如何为每个 recyclerview 项目的按钮添加功能？答案

【问题标题】：How to add functionality to buttons of each of the recyclerview items?如何为每个 recyclerview 项目的按钮添加功能？
【发布时间】：2020-01-15 01:25:12
【问题描述】：

我正在编写一个 android 代码，其中在单击 recyclerview 上的按钮时，它应该将其定向到其他一些活动。该程序应将控件重定向到每个 recyclerview 项目的不同活动。我已经成功地将按钮添加到活动的模板中，但是，我无法理解如何为每个按钮添加功能。我随函附上我在项目中包含的不同文件。如果有人可以指导我如何从这里开始，那将非常有帮助。

ProductPage1.java

package com.agnik.example.myapplication4;

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

import android.os.Bundle;

import java.util.ArrayList;

public class ProductPage1 extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_product_page1);

        ArrayList<ExampleItem> exampleList = new ArrayList<>();
        exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
        exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
        exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));
        exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
        exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
        exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));
        exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
        exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
        exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));
        exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
        exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
        exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));

        mRecyclerView = findViewById(R.id.recyclerView);
        mRecyclerView.setHasFixedSize(true);
        mLayoutManager = new LinearLayoutManager(this);
        mAdapter = new ExampleAdapter(exampleList);

        mRecyclerView.setLayoutManager(mLayoutManager);
        mRecyclerView.setAdapter(mAdapter);

    }
}

ExampleAdapter.java

package com.agnik.example.myapplication4;

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

import java.util.ArrayList;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {

    private ArrayList<ExampleItem> mExampleList;


    public static class ExampleViewHolder extends RecyclerView.ViewHolder
    {
        public ImageView mImageView;
        public TextView mTextView1;
        public TextView mTextView2;
        public Button mButton;

        public ExampleViewHolder(@NonNull View itemView) {
            super(itemView);
            mImageView = itemView.findViewById(R.id.imageView);
            mTextView1 = itemView.findViewById(R.id.textView);
            mTextView2 = itemView.findViewById(R.id.textView2);
            mButton = itemView.findViewById(R.id.mybutton);


        }
    }

    public ExampleAdapter(ArrayList<ExampleItem> exampleList)
    {

        mExampleList = exampleList;

    }

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

        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.example_item, parent, false);
        ExampleViewHolder evh = new ExampleViewHolder(v);
        return evh;

    }

    @Override
    public void onBindViewHolder(@NonNull ExampleViewHolder holder, int position) {

        ExampleItem currentItem = mExampleList.get(position);
        holder.mImageView.setImageResource(currentItem.getImageResource());
        holder.mTextView1.setText(currentItem.getText1());
        holder.mTextView2.setText(currentItem.getText2());

    }

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

    }







}

ExampleItem.java

    package com.agnik.example.myapplication4;

    public class ExampleItem {

        private int mImageResource;
        private String mText1;
        private String mText2;

        public ExampleItem(int imageResource, String text1, String text2) {
            mImageResource = imageResource;
            mText1 = text1;
            mText2 = text2;
        }

        public int getImageResource() {
            return mImageResource;
        }

        public String getText1() {
            return mText1;
        }

        public String getText2() {
            return mText2;
        }

    }

activity_product_page1.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".ProductPage1">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#008080"
        android:padding="4dp"
        android:scrollbars="vertical" />

</RelativeLayout>

example_item.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:cardCornerRadius="4dp">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="4dp">

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:padding="2dp" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_toEndOf="@+id/imageView"
            android:text="Line 1"
            android:textColor="@android:color/black"
            android:textSize="20sp"
            android:textStyle="bold"
            android:layout_toRightOf="@+id/imageView" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/textView"
            android:layout_marginStart="8dp"
            android:layout_toEndOf="@+id/imageView"
            android:text="Line 2"
            android:textSize="15sp"
            android:layout_marginLeft="8dp"
            android:layout_toRightOf="@+id/imageView" />

