화면 전환(Preference)

 

텍스트를 입력하고
다른 화면으로 이동해서 값을 읽어보도록 하자 

 

 

1. activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">
    <EditText
            android:layout_width="485dp"
            android:layout_height="74dp"
            android:inputType="textPersonName"
            android:ems="10"
            android:id="@+id/editText"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintVertical_bias="0.198"/>
    <Button
            android:text="프리퍼런스 쓰기"
            android:layout_width="485dp"
            android:layout_height="76dp"
            android:id="@+id/write"
            app:layout_constraintTop_toBottomOf="@+id/editText"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintHorizontal_bias="0.504"
            app:layout_constraintVertical_bias="0.077"/>
    <Button
            android:text="다음 화면으로 이동"
            android:layout_width="485dp"
            android:layout_height="76dp"
            android:id="@+id/move"
            app:layout_constraintTop_toBottomOf="@+id/editText"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintHorizontal_bias="0.504"
            app:layout_constraintVertical_bias="0.235"/>

</androidx.constraintlayout.widget.ConstraintLayout>

2. app - src - main - java내 메인패키지 우클릭 - 새로만들기 - Activity - Empty Activity - SecondActivity로 kt파일생성(activity_second 자동생성됨)

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".SecondActivity">

    <TextView
            android:text="TextView"
            android:textSize="30dp"
            android:layout_width="310dp"
            android:layout_height="85dp"
            android:id="@+id/textView"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintVertical_bias="0.179"/>
    <Button
            android:text="프리퍼런스 읽기"
            android:layout_width="310dp"
            android:layout_height="81dp"
            android:id="@+id/read"
            app:layout_constraintTop_toBottomOf="@+id/textView"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            android:layout_marginTop="36dp"/>
</androidx.constraintlayout.widget.ConstraintLayout>

 

 

3. MainActivity.kt

package com.example.sample33

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.EditText

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val write = findViewById<Button>(R.id.write)
        val move = findViewById<Button>(R.id.move)

        val edit = findViewById<EditText>(R.id.editText)

        write.setOnClickListener{
            val pref = getSharedPreferences("pref", MODE_PRIVATE)

            // pref에 대한 공간확보
            val editor = pref.edit()
            // 짐싸기
            editor.putString("mydata", edit.text.toString())
            // 저장
            editor.commit()
            // 초기화
            edit.setText("")
        }
        move.setOnClickListener{
            val i = Intent(this, SecondActivity::class.java)
            startActivity(i)
        }
    }
}

 

4. SecondActivity

class SecondActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_second)

        val read = findViewById<Button>(R.id.read)
        val textView = findViewById<TextView>(R.id.textView)

        read.setOnClickListener{
            val pref = getSharedPreferences("pref", MODE_PRIVATE)

            textView.text = pref.getString("mydata", "")
        }
    }
}

 

AndroidManifest.xml의 드래그한 부분이 있어야 한다.