双击第一次加载后，Android RecyclerView 第一个和最后一个项目点击有效

【问题标题】：Android RecyclerView First and Last Item click works after Double click on First load双击第一次加载后，Android RecyclerView 第一个和最后一个项目点击有效
【发布时间】：2020-12-23 16:33:28
【问题描述】：

我有一个recyclerview。它在onCreateViewHolder 方法中有项目点击事件，在onBindViewHolder 方法中有一个imageview 点击事件。令人惊讶的是，当 recyclerview 第一次加载first and last item click 在第二次点击后工作，然后在每次点击后如果它没有滚动。再次当我滚动 recyclerview 时，第一个和最后一个项目也会发生同样的情况，就像第一次加载一样。我不知道是什么问题

下面是我的recyclerview布局@+id/recyclerViewForFilteredCourses是recyclerview

    <androidx.coordinatorlayout.widget.CoordinatorLayout 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"
    tools:context=".Activities.CoursesActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <include layout="@layout/toolbar_with_search"
            android:id="@+id/toolbar" />

        <com.github.ybq.android.spinkit.SpinKitView
            xmlns:app="http://schemas.android.com/apk/res-auto"
            android:id="@+id/progressBar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:layout_centerHorizontal="true"
            app:SpinKit_Color="@color/textColorGrey"
            android:visibility="gone"
            android:elevation="200dp"
            style="@style/SpinKitView.Circle"/>

        <!--This textview and the recycler view is responsible for filtered course section-->
        <TextView
            android:id="@+id/filterResultTitle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Showing X Courses"
            android:layout_below="@+id/toolbar"
            style="@style/headerTitleLabel"/>

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerViewForFilteredCourses"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/filterResultTitle"
            android:layout_above="@+id/bottomNavigationView"
            android:paddingHorizontal="14dp"
            android:clipToPadding="false"
            android:layout_marginTop="10dp"
            android:overScrollMode="never"/>

        <!--This is the floating filter button-->
        <com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id="@+id/floatingFilterButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:clickable="true"
            android:layout_alignParentRight="true"
            android:layout_marginRight="25dp"
            android:layout_marginBottom="25dp"
            android:layout_alignParentBottom="true"
            android:backgroundTint="#273647"
            android:elevation="6dp"
            app:fabSize="normal"
            app:borderWidth="0dp"
            android:src="@drawable/filter"
            android:onClick="handleFilterButton" />
    </RelativeLayout>

    <androidx.core.widget.NestedScrollView
        android:id="@+id/bottomSheet"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#FEFFFF"
        app:layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior"
        app:behavior_hideable="true"
        app:behavior_peekHeight = "0dp">
        <include layout="@layout/course_filter_page" />
    </androidx.core.widget.NestedScrollView>

    </androidx.coordinatorlayout.widget.CoordinatorLayout>

下面是我的 onCreateVieHolder 项目点击

    public CoursesAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.course_cell2, parent, false);
        final ViewHolder holder = new ViewHolder(view);
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                final Course currentCourse = mCourses.get(holder.getAdapterPosition());
                switchToCourseDetailsActivity(currentCourse);
            }
        });
        return holder;
    }

    private void switchToCourseDetailsActivity(Course currentCourse) {
        Intent intent = new Intent(mContext, CourseDetailsActivity .class);
        intent.putExtra("Course", currentCourse);
        mContext.startActivity(intent);
    }

下面是我完整的onBindViewHolder

public class CoursesAdapter extends RecyclerView.Adapter<CoursesAdapter.ViewHolder> {
private static final String TAG = "Courses List Adapter";
private static final String TAG2 = "Checker";

//vars
private Context mContext;
private ArrayList<Course> mCourses = new ArrayList<>();

Matcher matcher;

public CoursesAdapter(Context context, ArrayList<Course> courses) {
    mCourses = courses;
    mContext = context;

}


@NonNull
@Override
public CoursesAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.course_cell2, parent, false);
    final ViewHolder holder = new ViewHolder(view);
    return holder;
     }

 private void switchToCourseDetailsActivity(Course currentCourse) {
    Intent intent = new Intent(mContext, CourseDetailsActivity .class);
    intent.putExtra("Course", currentCourse);
    mContext.startActivity(intent);
}


@Override
public void onBindViewHolder(@NonNull final CoursesAdapter.ViewHolder holder, final int position) {
    final Course currentCourse = mCourses.get(position);

