项目的回收器视图上的空指针异常单击监听器活动在项目被单击时关闭

Question

2020-10-29 16:15:14.953 21026-21026/? E/gamesdownloade: Unknown bits set in runtime_flags: 0x8000
2020-10-29 16:15:14.977 21026-21026/? E/libc: Access denied finding property "persist.sys.theme"
2020-10-29 16:15:15.041 21026-21055/? E/Perf: Fail to get file list com.downloadfrom.psp.gamesdownloader
2020-10-29 16:15:15.042 21026-21055/? E/Perf: getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
2020-10-29 16:15:15.042 21026-21055/? E/Perf: Fail to get file list com.downloadfrom.psp.gamesdownloader
2020-10-29 16:15:15.042 21026-21055/? E/Perf: getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
2020-10-29 16:15:24.376 21026-21026/com.downloadfrom.psp.gamesdownloader E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.downloadfrom.psp.gamesdownloader, PID: 21026
    java.lang.NullPointerException: Attempt to invoke interface method 'void com.downloadfrom.psp.gamesdownloader.ViewHolder$ClickListener.onItemClick(android.view.View, int)' on a null object reference
        at com.downloadfrom.psp.gamesdownloader.ViewHolder$1.onClick(ViewHolder.java:23)
        at android.view.View.performClick(View.java:7259)
        at android.view.View.performClickInternal(View.java:7221)
        at android.view.View.access$3800(View.java:821)
        at android.view.View$PerformClick.run(View.java:27716)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:227)
        at android.app.ActivityThread.main(ActivityThread.java:7842)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)

null

package com.example.my.app;

import android.content.Context;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;

import com.squareup.picasso.Picasso;

public class ViewHolder extends RecyclerView.ViewHolder {

    View view;

    public ViewHolder( View itemView) {
        super(itemView);

        view = itemView;

        itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mClickListener.onItemClick(view,getAdapterPosition());
            }
        });

        itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {

                mClickListener.onItemLongClick(view, getAdapterPosition());

                return true;
            }
        });
    }

    public void setDetails(Context ctx, String title, String image,String download,String size, String discription){

        TextView GameName;
        TextView Size,Download,Discription;
        ImageView GameImage;

        Size = view.findViewById(R.id.Getsize);
        Download = view.findViewById(R.id.Getdownload);
        Discription = view.findViewById(R.id.Getdiscription);

        GameName = view.findViewById(R.id.title_item);
        GameImage = view.findViewById(R.id.thumbnail_item);

        GameName.setText(title);
        Picasso.get().load(image).into(GameImage);
        Size.setText(size);
        Download.setText(download);
        Discription.setText(discription);


    }

    private ViewHolder.ClickListener mClickListener;

    public interface ClickListener{

        void onItemClick(View view,int position);
        void onItemLongClick(View view,int position);
    }

    public void setOnClickListener(ViewHolder.ClickListener clickListener){

        mClickListener = clickListener;

    }

}

这是我在开始方法的主要活动，在这个方法中，我正在从firebase在回收器视图中显示数据，也在单击listener这里设置，请检查

//MainActivity On start Method

@Override
    protected void onStart() {
        super.onStart();
        FirebaseRecyclerAdapter<Games, ViewHolder> firebaseRecyclerAdapter =
                new FirebaseRecyclerAdapter<Games, ViewHolder>(
                        Games.class,
                        R.layout.cardview_list_item,
                        ViewHolder.class,
                        mRef
                ) {
                    @Override
                    protected void populateViewHolder(ViewHolder viewHolder, Games games, int i) {

                        viewHolder.setDetails(getApplicationContext(), games.getTitle(), games.getImage(),
                                games.getSize(),games.getDownload(),games.getDiscription());
                    }

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

                        ViewHolder viewHolder = super.onCreateViewHolder(parent,viewType);

                        viewHolder.setOnClickListener(new ViewHolder.ClickListener() {
                            @Override
                            public void onItemClick(View view, int position) {

                                Toast.makeText(MainActivity.this,"You Clicked on this Game",Toast.LENGTH_SHORT).show();

                            }

                            @Override
                            public void onItemLongClick(View view, int position) {
                                Toast.makeText(MainActivity.this,"You Long Clicked on this Game",Toast.LENGTH_SHORT).show();

                            }
                        });

                        return super.onCreateViewHolder(parent, viewType);
                    }
                };


        recyclerView.setAdapter(firebaseRecyclerAdapter);


    }

并检查模型类

    package com.example.my.app;

public class Games {

    String title;
    String size;
    String image;
    String download;
    String discription;

    public Games() {
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getSize() {
        return size;
    }

    public void setSize(String size) {
        this.size = size;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image = image;
    }

    public String getDownload() {
        return download;
    }

    public void setDownload(String download) {
        this.download = download;
    }

    public String getDiscription() {
        return discription;
    }

    public void setDiscription(String discription) {
        this.discription = discription;
    }
}

Answer 1

ViewHolder viewHolder = super.onCreateViewHolder(parent,viewType);

用这个

View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.your_xml_layout, parent, false);
return new ViewHolder(view);

和@override onbindviewholder方法

@Override
protected void onBindViewHolder(ViewHolder holder, final int position, Model model) {
    holder.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              // your click logic
          }
     });
}

查询此链接