如何使用数据绑定在ListView中显示输入结果

Question

我正在学习使用数据绑定的自定义数组适配器。 deDittext用于输入“文本”按钮时，输入的文本将显示在listView中。但是，我在EditText中键入的文本不会出现。

mainastivity.java

private Model model = new Model();
private Handlers handlers = new Handlers();
private ViewModel viewModel = new ViewModel(model);
private ArrayList<Model> listItem = new ArrayList<>();
ActivityMainBinding mainBinding = DataBindingUtil.setContentView(this,R.layout.activity_main);


    handlers.setOnClickListener(new MyView.onClickListener() {
        @Override
        public void onDamn(Model model) {
            Model model1 = new Model();
            model1.setText(model1.getText());
            listItem.add(model1);
            viewModel.setAdapter(new CustomAdapter(MainActivity.this, listItem));
            viewModel.getAdapter().notifyDataSetChanged();
        }
    });

    mainBinding.setModel(model);
    mainBinding.setHandlers(handlers);
    mainBinding.setViewModel(viewModel);

<?xml version="1.0" encoding="utf-8"?>
<layout 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">

    <data>
        <variable
            name="model"
            type="com.example.list.Model" />
        <variable
            name="handlers"
            type="com.example.list.Handlers" />
        <variable
            name="viewModel"
            type="com.example.list.ViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="15dp">
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@={model.text}"
            android:layout_marginTop="10dp"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginStart="30dp"
            android:layout_marginEnd="30dp"
            android:hint="hello"/>
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:onClick="@{() -> handlers.onClickListener.onDamn(model)}"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginTop="60dp"
            android:layout_marginStart="45dp"
            android:layout_marginEnd="45dp"
            android:text="damn !"
            android:backgroundTint="@color/black"/>
        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginTop="170dp">
            <ListView
                android:adapter="@{viewModel.adapter}"
                tools:listitem="@layout/activity_item"
                android:layout_width="match_parent"
                android:layout_height="match_parent"/>
        </androidx.constraintlayout.widget.ConstraintLayout>
    </androidx.constraintlayout.widget.ConstraintLayout>



</layout>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <data>
        <variable
            name="viewModel"
            type="com.example.list.ViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{viewModel.modelText}"
            android:textColor="@color/black"
            android:hint="ITEM"
            android:textSize="30sp"
            tools:ignore="MissingConstraints" />
    </androidx.constraintlayout.widget.ConstraintLayout>


</layout>

活动

package com.example.list;

public class Model {
    private String text;

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }
}


*

/strong> *

package com.example.list;

import android.view.View;

import androidx.databinding.BaseObservable;
import androidx.databinding.Bindable;

public class ViewModel extends BaseObservable {
    private Model model;
    public ViewModel(Model model){
        this.model = model;
    }
    public void setModelText(String text){
        model.setText(text);
        notifyPropertyChanged(BR.modelText);
    }
    @Bindable
    public String getModelText(){
        return model.getText();
    }


    private CustomAdapter adapter;

    public void setAdapter(CustomAdapter adapter) {
        this.adapter = adapter;

    }

    public CustomAdapter getAdapter() {
        return adapter;
    }
}

customeadapter

package com.example.list;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.databinding.DataBindingUtil;

import com.example.list.databinding.ActivityItemBinding;

import java.util.ArrayList;
import java.util.List;

public class CustomAdapter extends ArrayAdapter<Model> {
    private Context context;
    private ArrayList<Model> listItem = new ArrayList<>();

    public CustomAdapter(Context context, ArrayList<Model> listItem){
        super(context,0,listItem);
        this.context = context;
        this.listItem = listItem;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        ActivityItemBinding itemBinding = null;
        Model model = listItem.get(position);

        if (convertView == null){
            itemBinding = DataBindingUtil.inflate(LayoutInflater.from(parent.getContext()),R.layout.activity_item,parent,false);
            convertView = itemBinding.getRoot();
        }
        ViewModel viewModel = new ViewModel(model);
        viewModel.setModelText(model.getText());

        itemBinding.setViewModel(viewModel);
        return super.getView(position, convertView, parent);
    }

    @Override
    public int getCount() {
        return listItem.size();
    }

    @Nullable
    @Override
    public Model getItem(int position) {
        return listItem.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    public CustomAdapter(@NonNull Context context, int resource) {
        super(context, resource);
    }

    public CustomAdapter(@NonNull Context context, int resource, int textViewResourceId) {
        super(context, resource, textViewResourceId);
    }

    public CustomAdapter(@NonNull Context context, int resource, @NonNull Model[] objects) {
        super(context, resource, objects);
    }

    public CustomAdapter(@NonNull Context context, int resource, int textViewResourceId, @NonNull Model[] objects) {
        super(context, resource, textViewResourceId, objects);
    }

    public CustomAdapter(@NonNull Context context, int resource, @NonNull List<Model> objects) {
        super(context, resource, objects);
    }

    public CustomAdapter(@NonNull Context context, int resource, int textViewResourceId, @NonNull List<Model> objects) {
        super(context, resource, textViewResourceId, objects);
    }
}