如何使用viewHolder使listView用户输入在屏幕滚动时不返回默认值

Question

I have a listView where a user can enter input to change the textView on each listView row. When you scroll the row off the screen the edited text goes away and the default text reappears. I know this is fixed with the viewHolder but I can't get it to work in my custom adapter class.

MainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.app.Activity;
import android.view.KeyEvent;
import android.view.View;
import android.view.inputmethod.EditorInfo;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ViewSwitcher;

import java.util.ArrayList;

public class MainActivity extends Activity {


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

        final ArrayList<String> Chores = new ArrayList<>();
        //Chores.add("");

        final ListAdapter MyAdapter = new CustomAdapter(this, Chores);
        ListView listViewObject = (ListView)findViewById(R.id.customListView_ID);
        listViewObject.setAdapter(MyAdapter);

        listViewObject.setOnItemClickListener(
            new AdapterView.OnItemClickListener(){
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id){
                    String ChoreString = String.valueOf(parent.getItemAtPosition(position));




                }
            }

        );
        final Button button = (Button) findViewById(R.id.button_ID);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Chores.add("");
                ((ArrayAdapter)MyAdapter).notifyDataSetChanged();

            }

        });




    }
}

CustomAdapter.java

import android.content.Context;
import android.content.DialogInterface;
import android.support.annotation.NonNull;
import android.support.v7.app.AlertDialog;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;

import static com.example.emilythacker.chorelist.R.id.textView_ID;



class CustomAdapter extends ArrayAdapter{

    ArrayList<String> choreText;

    public CustomAdapter(Context context, ArrayList choreText) {
        super(context, R.layout.custon_listview_row, choreText);
        this.choreText = choreText;
    }

    @NonNull
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final ViewHolder holder;

        //final TextView textView = (TextView) customView.findViewById(textView_ID);

        if (convertView == null) {
            LayoutInflater layoutInflater = LayoutInflater.from(getContext());
            convertView = layoutInflater.inflate(R.layout.custon_listview_row, null);
            holder = new ViewHolder();
            holder.imageButton = (ImageButton) convertView.findViewById(R.id.imageButton_ID);
            holder.textView = (TextView) convertView.findViewById(textView_ID);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.textView.setText(choreText.get(position));
        holder.textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //what happens when textView is clicked
                AlertDialog alertDialog = new AlertDialog.Builder(getContext()).create();
                final EditText input = new EditText(getContext());
                input.setHint("hint");
                alertDialog.setView(input);
                alertDialog.setTitle("Set Chore");
                alertDialog.setMessage("Alert message to be shown");
                alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {




                        holder.textView.setText(input.getText().toString());





                        dialog.dismiss();
                    }
                });
                alertDialog.show();

            }
        });



        holder.imageButton.setImageResource(R.drawable.clock);


        return convertView;
    }

    static class ViewHolder {
        ImageButton imageButton;
        TextView textView;
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.emilythacker.chorelist.MainActivity">

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/customListView_ID"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="50dp" />

    <Button
        android:text="Add Chore"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true"
        android:id="@+id/button_ID" />
</RelativeLayout>

custon_listview_row.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"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="60dp">

    <ImageButton
        android:layout_width="60dp"
        android:scaleType="fitCenter"
        app:srcCompat="@drawable/clock"
        android:id="@+id/imageButton_ID"
        android:layout_height="60dp"
        android:background="@null"
        android:layout_alignParentRight="true"
        android:padding="5dp"
        android:layout_weight="1" />


    <TextView
        android:text="Click here to add chore"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:id="@+id/textView_ID"
        android:textSize="25dp"
        android:layout_centerVertical="true"
        android:layout_toStartOf="@+id/imageButton_ID"
        android:layout_marginEnd="11dp"
        />


</RelativeLayout>

Answer 1

When text is entered into the edit text, you need to save it to a variable associated with that position, and in getView you need to set the text of the editText to that position's value. Otherwise you'll just have whatever random value was in there last.

Basically, any value that can change in a row's UI must be saved and written to it in getView.