Android RecyclerView嵌套EditView实时更新Item数据

一、场景（例如：购物车）

1、当我们需要以列表样式管理某些数据时，可能需要列表项的某个字段可编辑

2、编辑Item上的某个字段后可能还要更新相关字段的值

二、可能遇到的问题

1、列表滑动导致输入框中的数据错位（或者焦点错位）

2、无法更新Item上相关的字段项的值

3、监听输入框文本更改时陷入死循环

三、可行方案（RecyclerView+TextWatcher）

1、用RecyclerView 实现一个ListView的效果：

package com.zhn.edit.recycler;

import android.os.Bundle;

import android.support.design.widget.FloatingActionButton;

import android.support.design.widget.Snackbar;

import android.support.v7.app.AppCompatActivity;

import android.support.v7.widget.LinearLayoutManager;

import android.support.v7.widget.RecyclerView;

import android.support.v7.widget.Toolbar;

import android.util.Log;

import android.view.View;

import android.view.Menu;

import android.view.MenuItem;

import java.util.ArrayList;

import java.util.List;

public class MainActivity extends AppCompatActivity implements View.OnClickListener,

        EditAbleListAdapter.EditAbleListAdapterListener{

    private FloatingActionButton mFLoatingBtnEmail;

    private RecyclerView mRecyclerEditAble;

    private LinearLayoutManager mEditAbleLayoutManager;

    private EditAbleListAdapter mEditAbleListAdapter;

    private List<datagoods> mDataGoods=new ArrayList<datagoods>();

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        mFLoatingBtnEmail = (FloatingActionButton) findViewById(R.id.floating_btn_email);

        mFLoatingBtnEmail.setOnClickListener(this);

        mRecyclerEditAble= (RecyclerView) findViewById(R.id.recycler_editable);

        initData();

    }

    private void initData() {

        mEditAbleLayoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);

        mRecyclerEditAble.setLayoutManager(mEditAbleLayoutManager);

        mEditAbleListAdapter=new EditAbleListAdapter(this,this);

        mRecyclerEditAble.setAdapter(mEditAbleListAdapter);

        for (int i=;i<;i++){

            mDataGoods.add(new DataGoods("Goods"+i,i,i,i*i));

        }

        mEditAbleListAdapter.refreshDatas(mDataGoods);

    }

    @Override

    public void onClick(View v) {

        switch (v.getId()) {

            case R.id.floating_btn_email:

                for (int i=;i<mdatagoods.size();i++){ 
　　　　　　　　　　　　log.e(mainactivity.class.getsimplename(),mdatagoods.get(i).tostring());="" }="" break;="" default:="" @override="" public="" void="" onedittextchanged(int="" position,="" string="" value)="" {="" todo="" 此处或者回调前应做值合法性验证="" mdatagoods.get(position).setnum(integer.parseint(value));="" <="" pre=""></mdatagoods.size();i++){></datagoods></datagoods>

2、在Adapter中自定义一个Interface 用来将输入的值回传给Activity

3、定义TxtWatcher 接收position和要同步更新的文本框

4、给EditText添加焦点变化的监听器，根据焦点状态绑定和解绑TxtWatcher

package com.zhn.edit.recycler;

import android.content.Context;

import android.support.v7.widget.RecyclerView;

import android.text.Editable;

import android.text.TextWatcher;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.EditText;

import android.widget.TextView;

import java.util.ArrayList;

import java.util.List;

/**

 * Created by zhn

 * 2017/7/9 下午4:20

 */

public class EditAbleListAdapter extends RecyclerView.Adapter{

    public void refreshDatas(List<datagoods> mDataGoods) {

        mDatas.clear();

        mDatas.addAll(mDataGoods);

        notifyDataSetChanged();

    }

    public interface EditAbleListAdapterListener{

        public void onEditTextChanged(int position,String value);

    }

    private Context mContext;

    private List<datagoods> mDatas=new ArrayList<datagoods>();

    private EditAbleListAdapterListener mListener;

    public EditAbleListAdapter(Context context,EditAbleListAdapterListener listener){

        this.mContext=context;

        this.mListener=listener;

    }

    @Override

    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        return new EditAbleListViewHolder(LayoutInflater.from(mContext).inflate(R.layout.item_editable_view,null));

    }

    @Override

    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        ((EditAbleListViewHolder)holder).setContent(position,mDatas.get(position));

    }

    @Override

    public int getItemCount() {

        return mDatas.size();

    }

    public class EditAbleListViewHolder extends RecyclerView.ViewHolder{

        private TextView mTvItemNo;

        private TextView mTvGoodsName;

        private TextView mTvPrice;

        private EditText mEtNum;

        private TextView mTvTotalPrice;

        private TxtWatcher mTxtWatcher;

        public EditAbleListViewHolder(View itemView) {

            super(itemView);

            mTvItemNo= (TextView) itemView.findViewById(R.id.tv_item_no);

            mTvGoodsName= (TextView) itemView.findViewById(R.id.tv_goods_name);

            mTvPrice= (TextView) itemView.findViewById(R.id.tv_price);

            mEtNum= (EditText) itemView.findViewById(R.id.et_num);

            mTvTotalPrice= (TextView) itemView.findViewById(R.id.tv_total_price);

            mTxtWatcher=new TxtWatcher();

        }

        public void setContent(int position,DataGoods data){

            mTvItemNo.setText(String.valueOf(position+));

            mTvGoodsName.setText(data.getGoodsName());

            mTvPrice.setText(String.valueOf(data.getPrice()));

            mEtNum.setText(String.valueOf(data.getNum()));

            mTvTotalPrice.setText(String.valueOf(data.getTotalPrice()));

            mTxtWatcher.buildWatcher(position,mTvTotalPrice);

            mEtNum.setOnFocusChangeListener(new View.OnFocusChangeListener() {

                @Override

                public void onFocusChange(View v, boolean hasFocus) {

                    if(hasFocus){

                        mEtNum.addTextChangedListener(mTxtWatcher);

                    }else{

                        mEtNum.removeTextChangedListener(mTxtWatcher);

                    }

                }

            });

        }

    }

    public class TxtWatcher implements TextWatcher{

        private int mPosition;

        private TextView mTvTotalPrice;

        public void buildWatcher(int position,TextView view){

            this.mPosition=position;

            this.mTvTotalPrice=view;

        }

        @Override

        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override

        public void onTextChanged(CharSequence s, int start, int before, int count) {

            if(s.length()>){

                if(mListener!=null){

                    mListener.onEditTextChanged(mPosition,s.toString());

                    mTvTotalPrice.setText(String.valueOf(mDatas.get(mPosition).getPrice()*Double.parseDouble(s.toString())));

                }

            }else{

                if(mListener!=null){

                    mListener.onEditTextChanged(mPosition,"");

                    mTvTotalPrice.setText("");

                }

            }

        }

        @Override

        public void afterTextChanged(Editable s) {

        }

    }

}

四、选择RecyclerView而不是ListView的原因

RecyclerView 在滑动的时候会使EditText失去焦点，这样可以触发OnFocusChangeListener，这样可以更准确的绑定和解绑TxtWatcher。为什么要解绑TxtWatcher？因为在RecyclerView刷新的时候会重复触发TextWatcher导致很多次无用的回调（甚至死循环）。

ListView在滑动的时候不会使EditText失去焦点，导致了滑动时输入框焦点错位，并且因为输入框是复用的所以导致TextWatcher重复触发很多次（可能是死循环）。

五、注意在布局中设置列表是尽量降低RecyclerView布局重绘的可能性（例如：固定大小等等）

巴特西

Android RecyclerView嵌套EditView实时更新Item数据

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