViewModel.class);
courseViewModel.setIdForCourse(0);
//courseViewModel.getCourseByStudentId().observe(this, adapter::submitList);
courseViewModel.getCourseByStudentId().observe(this, adapter::setData);
}
@Override
protected void onResume() {
for (Object item : data) {
if (item instanceof AdView) {
AdView adView = (AdView) item;
adView.resume();
}
}
super.onResume();
}
@Override
protected void onPause() {
for (Object item : data) {
if (item instanceof AdView) {
AdView adView = (AdView) item;
adView.pause();
}
}
super.onPause();
}
@Override
protected void onDestroy() {
for (Object item : data) {
if (item instanceof AdView) {
AdView adView = (AdView) item;
adView.destroy();
}
}
super.onDestroy();
}
/**
* Adds banner ads to the items list.
*/
private void addBannerAds() {
// Loop through the items array and place a new banner ad in every ith position in
// the items List.
for (int i = 0; i <= data.size(); i += ITEMS_PER_AD) {
final AdView adView = new AdView(ViewCoursesActivity.this);
adView.setAdSize(AdSize.SMART_BANNER);
adView.setAdUnitId(AD_UNIT_ID);
data.add(i, adView);
}
}
/**
* Sets up and loads the banner ads.
*/
private void loadBannerAds() {
// Load the first banner ad in the items list (subsequent ads will be loaded automatically
// in sequence).
loadBannerAd(0);
}
/**
* Loads the banner ads in the items list.
*/
private void loadBannerAd(final int index) {
if (index >= data.size()) {
return;
}
Object item = data.get(index);
if (!(item instanceof AdView)) {
throw new ClassCastException("Expected item at index " + index + " to be a banner ad"
+ " ad.");
}
final AdView adView = (AdView) item;
// Set an AdListener on the AdView to wait for the previous banner ad
// to finish loading before loading the next ad in the items list.
adView.setAdListener(new AdListener() {
@Override
public void onAdLoaded() {
super.onAdLoaded();
// The previous banner ad loaded successfully, call this method again to
// load the next ad in the items list.
loadBannerAd(index + ITEMS_PER_AD);
}
@Override
public void onAdFailedToLoad(int errorCode) {
// The previous banner ad failed to load. Call this method again to load
// the next ad in the items list.
Log.e("ViewCoursesActivity", "The previous banner ad failed to load. Attempting to"
+ " load the next banner ad in the items list.");
loadBannerAd(index + ITEMS_PER_AD);
}
});
// Load the banner ad.
adView.loadAd(new AdRequest.Builder().build());
}
此后，我有两个问题: 1.在第一位置显示的是广告，而不是我的数据库中的第一项，而第一项无处.如果我检查数据库中的第一项，则不会出现在recyclerview中. 2.如果我要滚动项目，则应用程序崩溃，错误是"java.lang.IndexOutOfBoundsException:索引:8，大小:1". 我究竟做错了什么? 请帮我.谢谢！
After that I have two problems: 1. At frist position it display an ad instead of first item from my database, and first item is nowhere. If I check my database first item is there, just not apear in recyclerview. 2. If I want to scroll items, the app crash, and the error is "java.lang.IndexOutOfBoundsException: Index: 8, Size: 1". What am I doing wrong? Please help me. Thank you!
推荐答案
从根本上讲，RecyclerView用于向用户显示List.用它来指导您的实施.
Fundamentally, a RecyclerView is used to display a List to the user. Use this to guide your implementation.
当前，您有两个列表:
private List<Course> data;
private List<Object> ad;
您需要找到一种方法可以将这些整理"到单个列表中.也许是这样的:
You need to find a way to "collate" these down to a single list. Maybe something like this:
private static List<Object> collate(List<Course> data, List<Object> ads) {
List<Object> collated = new ArrayList<>();
while (data.size() > 0 || ads.size() > 0) {
for (int i = 0; i < ITEMS_PER_AD && data.size() > 0; ++i) {
collated.add(data.remove(0));
}
if (ads.size() > 0) {
collated.add(ads.remove(0));
}
}
return collated;
}
定义了该方法后，您可以替换现有的构造函数:
With that method defined, you can replace your existing constructor:
private List<Course> data;
private List<Object> ad;
// ...
public ViewCourseAdapter(Context context, List<Object> ad) {
this.data = new ArrayList<>();
this.ad = ad;
// ...
}
与此:
private List<Object> ad;
private List<Object> collated;
// ...
public ViewCourseAdapter(Context context, List<Object> ad) {
this.ad = ad;
this.collated = new ArrayList<>(ad);
// ...
}
您可以替换现有的setData()方法:
And you can replace your existing setData() method:
public void setData(List<Course> newData) {
if (data != null) {
CourseDiffCallback courseDiffCallback = new CourseDiffCallback(data, newData);
DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(courseDiffCallback);
data.clear();
data.addAll(newData);
diffResult.dispatchUpdatesTo(this);
} else {
data = newData;
}
}
与此:
public void setData(List<Course> newData) {
if (data != null) {
List<Object> newCollated = collate(ad, newData);
// setup DiffUtil callback here...
this.collated = newCollated;
// dispatch DiffUtil result here...
}
}
现在，您将有一个单个列表，可以在适配器中使用.然后，您可以更改适配器的方法以使用该列表:
Now you will have a single list that you can use in your adapter. Then you can change your adapter's methods to use that one list:
@Override
public int getItemCount() {
return collated.size();
}
@Override
public int getItemViewType(int position) {
return (collated.get(position) instanceof Course)
? COURSE_VIEW_TYPE
: AD_VIEW_TYPE;
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
if (holder.getItemViewType() == COURSE_VIEW_TYPE) {
bindCourseHolder((ViewCourseViewHolder) holder, position);
} else if (holder.getItemViewType() == AD_VIEW_TYPE) {
bindAdHolder((AdViewHolder) holder, position);
}
}
private void bindCourseHolder(ViewCourseViewHolder holder, int position) {
// ...
}
private void bindAdHolder(AdViewHolder holder, int position) {
// ...
}
所有这些更改都基于一个基本概念，即您只有一个列表，并且该列表(可能)包含许多不同类型的事物.
All of these changes are based on the fundamental concept that you just have a single list, and that list holds (potentially) many different types of things.
这篇关于recyclerview中的广告的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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