        <Button
            android:id="@+id/mybutton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/textView2"
            android:layout_marginStart="8dp"
            android:layout_toEndOf="@+id/imageView"
            android:text="Purchase"
            android:textSize="15sp"
            android:layout_marginLeft="8dp"
            android:layout_toRightOf="@+id/imageView"  />


    </RelativeLayout>

</androidx.cardview.widget.CardView>

activity_product_page1.java

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".ProductPage1">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#008080"
        android:padding="4dp"
        android:scrollbars="vertical" />

</RelativeLayout>

enter image description here

编辑：

正如 Phil 所说，我需要将 setOnClickListener 添加到 holder 对象中。但是，当我在 ExampleAdapter.java 上编写代码时，我无法理解如何将控制权从 ProductPage1.class 转移到 SomeOtherActivity.class？

   holder.mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                switch (position) {
                    case 1:                 

                        Intent i = new Intent(ProductPage1.class, PageDemo1_1.class);
                        startActivity(i);
                        break;
                    case 2:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_2.class);
                        startActivity(i);
                        break;
                    case 3:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_3.class);
                        startActivity(i);
                        break;
                    case 4:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_4.class);
                        startActivity(i);
                        break;
                    case 5:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_5.class);
                        startActivity(i);
                        break;
                    case 6:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_6.class);
                        startActivity(i);
                        break;
                    case 7:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_7.class);
                        startActivity(i);
                        break;
                    default:
                        Intent i = new Intent(ProductPage1.class, PageDemo1_3.class);
                        startActivity(i);
                        break;
                }



            }
        });

【问题讨论】：

标签： java android android-studio android-recyclerview android-button

【解决方案1】：

您必须在 ExampleAdapter 的 onBindViewHolder 方法中执行此操作。

例如，您可以这样做：

@Override
public void onBindViewHolder(@NonNull ExampleViewHolder holder, int position) {

    ExampleItem currentItem = mExampleList.get(position);
    holder.mImageView.setImageResource(currentItem.getImageResource());
    holder.mTextView1.setText(currentItem.getText1());
    holder.mTextView2.setText(currentItem.getText2());
    holder.mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // your code here
            }
    });

}

在 onBindViewHolder() 方法中，“逻辑发生了”。在那里，您可以为每个 RecyclerView 项目设置所有内容。

【讨论】：

您能否告诉我如何为每个按钮项添加功能。我无法理解如何访问 recyclerview 中存在的每个按钮。
每个显示的项目都会调用 onBindViewHolder 方法。要检查哪个项目被点击，您可以使用“位置”属性。只需将其设为最终版本，然后您就可以在 onClick() 方法中使用它。也许首先在 onClick() 方法中添加这一行： Log.d("Your Tag", "clicked item with position: " + position);然后你应该看看它是否正常工作。
是的，我明白这一点。我想问的一件事是，由于我在 ExampleAdapter.class 中编写代码，并且应用程序将控件从 Productpage1.java 重定向到 SomeOtherClass.java，所以我应该在 Intent 方法中指定什么名称？
Intent i = new Intent(ProductPage1.class, SomeotherClass.class); startActivity(i);

【解决方案2】：

你需要创建一个类似于普通点击监听器的接口，除了它也有位置作为参数。

public interface RecyclerViewClickListener {
    void onClick(View view, int position);
}

然后你可以在你的适配器中声明

private final RecyclerViewClickListener listener;

你可以在适配器中创建一个设置器

public void setListner(RecyclerViewClickListener listener){
this.listener=listener;
}

【讨论】：

【解决方案3】：

您必须将回调接口添加到适配器中，并将接口的实例从活动传递到适配器构造函数。单击recyclerview项目的不同ViewGroup时调用接口的方法，并且应该在Activity中实现。您的代码将如下所示

