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List
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=1;i<11;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=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+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() {
@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()>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");
}
}
}
@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)
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