[android] actionbar menu ,뒤로가기 버튼 생성

메인 엑티비티에서 쓸 xml를 생성해준다.

<?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/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".model.AddActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="30dp"
        android:layout_marginTop="88dp"
        android:layout_marginEnd="30dp"
        android:text="연락처 추가"
        android:textSize="25sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.497"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="40dp"
        android:layout_marginTop="75dp"
        android:layout_marginEnd="40dp"
        android:ems="10"
        android:hint="이름 입력"
        android:inputType="text"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <EditText
        android:id="@+id/editAge"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="40dp"
        android:layout_marginTop="14dp"
        android:layout_marginEnd="40dp"
        android:ems="10"
        android:hint="전화번호 입력"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editName" />

    <Button
        android:id="@+id/btnSave"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="40dp"
        android:layout_marginTop="115dp"
        android:layout_marginEnd="40dp"
        android:text="저장"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editAge" />

    <EditText
        android:id="@+id/editSalary"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="40dp"
        android:layout_marginTop="14dp"
        android:layout_marginEnd="40dp"
        android:hint="연봉 입력"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editAge" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

 

mainactivity

// 액션바의 메뉴를 화면에 보여주는 함수.
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main,menu);
    return true;
}
// 액션바의 메뉴를 클릭하면 동작하는 함수.
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
    if (item.getItemId()==R.id.menuAdd){
        Intent intent = new Intent(MainActivity.this, AddActivity.class);
        startActivity(intent);
    } // else if(item.getItemId()= R.~~~)

    return super.onOptionsItemSelected(item);
}

 

 

add Activity

 

package com.example.actionbar.model;

import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

import androidx.activity.EdgeToEdge;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

import com.example.actionbar.MainActivity;
import com.example.actionbar.R;

public class AddActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add);
        
        getSupportActionBar().setTitle("포스팅 생성");
        // 엑션바에 화살표를 표시하는 코드
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }
    // 엑션바에서 화살표를 누르면, 이 엑티비티를 종료하도록 한다.


    @Override
    public boolean onSupportNavigateUp() {
        finish();
        return true;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.add,menu);
        return true;
    }
    // 액션바의 메뉴를 클릭하면 동작하는 함수.
    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        if (item.getItemId() == R.id.menuSave) {

        } // else if(item.getItemId()= R.~~~)

        return super.onOptionsItemSelected(item);
    }
}