一、場景（例如：購物車）
1、當我們需要以列表樣式管理某些數據時，可能需要列表項的某個字段可編輯
2、編輯Item上的某個字段后可能還要更新相關字段的值
二、可能遇到的問題
1、列表滑動導致輸入框中的數據錯位（或者焦點錯位）
2、無法更新Item上相關的字段項的值
3、監聽輸入框文本更改時陷入死循環
三、可行方案（RecyclerView+TextWatcher）
? ? ? ?1、用RecyclerView 實現一個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>();@Overrideprotected 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=1;i<11;i++){mDataGoods.add(new DataGoods("Goods"+i,i,i,i*i));}mEditAbleListAdapter.refreshDatas(mDataGoods);}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.floating_btn_email:for (int i=0;i<mdatagoods.size();i++){
log.e(mainactivity.class.getsimplename(),mdatagoods.get(i).tostring());="" }="" break;="" default:="" @override="" public="" void="" onedittextchanged(int="" position,="" string="" value)="" {="" todo="" 此處或者回調前應做值合法性驗證="" mdatagoods.get(position).setnum(integer.parseint(value));="" <="" pre=""></mdatagoods.size();i++){></datagoods></datagoods>
? ? ? ?2、在Adapter中自定義一個Interface 用來將輸入的值回傳給Activity
? ? ? ?3、定義TxtWatcher 接收position和要同步更新的文本框
? ? ? ?4、給EditText添加焦點變化的監聽器，根據焦點狀態綁定和解綁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;}@Overridepublic RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {return new EditAbleListViewHolder(LayoutInflater.from(mContext).inflate(R.layout.item_editable_view,null));}@Overridepublic void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {((EditAbleListViewHolder)holder).setContent(position,mDatas.get(position));}@Overridepublic 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+1));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() {@Overridepublic 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;}@Overridepublic void beforeTextChanged(CharSequence s, int start, int count, int after) {}@Overridepublic void onTextChanged(CharSequence s, int start, int before, int count) {if(s.length()>0){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,"0");mTvTotalPrice.setText("0");}}}@Overridepublic void afterTextChanged(Editable s) {}}}
四、選擇RecyclerView而不是ListView的原因
? ? ? ??RecyclerView 在滑動的時候會使EditText失去焦點，這樣可以觸發OnFocusChangeListener，這樣可以更準確的綁定和解綁TxtWatcher。為什么要解綁TxtWatcher？因為在RecyclerView刷新的時候會重復觸發TextWatcher導致很多次無用的回調（甚至死循環）。
? ? ? ? ListView在滑動的時候不會使EditText失去焦點，導致了滑動時輸入框焦點錯位，并且因為輸入框是復用的所以導致TextWatcher重復觸發很多次（可能是死循環）。
五、注意在布局中設置列表是盡量降低RecyclerView布局重繪的可能性（例如：固定大小等等）
 Ubuntu編譯)
