我在RecyclerView中添加資料，但資料沒有立即反映-有解無憂

我正在嘗試添加資料，Recycler View但我從中提取的資料Edit Text沒有立即插入。只有在我執行一些其他操作（例如洗掉串列）之后才會插入資料。我在這里附上了我所有的代碼。

我認為notifyDataSetChanged當我嘗試從編輯文本中添加新文本時不會被呼叫。

代碼：

MainActivity.java

package com.example.sqlitedatabase;

import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;
import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

Adapter adapter;
RecyclerView recyclerView;
TextView textView;
ImageView addTodo;
ConstraintLayout constraintLayout;
ConstraintLayout editTextContainer;


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

    ArrayList<ListModel> list = new ArrayList<>();
    editTextContainer = findViewById(R.id.constraintParentOfAddTodo);
    textView = findViewById(R.id.textView);
    addTodo = findViewById(R.id.addTodo);
    addData(list);

    addTodo_onClickListener(list);

    adapter = new Adapter(this);
    recyclerView = findViewById(R.id.recyclerView);
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    adapter.setList(list);


}

private void addTodo_onClickListener(ArrayList<ListModel> list) {
    addTodo.setOnClickListener(v -> {
        addTodo.setVisibility(View.GONE);
        
        View view = getLayoutInflater().inflate(R.layout.after_add_clicked, null, false);
        //Used for USERS input
        EditText editText = (EditText) view.findViewById(R.id.editTextTodo);
        //This ImageView is used as a button to set data in list
        ImageView setTodo = (ImageView) view.findViewById(R.id.sendTodo);
        Animation animAddTodo = AnimationUtils.loadAnimation(MainActivity.this, R.anim.righttoleft);
        view.setAnimation(animAddTodo);
        editTextContainer.addView(view);

        setTodo_onClickListener(editText, setTodo, list, view);

    });

}

private void setTodo_onClickListener(EditText editText, ImageView setTodo, ArrayList<ListModel> list, View view) {
    setTodo.setOnClickListener(v -> {
                String txt = editText.getText().toString();
                addToList(list, txt);
                view.setVisibility(View.GONE);
                addTodo.setVisibility(View.VISIBLE);
            }
    );
}

//this function is Supposed to add new data to To do list
private void addToList(ArrayList<ListModel> list, String text) {
    //no work is done on id
    list.add(new ListModel(1, text, true));
}

//for displaying list initially
//this data gets inserted instantly
//No problem with them.
private void addData(ArrayList<ListModel> list) {
    list.add(new ListModel(1, "1", false));
    list.add(new ListModel(2, "2", false));
    list.add(new ListModel(3, "3", false));
    list.add(new ListModel(4, "4", false));
    list.add(new ListModel(5, "5", false));
    list.add(new ListModel(6, "6", false));
    list.add(new ListModel(7, "7", false));
    list.add(new ListModel(8, "8", false));
    list.add(new ListModel(9, "9", false));
    list.add(new ListModel(10, "10", false));

}

配接器.java

package com.example.sqlitedatabase;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

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

import java.util.ArrayList;

public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
private final Context context;
private ArrayList<ListModel> list = new ArrayList<>();

public Adapter(Context context) {
    this.context = context;
}

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

@Override
public void onBindViewHolder(@NonNull Adapter.ViewHolder holder, int position) {
    holder.todoText.setText(list.get(position).getText());

    holder.notDoneBtn.setOnClickListener(v -> {
                if (list.size() != 0) {

                    list.remove(list.get(position));
                    notifyDataSetChanged();

                }
            }
    );

}

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

public void setList(ArrayList<ListModel> list) {
    this.list = list;
    notifyDataSetChanged();
}

public static class ViewHolder extends RecyclerView.ViewHolder {

    private final TextView todoText;
    private final ImageView doneBtn;
    private final ImageView notDoneBtn;
    private  final RelativeLayout listBlock;

    public ViewHolder(@NonNull View itemView) {
        super(itemView);
        listBlock=itemView.findViewById(R.id.listBlock);
        todoText = itemView.findViewById(R.id.todoText);
        doneBtn = itemView.findViewById(R.id.doneBtn);
        notDoneBtn = itemView.findViewById(R.id.notDoneBtn);

    }
}

}

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:id="@ id/constraintLayout"
    android:layout_width="match_parent"
    android:background="@color/white"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@ id/textView"
        android:layout_width="200dp"
        android:layout_height="120dp"
        android:layout_marginTop="4dp"
        android:fontFamily="sans-serif-condensed"
        android:gravity="center"
        android:text="TO-DO LIST"
        android:textSize="28sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.502"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </TextView>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@ id/constraintLayout3"
        android:layout_width="300dp"
        android:layout_height="480dp"
        android:layout_marginTop="12dp"

        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@ id/textView"
        app:layout_constraintVertical_bias="0.0">

        <ScrollView
            android:layout_width="300dp"
            android:layout_height="match_parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="1.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.50">

            <androidx.recyclerview.widget.RecyclerView
                android:id="@ id/recyclerView"
                android:layout_width="280dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:layout_marginTop="12dp">

            </androidx.recyclerview.widget.RecyclerView>

        </ScrollView>
    </androidx.constraintlayout.widget.ConstraintLayout>


    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@ id/constraintParentOfAddTodo"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_marginBottom="2dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@ id/constraintLayout3"
        app:layout_constraintVertical_bias="0.794">