    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            switchToCourseDetailsActivity(currentCourse);
        }
    });


    holder.name.setText(currentCourse.getTitle());
   // holder.coursePrice.setText(currentCourse.getPrice());
    holder.totalNumberOfRating.setText("( "+currentCourse.getTotalNumberRating()+" )");
    //holder.instructorName.setText("by "+currentCourse.getInstructor()+" "+currentCourse.getBiography());
    holder.starRating.setRating(currentCourse.getRating());
    holder.rating.setText((" "+currentCourse.getRating()+" "));

    if(currentCourse.getIs_bestseller().equals("yes")){
        holder.tvBestseller.setVisibility(View.VISIBLE);
    }else{
        holder.tvBestseller.setVisibility(View.GONE);
    }

    if(currentCourse.getCourseOverviewUrl()!=null && currentCourse.getCourseOverviewProvider()!=null && currentCourse.getCourseOverviewProvider().equals("youtube")){

        //Extract video id from url
        String pattern = "(?<=watch\\?v=|/videos/|embed\\/|youtu.be\\/|\\/v\\/|\\/e\\/|watch\\?v%3D|watch\\?feature=player_embedded&v=|%2Fvideos%2F|embed%\u200C\u200B2F|youtu.be%2F|%2Fv%2F)[^#\\&\\?\\n]*";

        Pattern compiledPattern = Pattern.compile(pattern);
        matcher = compiledPattern.matcher(currentCourse.getCourseOverviewUrl()); //url is youtube url for which you want to extract the id.

        if (matcher.find()) {
                holder.play_video.setVisibility(View.VISIBLE);
                holder.play_video1.setVisibility(View.VISIBLE);

        } else{
            holder.play_video.setVisibility(View.GONE);
            holder.play_video1.setVisibility(View.GONE);
        }


    } else{
        holder.play_video.setVisibility(View.GONE);
        holder.play_video1.setVisibility(View.GONE);
    }


    holder.play_video.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            final BottomSheetDialog dialog3 = new BottomSheetDialog(mContext);
            dialog3.setContentView(R.layout.bottom_videoplay);
            if(!dialog3.isShowing()) {
                dialog3.show();
            }
            dialog3.setCancelable(true);
            final WebView web_view = (WebView) dialog3.findViewById(R.id.youtube_web_view);
            final ProgressBar progressBar2 = (ProgressBar) dialog3.findViewById(R.id.progressBar2);
            final TextView tvTitle2 = (TextView) dialog3.findViewById(R.id.tvTitle2);
            final TextView tvEnroll = (TextView) dialog3.findViewById(R.id.tvEnroll);
            tvTitle2.setText(currentCourse.getTitle());

            tvEnroll.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    switchToCourseDetailsActivity(currentCourse);
                }
            });

            //String myVideoYoutubeId = "Wwy9aibAd54";
            String myVideoYoutubeId;
            WebSettings webSettings = web_view.getSettings();
            webSettings.setJavaScriptEnabled(true);
            webSettings.setLoadWithOverviewMode(true);
            webSettings.setUseWideViewPort(true);

            myVideoYoutubeId=matcher.group();
            web_view.loadUrl("https://www.youtube.com/embed/" + myVideoYoutubeId);


            web_view.setWebViewClient(new WebViewClient() {
                @Override
                public boolean shouldOverrideUrlLoading(WebView view, String url) {
                    return false;
                }
            });

            web_view.setWebViewClient(new WebViewClient() {

                @Override
                public void onPageStarted(WebView view, String url, Bitmap favicon) {
                    super.onPageStarted(view, url, favicon);
                    progressBar2.setVisibility(View.VISIBLE);
                }

                @Override
                public void onPageFinished(WebView view, String url) {
                    super.onPageFinished(view, url);
                    progressBar2.setVisibility(View.GONE);

                    //to enable autoplay ref:https://stackoverflow.com/questions/28039209/android-webview-youtube-embed-video-autoplay-not-working/45655979#45655979
                    long delta = 100;
                    long downTime = SystemClock.uptimeMillis();
                    float x = view.getLeft() + (view.getWidth()/2);
                    float y = view.getTop() + (view.getHeight()/2);

                    MotionEvent tapDownEvent = MotionEvent.obtain(downTime, downTime + delta, MotionEvent.ACTION_DOWN, x, y, 0);
                    tapDownEvent.setSource(InputDevice.SOURCE_CLASS_POINTER);
                    MotionEvent tapUpEvent = MotionEvent.obtain(downTime, downTime + delta + 2, MotionEvent.ACTION_UP, x, y, 0);
                    tapUpEvent.setSource(InputDevice.SOURCE_CLASS_POINTER);

                    view.dispatchTouchEvent(tapDownEvent);
                    view.dispatchTouchEvent(tapUpEvent);

