当我点击 recyclerview 中的任何项目时，应用程序崩溃

Question

我正在创建一个回收器视图，并尝试在使用界面单击任何项目时创建一个 toast（我是第一次这样做）。但是当我点击回收站视图中的任何项目时，我的应用程序崩溃了。

这是我的主要 java 文件代码。

package com.example.creatingrecyclerview;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements newsOnCkicked {
    RecyclerView r;
    String arr[]={"1","2","3","4","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        r=findViewById(R.id.rv);
        r.setLayoutManager(new LinearLayoutManager(this));
        CustomAdapter c=new CustomAdapter(arr,this);
        r.setAdapter(c);
    }

    @Override
    public void onClick(View view) {
        
    }

    @Override
    public String onItemClicked(String s) {
        Toast.makeText(this, "Item clicked is "+ s, Toast.LENGTH_SHORT).show();
        return null;
    }
}

这是我的自定义适配器 java 代码。

package com.example.creatingrecyclerview;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.recyclerview.widget.RecyclerView;

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {

    private String[] localDataSet;
    private newsOnCkicked k;

    /**
     * Provide a reference to the type of views that you are using
     * (custom ViewHolder).
     */
    public static class ViewHolder extends RecyclerView.ViewHolder {
        private final TextView textView;

        public ViewHolder(View view) {
            super(view);
            // Define click listener for the ViewHolder's View

            textView = (TextView) view.findViewById(R.id.textView2);
        }

        public TextView getTextView() {
            return textView;
        }
    }

    /**
     * Initialize the dataset of the Adapter.
     *
     * @param dataSet String[] containing the data to populate views to be used
     * by RecyclerView.
     */
    public CustomAdapter(String[] dataSet,newsOnCkicked k) {
        localDataSet = dataSet;
        this.k=k;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
        // Create a new view, which defines the UI of the list item
        View view = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.mylayout, viewGroup, false);
        RecyclerView.ViewHolder v=new ViewHolder(view);
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View vi) {
                k.onItemClicked(localDataSet[v.getAdapterPosition()]);
            }
        });
        return new ViewHolder(view);
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(ViewHolder viewHolder, final int position) {

        // Get element from your dataset at this position and replace the
        // contents of the view with that element
        viewHolder.getTextView().setText(localDataSet[viewHolder.getAdapterPosition()]);
    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return localDataSet.length;
    }
}
interface newsOnCkicked extends View.OnClickListener {
    String onItemClicked(String s);
}

请帮我找出代码中的错误。会很棒:)

Answer 1

您必须使用 viewHolder 设置点击监听器。复制下面的代码然后粘贴运行

     public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {

    private String[] localDataSet;
    private newsOnCkicked k;

    /**
     * Provide a reference to the type of views that you are using
     * (custom ViewHolder).
     */
    public static class ViewHolder extends RecyclerView.ViewHolder {
        private final TextView textView;

        public ViewHolder(View view) {
            super(view);
            // Define click listener for the ViewHolder's View

            textView = (TextView) view.findViewById(R.id.textView2);
        }

        public TextView getTextView() {
            return textView;
        }
    }

    /**
     * Initialize the dataset of the Adapter.
     *
     * @param dataSet String[] containing the data to populate views to be used
     * by RecyclerView.
     */
    public CustomAdapter(String[] dataSet,newsOnCkicked k) {
        localDataSet = dataSet;
        this.k=k;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
        // Create a new view, which defines the UI of the list item
        View view = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.mylayout, viewGroup, false);

        return new ViewHolder(view);
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(ViewHolder viewHolder, final int position) {

        // Get element from your dataset at this position and replace the
        viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View vi) {
                k.onItemClicked(localDataSet[viewHolder.getAdapterPosition()]);
            }
        });
        viewHolder.getTextView().setText(localDataSet[viewHolder.getAdapterPosition()]);
    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return localDataSet.length;
    }
}
interface newsOnCkicked extends View.OnClickListener {
    String onItemClicked(String s);
}

如果仍然收到下面的问题评论和错误日志。

当我点击 recyclerview 中的任何项目时，应用程序崩溃

App is crashing when i click on any item in recyclerview

java

android

android-recyclerview