        <ImageView
            android:id="@ id/addTodo"
            android:layout_width="44dp"
            android:layout_height="44dp"
            android:layout_marginVertical="0dp"
            android:backgroundTint="@color/white"
            android:elevation="10dp"
            android:src="@drawable/add_circle_48px"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.956"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

        </ImageView>
    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

list_template.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:layout_height="42dp"
    android:id="@ id/listBlock"
    android:layout_width="280dp"
    android:layout_gravity="center_horizontal">
    <androidx.cardview.widget.CardView

        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="2dp"
        android:layout_marginStart="1dp"
        android:elevation="200dp"
        app:cardBackgroundColor="#932"
        app:cardCornerRadius="5dp">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@ id/todoText"
                android:layout_width="190dp"
                android:layout_height="40dp"
                android:layout_marginStart="10dp"
                android:fontFamily="monospace"
                android:gravity="center_vertical"
                android:maxHeight="40dp"
                android:padding="5dp"
                android:text="Reading books"
                android:textColor="#EFEBE9"
                android:textSize="14sp"
                android:textStyle="bold">

            </TextView>

            <ImageView
                android:id="@ id/notDoneBtn"
                android:layout_width="32dp"
                android:layout_height="32dp"
                android:layout_alignBottom="@id/todoText"
                android:padding="5dp"
                android:layout_marginStart="5dp"
                android:layout_marginTop="4dp"
                android:layout_marginBottom="4dp"
                android:layout_toEndOf="@ id/todoText"
                android:background="#999999"
                android:src="@drawable/close_20px">
            </ImageView>

            <ImageView
                android:id="@ id/doneBtn"
                android:layout_width="32dp"
                android:layout_height="32dp"
                android:layout_marginStart="4dp"
                android:layout_marginTop="5dp"
                android:layout_marginBottom="4dp"
                android:layout_toEndOf="@ id/notDoneBtn"
                android:background="#999999"
                android:padding="5dp"
                android:src="@drawable/done_20px">

            </ImageView>
        </RelativeLayout>


    </androidx.cardview.widget.CardView>

</RelativeLayout>

after_add_clicked.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">

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="40dp"

    android:layout_marginBottom="2dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="1.0"
    app:layout_constraintStart_toStartOf="parent">


    <com.google.android.material.card.MaterialCardView
        android:id="@ id/materialCardView"
        android:layout_width="310dp"
        android:layout_height="match_parent"
        android:layout_marginStart="50dp"
        android:background="#121212"
        android:backgroundTint="@color/white"
        app:cardCornerRadius="30dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:strokeColor="#888"
        app:strokeWidth="2dp">

        <EditText
            android:id="@ id/editTextTodo"
            android:layout_width="300dp"
            android:layout_height="40dp"
            android:layout_gravity="center"
            android:background="@color/white"
            android:fontFamily="monospace"
            android:gravity="center_vertical"
            android:text="What to do"
            android:inputType="text"
            android:textSize="20sp">

        </EditText>

    </com.google.android.material.card.MaterialCardView>

    <ImageView
        android:id="@ id/sendTodo"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_margin="4dp"
        android:layout_marginStart="4dp"
        android:layout_marginTop="4dp"
        android:layout_marginEnd="4dp"
        android:layout_marginBottom="4dp"
        android:src="@drawable/ic_baseline_send_24"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.529"
        app:layout_constraintStart_toEndOf="@ id/materialCardView"
        app:layout_constraintTop_toTopOf="parent">

    </ImageView>

    <ImageView
        android:id="@ id/cancel"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_margin="4dp"
        android:layout_marginStart="4dp"
        android:layout_marginTop="4dp"
        android:layout_marginEnd="4dp"
        android:layout_marginBottom="4dp"
        android:src="@drawable/close_20px"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@ id/materialCardView"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </ImageView>


</androidx.constraintlayout.widget.ConstraintLayout>


</androidx.constraintlayout.widget.ConstraintLayout>

我在 RecyclerView 中添加資料，但資料沒有立即反映這就是我的應用程式的外觀。

uj5u.com熱心網友回復：

如果您呼叫addToList添加資料，只需將新專案插入到您的 Activity 和 Adapter 共享的串列中 - 配接器不知道有任何更改，因此它不會更新顯示

您應該setList在配接器上呼叫您的函式 - 用新串列替換當前串列（如果它實際上是同一個串列無關緊要），然后呼叫notifyDataSetChanged()以顯示“新”串列。

在您的配接器上擁有這樣的功能總是更好 - 當您有新資料時，您只需將其傳遞給配接器，它可以在內部處理更新自身的細節。傳遞資料的東西不需要知道任何關于它的資訊。如果您想稍后更新配接器的作業方式（比如更具體地更新某些專案，或者使用 a DiffUtil），那么這仍然是一個內部細節 - 傳遞資料的東西只需要像往常一樣傳遞資料.

（您應該setList復制傳入的串列，例如list.toList()- 如果有東西修改了原始串列，您不希望配接器的內部串列發生更改，這可能會導致錯誤。這里很好，但如果您使用DiffUtil例如，您的也oldList將是您的newList，沒有差異意味著沒有更新）

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