                }

            });


        }
    });

    holder.play_video1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            holder.play_video.performClick();
        }
    });

    if(currentCourse.getIs_mentor()!=null && currentCourse.getIs_mentor().equals("1")){
        holder.instructorName.setVisibility(View.VISIBLE);
        holder.tvMentor.setVisibility(View.GONE);

        if(currentCourse.getBiography()!=null) {
            holder.instructorName.setText("by " + currentCourse.getInstructor() + " " + currentCourse.getBiography());
        }else{
            holder.instructorName.setText("by " + currentCourse.getInstructor());
        }


    } else{
        //holder.tvMentor.setVisibility(View.GONE);
        holder.instructorName.setVisibility(View.GONE);
        holder.tvMentor.setVisibility(View.VISIBLE);

        if(currentCourse.getBiography()!=null) {
            holder.tvMentor.setText("by " + currentCourse.getInstructor() + " " + currentCourse.getBiography());
        } else{
            holder.tvMentor.setText("by " + currentCourse.getInstructor());
        }
    }


  if(currentCourse.getMain_price()!=null && !currentCourse.getPrice().equals("Free")){
        String  c_price = currentCourse.getPrice().substring(0, currentCourse.getPrice().length() - 1);
        Double main_price=Double.parseDouble(currentCourse.getMain_price());
        Double current_price=Double.parseDouble(c_price);

        if(current_price<main_price){
            holder.tvcompare.setVisibility(View.VISIBLE);
            holder.tvDiscountprice.setVisibility(View.VISIBLE);
            holder.tvDiscountprice.setText(Double.toString(main_price)+"Tk");

            Double diff=main_price-current_price;
            Double percent=diff*100/main_price;
            holder.tvcompare.setText(percent+"% OFF");

        }else{
            holder.tvDiscountprice.setVisibility(View.GONE);
            holder.tvcompare.setVisibility(View.GONE);
        }
    } else{
      holder.tvcompare.setVisibility(View.GONE);
      holder.tvDiscountprice.setVisibility(View.GONE);
  }

    if(!currentCourse.getPrice().equals("Free")) {
        String c_price = currentCourse.getPrice().substring(0, currentCourse.getPrice().length() - 1);
        holder.coursePrice.setText(c_price + "Tk");
    } else{
        holder.coursePrice.setText(currentCourse.getPrice());
    }



    if(currentCourse.getCourse_type()!=null){

        if(currentCourse.getCourse_type().equals("Course")){
            holder.tvCategory.setText("Lifetime Access");
            holder.image.setVisibility(View.VISIBLE);
            holder.play_video.setVisibility(View.VISIBLE);
            holder.monthly_couching.setVisibility(View.GONE);

            Glide.with(mContext)
                    .asBitmap()
                    .load(currentCourse.getThumbnail())
                    .into(holder.image);

        }

        if (currentCourse.getCourse_type().equals("MonthlyCouching")){
            holder.tvCategory.setText("Monthly Couching");
            holder.coursePrice.setText(holder.coursePrice.getText()+"/month");
            holder.image.setVisibility(View.GONE);
            holder.play_video.setVisibility(View.GONE);
            holder.monthly_couching.setVisibility(View.VISIBLE);
            Picasso.get().load(currentCourse.getThumbnail()).into(holder.image);
            Picasso.get().load(currentCourse.getThumbnail()).into(holder.image1);

            if(currentCourse.getOnline_classschedule()!=null){
                holder.layout_classschedule.setVisibility(View.VISIBLE);
                holder.tvClass_schedule.setText(currentCourse.getOnline_classschedule());
            } else{
                holder.layout_classschedule.setVisibility(View.GONE);
            }

        }

        if(currentCourse.getCourse_type().equals("FixedTermCouching")){

            holder.image.setVisibility(View.GONE);
            holder.play_video.setVisibility(View.GONE);
            holder.monthly_couching.setVisibility(View.VISIBLE);

            if(currentCourse.getDuration()!=null && currentCourse.getStart_date()!=null){

                long l = Long.parseLong(currentCourse.getStart_date());
                Date date = new Date(l);
                holder.tvCategory.setText(currentCourse.getDuration()+" Couching starting on "+date);
            }

            if(currentCourse.getOnline_classschedule()!=null){
                holder.layout_classschedule.setVisibility(View.VISIBLE);
                holder.tvClass_schedule.setText(currentCourse.getOnline_classschedule());
            } else{
                holder.layout_classschedule.setVisibility(View.GONE);
            }

