3-2-2 부가데이터

MainActivity

package com.example.boostcoursepractice;
 
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.ComponentName;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
 
import com.google.android.material.snackbar.Snackbar;
 
import org.w3c.dom.Text;
 
import java.util.ArrayList;
 
public class MainActivity extends AppCompatActivity {
 
    Button menuBtn ;
    String[] names = {"김준수", "황수연", "차두리"} ;
    static int k =3 ;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        menuBtn = (Button) findViewById(R.id.button);
        menuBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent =new Intent(getApplicationContext(), MenuActivity.class);
 
                ArrayList<String> names = new ArrayList<String>() ;
                names.add("김건모");
                names.add("조정치");
                intent.putExtra("names", names);
 
                SimpleData simpleData = new SimpleData(27,"김미미");
                intent.putExtra("simpleData", simpleData);
 
                startActivityForResult(intent, 101);
            }
        });
    }
 
 
}
 

 

MenuActivity

package com.example.boostcoursepractice;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
 
import java.util.ArrayList;
 
public class MenuActivity extends AppCompatActivity {
 
    Button serialBtn;
    Button parcelBtn;
    Button backBtn;
    Intent intent;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu);
 
        serialBtn = (Button)findViewById(R.id.serial_btn);
        parcelBtn = (Button)findViewById(R.id.parcel_btn) ;
        backBtn = (Button)findViewById(R.id.button2);
        intent = getIntent() ;
 
        serialBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ArrayList<String> names = (ArrayList<String>) intent.getSerializableExtra("names");
 
                String temp = "";
                for(int i=0 ; i<names.size() ; i++)
                {
                    temp += names.get(i) + " " ;
                }
                Toast.makeText(getApplicationContext(), temp, Toast.LENGTH_LONG).show() ;
            }
        });
 
        parcelBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
               SimpleData simpleData = (SimpleData) intent.getParcelableExtra("simpleData");
                Toast.makeText(getApplicationContext(),  simpleData.number + " "+simpleData.message, Toast.LENGTH_LONG).show() ;
            }
        });
 
 
 
        backBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });
 
 
    }
}

 

SimpleData

package com.example.boostcoursepractice;
 
import android.os.Parcel;
import android.os.Parcelable;
 
public class SimpleData implements Parcelable {
 
    int number ;
    String message ;
 
    public SimpleData(int number, String message) {
        this.number = number;
        this.message = message;
    }
 
    public SimpleData(Parcel src)
    {
        number = src.readInt();
        message = src.readString();
    }
 
    public static final Parcelable.Creator CREATOR = new Parcelable.Creator()
    {
        @Override
        public SimpleData createFromParcel(Parcel src) {
            return new SimpleData(src);
    }
 
        @Override
        public SimpleData[] newArray(int i) {
            return new SimpleData[i];
        }
    };
 
    @Override
    public int describeContents() {
        return 0;
    }
 
    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeInt(number);
        parcel.writeString(message);
    }
}
 

 

 activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
    >
 
<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginStart="158dp"
    android:layout_marginLeft="158dp"
    android:layout_marginTop="329dp"
    android:text="메뉴 화면 띄우기" />
</RelativeLayout>

 

acitivity_menu.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=".MenuActivity">
 
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="돌아가기"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.736" />
 
    <Button
        android:id="@+id/serial_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginBottom="52dp"
        android:text="시리얼라이즈로 받은 데이터"
        app:layout_constraintBottom_toTopOf="@+id/parcel_btn"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
 
    <Button
        android:id="@+id/parcel_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="68dp"
        android:text="파슨으로 받은 데이터"
        app:layout_constraintBottom_toTopOf="@+id/button2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

 

액티비티 간의 데이터를 전달할 때 일반전인 데이터가 아닌 객체를 전달할 때는 serialize 방법과 parcel방법 두가지가 있다.

 

ArrayList<String> names = (ArrayList<String>) intent.getSerializableExtra("names");

SimpleData simpleData = (SimpleData) intent.getParcelableExtra("simpleData");

 

이 두가지 메서드를 통해서 받을 수 있다. 일반적으로 시리얼 보단 파슨을 쓰는 것이 권장된다. 파슨을 쓸때는 SimpleData처럼 Parcelable 인터페이스를 implement해 구현하여 사용한다.

 

***Serializable방식을 사용할 때 ArrayList<Object>의 Object가 사용자가 정의한 클래스 일때 implements Serializable로

직렬화해야만 사용할 수 있다.

** 액티비티 간의 데이터를 전달 할 때 공유 되지는 않는다. 아예 새로 만들어져서 전달해주기 때문에 복사하는 형식이다. **

 

 

 

 

시리얼라이즈로 받은 화면

 

 

 

파슨으로 받은화면