如何将编辑文本值从适配器传递到活动？

Question

我有一个回收器视图适配器，它在 edittext 中接受用户的输入。我想将这些值作为列表传递回存在回收器视图的活动。 我需要在活动中将此列表作为参数通过改造发送到 api。

Answer 1

1. 创建一个像这样的接口：

interface IList {
   void addToList(String editTextValue);
}

2. 在您的 Activity 中实现此接口：

class MainActivity extends AppCompatActivity implements IList {

    @Override
    public void addToList(String editTextValue) {
        //TODO("logic for adding to list and sending")
    }
}

3. 添加到 Adapter 的构造函数 Activity，实现 IList 接口，作为参数：

public Adapter(IList listener){
   this.listener = listener;
}

4. 在您的适配器中执行 addToList 方法：

    @Override 
    public void onBindViewHolder(NewViewHolder holder, int position) {
        holder.sendButton.setOnClickListener .setOnClickListener(v -> {
            String newText = holder.editText.text.toString()
            listener.addToList(newText)
        });
    }

Answer 2

有一个工作样本。

MainActivity.java

```    
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.RecyclerView;

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

public class MainActivity extends AppCompatActivity {

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

        Adapter adapter = new Adapter();
        RecyclerView recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setAdapter(adapter);

        EditText editText = findViewById(R.id.editText);
        editText.setOnEditorActionListener((textView, actionId, keyEvent) -> {
            boolean handled = false;
            if (actionId == EditorInfo.IME_ACTION_DONE) {
                // add item
                adapter.addItem(editText.getText().toString());
                // clear text input
                textView.setText("");
                handled = true;
            }
            return handled;
        });
    }
}
    
```

Activity_main.xml

```
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/editText"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:hint="Insert text.."
        android:imeOptions="actionDone"
        android:inputType="text"
        app:layout_constraintBottom_toTopOf="@+id/recyclerView"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0"
        app:layout_constraintVertical_chainStyle="packed" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText" />

</androidx.constraintlayout.widget.ConstraintLayout>

```

Adapter.java

```    
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

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

public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {

    private List<String> items = new ArrayList<>();

    @NonNull
    @Override
    public Adapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View view = inflater.inflate(android.R.layout.test_list_item, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull Adapter.ViewHolder holder, int position) {
        String currentItem = items.get(position);
        holder.textView.setText(currentItem);
    }

    public void addItem(String item) {
        // add at first position - replace with your desired index
        int index = 0;
        this.items.add(index, item);
        notifyItemInserted(index);
    }

    @Override
    public int getItemCount() {
        return items.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        protected TextView textView;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(android.R.id.text1);
        }
    }
}

You can use the "done" key on the keyboard to notify the adapter that an item has been added.
To display the "done" button in the xml it is necessary to use these two instructions in the edittext

    android:imeOptions="actionDone"
    android:inputType="text"