Contact App : AlertDialog, RecyclerView, Adapter...

app / res / layout / 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"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <EditText
                android:id="@+id/editName"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginStart="16dp"
                android:ems="10"
                android:inputType="text"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <EditText
                android:id="@+id/editPhone"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginStart="16dp"
                android:ems="10"
                android:inputType="number"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/editName" />

            <Button
                android:id="@+id/btnSave"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:layout_marginEnd="16dp"
                android:text="저장"
                android:textSize="24sp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="parent" />
        </androidx.constraintlayout.widget.ConstraintLayout>

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

 

 

 

app / res / layout / contact_row.xml

 

 

 

 

app / java / com.bpdev.simplecontacts / MainActivity.java 

package com.bpdev.simplecontacts;

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

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import com.bpdev.simplecontacts.adapter.ContactAdapter;
import com.bpdev.simplecontacts.model.Contact;
import com.google.android.material.snackbar.Snackbar;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    EditText editName;
    EditText editPhone;
    Button btnSave;

    RecyclerView recyclerView;
    ContactAdapter adapter;
    // 데이터는 메모리에 있어야 해 메모리 안에서 담을 곳이 필요하다.
    ArrayList<Contact> contactList = new ArrayList<>();


    // 셋팅하고 대기하다가 온클릭 들어오면 저장하고 , 출력한다....
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 연결
        editName = findViewById(R.id.editName);
        editPhone = findViewById(R.id.editPhone);
        btnSave = findViewById(R.id.btnSave);

        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));

        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String name = editName.getText().toString().trim();
                String phone = editPhone.getText().toString().trim();

                if (name.isEmpty() || phone.isEmpty()) {
                    Snackbar.make(btnSave, "필수항목을 모두 입력하세요.", Snackbar.LENGTH_SHORT).show();
                    return;
                }
                // 묶음이니까 클래스로 만들어서 저장

                Contact contact = new Contact(name, phone); // 이렇게 하자
                contactList.add(0, contact); // ㅊㄱ

                // 화면 표시하는 어댑터한테 알려줘야 한다. 어댑터는 눈이 없다..
                adapter.notifyDataSetChanged();

                // 원래 있던 정보는 클리어하자
                editName.setText("");
                editPhone.setText("");

            }
        });

        adapter = new ContactAdapter(MainActivity.this, contactList); // 나는 여기서 어댑터 만들어
        recyclerView.setAdapter(adapter);
    }
}

 

 

 

 

app / java / com.bpdev.simplecontacts / adapter / ContactAdapter.java 

package com.bpdev.simplecontacts.adapter;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

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

import com.bpdev.simplecontacts.R;
import com.bpdev.simplecontacts.model.Contact;

import java.util.ArrayList;

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

    Context context;
    ArrayList<Contact> contactList;

    public ContactAdapter(Context context, ArrayList<Contact> contactList) {
        this.context = context;
        this.contactList = contactList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Contact contact = contactList.get(position);

        holder.txtName.setText( contact.getName() );
        holder.txtPhone.setText( contact.getPhone() );

    }

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

    public class ViewHolder extends RecyclerView.ViewHolder{

        TextView txtName;
        TextView txtPhone;
        ImageView imgDelete;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            txtName = itemView.findViewById(R.id.txtName);
            txtPhone = itemView.findViewById(R.id.txtPhone);
            imgDelete = itemView.findViewById(R.id.imgDelete);

            imgDelete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Log.i("ContactAdapter", "엑스버튼 눌렀음");
                    showAlertDialog();
                }
            });
        }

        // AlertDialog는 Activity에서만 작동한다.
        private void showAlertDialog() {
            AlertDialog.Builder builder = new AlertDialog.Builder(context);
            builder.setTitle("주소록 삭제");
            builder.setMessage("정말 삭제하시겠습니까?");
            builder.setCancelable(false);
            // Yes 버튼 누르면 동작하라~
            builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    // contactArrayList 안에 있는 인덱스에 해당하는 데이터를 사용하면 된다.
                    // 상속받은 함수 이용: 유저가 누른 인덱스를 가져올 수 있는 함수.
                    int index = getAdapterPosition();
                    // 해당 인덱스의 데이터를 삭제한다.
                    contactList.remove(index);
                    // 어댑터에게 화면갱신하라고 알랴줌
                    notifyDataSetChanged();
                    // 화면은 어댑터에게 맡기면 된다.
                }
            });
            builder.setNegativeButton("NO", null);
            builder.show();
        }
    }
}

 

 

 

 

app / java / com.bpdev.simplecontacts / model / Contact.java 

package com.bpdev.simplecontacts.model;

public class Contact {

    private String name;
    private String phone;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public Contact(String name, String phone) {
        this.name = name;
        this.phone = phone;
    }
}