        }

        if(currentCourse.getCourse_type().equals("Workshop")){

            holder.image.setVisibility(View.VISIBLE);
            holder.play_video.setVisibility(View.VISIBLE);
            holder.monthly_couching.setVisibility(View.GONE);

            if(currentCourse.getDuration()!=null && currentCourse.getStart_date()!=null){

                long l = Long.parseLong(currentCourse.getStart_date());
                Date date = new Date(l);
                holder.tvCategory.setText(currentCourse.getDuration()+" workshop starting on "+date);
            }
        }

    }


    if(currentCourse.getWeekly_class()!=null && currentCourse.getWeekly_class().equals("1")){
        holder.tvweekly_class.setVisibility(View.VISIBLE);

        if(currentCourse.getWeeklyonline_class()!=null && Integer.parseInt(currentCourse.getWeeklyonline_class())>0){
            holder.tvweekly_class.setText(holder.tvweekly_class.getText()+" "+currentCourse.getWeeklyonline_class());
        }

    } else{holder.tvweekly_class.setVisibility(View.GONE);}

    if(currentCourse.getWeekly_exam()!=null && currentCourse.getWeekly_exam().equals("1")){
        holder.tvweekly_exam.setVisibility(View.VISIBLE);

        if(currentCourse.getWeeklyonline_test()!=null && Integer.parseInt(currentCourse.getWeeklyonline_test())>0){
            holder.tvweekly_exam.setText(holder.tvweekly_exam.getText()+" "+currentCourse.getWeeklyonline_test());
        }

    } else{holder.tvweekly_exam.setVisibility(View.GONE);}

    if(currentCourse.getReview_class()!=null && currentCourse.getReview_class().equals("1")){
        holder.tvreview_class.setVisibility(View.VISIBLE);
    } else{holder.tvreview_class.setVisibility(View.GONE);}

    if(currentCourse.getCourse_upload()!=null && currentCourse.getCourse_upload().equals("1")){
        holder.tvcourse_upload.setVisibility(View.VISIBLE);
    } else{holder.tvcourse_upload.setVisibility(View.GONE);}

    if(currentCourse.getRecord_upload()!=null && currentCourse.getRecord_upload().equals("1")){
        holder.tvrecord_upload.setVisibility(View.VISIBLE);
    } else{holder.tvrecord_upload.setVisibility(View.GONE);}

    if(currentCourse.getCourse_type()!=null && currentCourse.getCourse_type().equals("FixedTermCouching") && currentCourse.getLifetime_access()!=null && currentCourse.getLifetime_access().equals("1")){
        holder.tvlifetime_access.setVisibility(View.VISIBLE);
    } else{holder.tvlifetime_access.setVisibility(View.GONE);}

}

@Override
public int getItemCount() {
    return mCourses.size();
}



public class ViewHolder extends RecyclerView.ViewHolder{

    ImageView image,image1,play_video,play_video1;
    TextView name;
    TextView coursePrice;
    TextView instructorName;
    TextView rating;
    TextView totalNumberOfRating;
    RatingBar starRating;
    TextView tvweekly_class,tvweekly_exam,tvreview_class,tvcourse_upload,tvrecord_upload,tvlifetime_access,tvCategory,tvDiscountprice,tvMentor,tvcompare,tvBestseller,tvClass_schedule;
    RelativeLayout monthly_couching;
    LinearLayout layout_classschedule;

