[Android/Java] Intent

• 화면넘기기
• callback(onActivityResult)

MainActivity.java

package com.example.myapplication;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    //final static String EXTRA_MESSAGE = "com.example.myapplication.MESSAGE";
    public static final int REQUEST_CODE = 1000; // 상수 값을 선언 변하지않는수

    private EditText editText;
    private Button btn_move;
    private int requestCode;
    private int resultCode;
    @Nullable
    private Intent data;

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

        editText = findViewById(R.id.edit_text);
        btn_move = findViewById(R.id.btn_move);

        btn_move.setOnClickListener(this);
        // 1. 익명함수 >> 재사용 안할 때
        /*btn_move.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), IntentActivity.class);

                intent.putExtra("text", editText.getText().toString());

                startActivityForResult(intent, REQUEST_CODE);
            }
        });*/
    }
    // 2. 레이아웃파일에다가 지정하는 방법
    public void sendMessage(View view) {
        Intent intent = new Intent(this, IntentActivity.class);

        intent.putExtra("text", editText.getText().toString());

        startActivityForResult(intent, REQUEST_CODE);
    }
    // 3. 자바파일에서 버튼이랑 온클릭을 연결하는방법
    @Override
    public void onClick(View v) {
        Intent intent = new Intent(this, IntentActivity.class); // 현재 액티비티, 이동하고 싶은 액티비티를 인자로 받음

        intent.putExtra("text", editText.getText().toString()); // 내용을 실어줌

        startActivityForResult(intent, REQUEST_CODE); // 액티비티 이동
    }
    // 뒤로가기
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // 수신 성공!!!
        if(requestCode == REQUEST_CODE && resultCode == RESULT_OK && data != null) {
            //String result = data.getStringExtra("result");
            Toast.makeText(this, "SUCCESS", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "FAIL", Toast.LENGTH_SHORT).show();
        }
    }

}

IntentActivity.java

package com.example.myapplication;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

public class IntentActivity extends AppCompatActivity {

    //private LinearLayout container;
    private TextView textView;
    private Button btn_back;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_intent);
        // 1. 화면에 나타낼 뷰를 지정하는 역할
        // 2. XML 레이아웃 내용을 메모리 상에 객체화하는 역할

        Intent intent = getIntent();
        String text = intent.getStringExtra("text"); // 데이터 수신

        //container = (LinearLayout) findViewById(R.id.activity_intent);
        //LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        //ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.activity_intent, container, false);

        textView = findViewById(R.id.result);
        btn_back =  findViewById(R.id.btn_back);

        textView.setText(text);
        btn_back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.putExtra("comebackhome", btn_back.getText().toString());
                setResult(RESULT_OK, intent); // 결과값 설정
                finish(); // 현재 액태비티 종료 >> 인텐트 액티비티가 파괴됨
            }
        });

    }

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/edit_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="" />

    <Button
        android:id="@+id/btn_move"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="sendMessage"
        android:text="이동" />

</LinearLayout>

activity_intent.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_intent"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".IntentActivity">

    <TextView
        android:id="@+id/result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/btn_back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="뒤로가기" />
</LinearLayout>

 

인텐트로 값을 넘기고 넘긴화면에서 다시 돌아올때 예전 화면에서 result code를 넘기고 예전화면을 파괴하는 코드