活动

    public class ProductPage1 extends AppCompatActivity implements ClickCallback {

        private RecyclerView mRecyclerView;
        private RecyclerView.Adapter mAdapter;
        private RecyclerView.LayoutManager mLayoutManager;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_product_page1);

            ArrayList<ExampleItem> exampleList = new ArrayList<>();
            exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
            exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
            exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));
            exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
            exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
            exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));
            exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
            exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
            exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));
            exampleList.add(new ExampleItem(R.drawable.mickeymouse, "Line1" , "Line2"));
            exampleList.add(new ExampleItem(R.drawable.donalduck, "Line3" , "Line4"));
            exampleList.add(new ExampleItem(R.drawable.popey, "Line5" , "Line6"));

            mRecyclerView = findViewById(R.id.recyclerView);
            mRecyclerView.setHasFixedSize(true);
            mLayoutManager = new LinearLayoutManager(this);
            mAdapter = new ExampleAdapter(exampleList);

            mRecyclerView.setLayoutManager(mLayoutManager);
            mRecyclerView.setAdapter(mAdapter);

        }

       @Override
       onItemClick(int position, View view){
        switch(view.getId()){
           case R.id.mImageView:
         //do your view click events here
            break;
           case R.id.mImageView2:
         //do your view click events here
           break;
         //so on
       }
 }

适配器

public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {

    private ArrayList<ExampleItem> mExampleList;


    public static class ExampleViewHolder extends RecyclerView.ViewHolder
    {
        public ImageView mImageView;
        public TextView mTextView1;
        public TextView mTextView2;
        public Button mButton;

        public ExampleViewHolder(@NonNull View itemView,ClickCallback clickCallback) {
            super(itemView);
this.clickCallback=clickCallback;
            mImageView = itemView.findViewById(R.id.imageView);
            mTextView1 = itemView.findViewById(R.id.textView);
            mTextView2 = itemView.findViewById(R.id.textView2);
            mButton = itemView.findViewById(R.id.mybutton);


        }
    }

    public ExampleAdapter(ArrayList<ExampleItem> exampleList)
    {

        mExampleList = exampleList;

    }

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

        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.example_item, parent, false);
        ExampleViewHolder evh = new ExampleViewHolder(v);
        return evh;

    }

    @Override
    public void onBindViewHolder(@NonNull ExampleViewHolder holder, int position) {

        ExampleItem currentItem = mExampleList.get(position);
        holder.mImageView.setImageResource(currentItem.getImageResource());
        holder.mTextView1.setText(currentItem.getText1());
        holder.mTextView2.setText(currentItem.getText2());

holder.mImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
              clickCallback.onItemClick(position, holder.mImageView);
            //and same for other views
             }

    }

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

    }


    public interface ClickCallback{
        void onItemClick(int position, View view);
         //here you can send the object of the list at the position if you require 
         //that in activity

    }
}

希望你得到答案。快乐编码:)

【讨论】：

【解决方案4】：

此代码在每个单击的项目上显示一个对话框

@NonNull
    @Override
    public ItemViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View view = inflater.inflate(R.layout.recycler_item, null);
        final ItemViewHolder viewHolder = new ItemViewHolder(view);
        dialoge = new Dialog(parent.getContext());
        dialoge.setContentView(R.layout.dialog);
        dialoge.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        viewHolder.container.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                setDialog(dialoge, viewHolder);
                dialoge.show();
            }

        });

        return viewHolder;
    }

在 setDialog() 方法中，您可以使用

获取当前项目位置

final RecyclerItem currentItem = itemList.get(viewHolder.getAdapterPosition());

但我认为最好的做法是考虑使用接口，这里有一个很好的教程可以遵循tutorialRecyclerItemOnClickListenerInterface

希望对你有帮助

编辑：从 onClickListnere 开始一个活动：

Intent myIntent = new Intent(parent.getContext(),yourActivityName.class);
                myIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(myIntent);

【讨论】：