    public ViewHolder(View itemView) {
        super(itemView);
        image = itemView.findViewById(R.id.courseThumbnail);
        image1 = itemView.findViewById(R.id.courseThumbnail1);
        name = itemView.findViewById(R.id.courseTitle);
        coursePrice = itemView.findViewById(R.id.tvcoursePrice);
        instructorName = itemView.findViewById(R.id.instructorName);
        rating = itemView.findViewById(R.id.numericRating);
        totalNumberOfRating = itemView.findViewById(R.id.totalNumberOfRatingByUsers);
        starRating = itemView.findViewById(R.id.starRating);
        tvweekly_class=itemView.findViewById(R.id.tvweekly_class);
        tvweekly_exam=itemView.findViewById(R.id.tvweekly_exam);
        tvreview_class=itemView.findViewById(R.id.tvreview_class);
        tvcourse_upload=itemView.findViewById(R.id.tvcourse_upload);
        tvrecord_upload=itemView.findViewById(R.id.tvrecord_upload);
        tvlifetime_access=itemView.findViewById(R.id.tvlifetime_access);
        tvCategory=itemView.findViewById(R.id.tvCategory);
        tvDiscountprice=itemView.findViewById(R.id.tvDiscountprice);
        tvMentor=itemView.findViewById(R.id.tvMentor);
        play_video=itemView.findViewById(R.id.play_video);
        play_video1=itemView.findViewById(R.id.play_video1);
        tvcompare=itemView.findViewById(R.id.tvcompare);
        tvBestseller=itemView.findViewById(R.id.tvBestseller);
        monthly_couching=itemView.findViewById(R.id.monthly_couching);
        tvClass_schedule=itemView.findViewById(R.id.tvClass_schedule);
        layout_classschedule=itemView.findViewById(R.id.layout_classschedule);

    }
}
}

【问题讨论】：

    标签： java android android-recyclerview


    【解决方案1】：

    我终于找到了解决办法。我的 recyclerview 布局有一个nestedscrollview 将 android:nestedScrollingEnabled="false" 添加到我的recyclerview 解决了我的问题。我不知道为什么，但它解决了我的问题

    【讨论】：

      【解决方案2】：

      RecyclerView 重用视图持有者以提高性能。你也可以说它recycles视图持有者——这就是它得名的地方。

      RecyclerView 适配器不会创建比它需要的更多的视图持有者。视图持有者的数量可以大致等于：

      // consider it pseudocode
viewHoldersCount = recyclerView.height / viewHolder.height + 1

      因此它将生成填满屏幕的视图持有者数量 + 1 个在屏幕外绘制的项目（例如在回收器视图的底部），以平滑滚动动画并消除任何故障。

      以下：onCreateViewHolder 仅用于创建视图持有者！ 永远不要将任何数据绑定到来自onCreateViewHolder 的视图持有者。

      如果您的适配器中有 100 个要显示的项目，但设备的屏幕只能显示 10 个，那么您将有 11 个视图持有者在您滚动列表时重复使用。

      onBindViewHolder 会在每次显示项目时调用 - 这是将数据附加到视图持有者的地方。

      public CoursesAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.course_cell2, parent, false);
    return new ViewHolder(view);
}

public void onBindViewHolder(@NonNull final CoursesAdapter.ViewHolder holder, final int position) {
    final Course currentCourse = mCourses.get(position);

    holder.play_video.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           // ...
        }
    }

    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            switchToCourseDetailsActivity(currentCourse);
        }
    });
}

      【讨论】：

      • 使用这个返回 ViewHolder(view);按照预期的方法调用给出错误，所以我使用了这个最终的 ViewHolder holder = new ViewHolder(view);退货持有人；并按照您的建议移动了项目单击方法。在此之后第一次加载第一个项目点击工作，但最后一个项目仍然存在同样的问题。当我再次向上滚动时，第一项也出现同样的问题。我注意到的另一件事是该项目在第一次加载时有一个图像视图，因为第一个项目图像没有显示，在滚动后它显示，但在第二次点击后再次点击可以工作
      • @Mithu，关于错误 - 我错过了关键字 new。这就是错误的原因。答案已更新。
      • @Mithu，你能上传完整的onBindViewHolder 实现吗？
      • 编辑了我的问题并上传了完整的 onBindViewHolder 方法
      • 如果您不修改 itemView 的点击侦听器，我很确定 switchToCourseDetailsActivity 会被调用。在调用switchToCourseDetailsActivity 的行上设置断点并调试您的应用程序以找到问题。
      猜你喜欢
      • 1970-01-01
      • 2011-11-17
      • 2019-03-12
      • 1970-01-01
      • 1970-01-01
      • 1970-01-01
      • 1970-01-01
      • 2017-07-03
      • 1970-01-01
      相关资源
      最近更新 更多
      热门标签
      Java Python linux javascript Mysql C# Docker 算法 前端 SpringBoot Redis Vue spring 设计模式 .net core .net kubernetes c++ 数据库 数据结构 大数据 js 机器学习 微服务 Android Go 程序员 面试 JVM ASP.net core 云原生 人工智能 后端 PHP git CSS golang k8s Nginx Django mybatis 深度学习 多线程 React 架构 devops 爬虫 云计算 Spring Boot LeetCode