10-2. 액티비티와 인텐트

* 양방향 인텐트

- startActivityForResult()

- setResult()

 

<MainActivity.java>

package com.example.project10_2;

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

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

public class MainActivity extends AppCompatActivity {

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

        Button btn = (Button)findViewById(R.id.mainBtn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText num1 = (EditText)findViewById(R.id.num1);
                EditText num2 = (EditText)findViewById(R.id.num2);

                Intent intent = new Intent(getApplicationContext(),SecondActivity.class);
                intent.putExtra("Num1", Integer.parseInt(num1.getText().toString()));
                intent.putExtra("Num2", Integer.parseInt(num2.getText().toString()));
                startActivityForResult(intent, 0);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            int hap = data.getIntExtra("Hap", 0);
            Toast.makeText(getApplicationContext(), "합계 : " + hap, Toast.LENGTH_SHORT).show();
        }
    }
}

- startActivityForResult(Intent, param2) : 값을 돌려받기 위해 사용하며 돌려받을 값이 있을 경우 param2>=0으로 설정

- onActivityResult() : setResult()로 값을 돌려주면 오버라이딩한 onActivityResult()가 수행

 

<SecondActivity.java>

package com.example.project10_2;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.annotation.Nullable;

public class SecondActivity extends Activity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
        setTitle("세컨드 액티비티");

        Button btn = (Button)findViewById(R.id.secondBtn);

        Intent intent = getIntent();
        final int hapValue = intent.getIntExtra("Num1", 0) +
                intent.getIntExtra("Num2", 0);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent outIntent = new Intent(getApplicationContext(), MainActivity.class);
                outIntent.putExtra("Hap", hapValue);
                setResult(RESULT_OK, outIntent);
                finish();
            }
        });
    }
}

데이터를 받을 Intent와 데이터를 보내줄 Intent 생성

- setResult(상태코드, Intent) : 메인 엑티비티로 데이터를 돌려준다.

 

* 액티비티 생명주기

: 액티비티의 생성부터 소멸까지의 주기

onCreate() -> onStart() -> onResume() -> MainActivity 실행

if) main activity 종료 : onPause() -> onStop() -> onDestroy()

else if) 다른 액티비티 요청 : onPause() -> onStop() -> 다른 액티비티 실행/종료 -> onRestart() -> onStart() -> onResume()

 

안드로이드 응용 프로그램은 화면이 작기 때문에 동시에 여러 개의 액티비티가 나올 수 없다. 따라서 여러 개의 액티비티로 작성 된 응용 프로그램이 있다면 앞에 나오는 화면 하나만 활성화 상태고 나머지는 모두 비활성화 상태가 된다.

 

+ 로그캣(LogCat)

: 작성 중인 프로그램에 예기치 못한 오류가 발생했을 때 원인을 파악하는 방법 중 하나로 로그캣이라는 화면을 제공해 로그를 확인 할 수 있다.

 

프로젝트1: 로그캣을 이용한 액티비티 생명주기 확인

Button 2개 - 전화걸기(다른 엑티비티), 끝내기(메인 엑티비티 종료)

package com.example.project10_2;

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

import android.app.SearchManager;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onDestroy() {
        super.onDestroy();
        android.util.Log.i("액티비티 테스트", "onDestroy()");
    }

    @Override
    protected void onPause() {
        super.onPause();
        android.util.Log.i("액티비티 테스트", "onPause()");
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        android.util.Log.i("액티비티 테스트", "onRestart()");
    }

    @Override
    protected void onStart() {
        super.onStart();
        android.util.Log.i("액티비티 테스트", "onStart()");
    }

    @Override
    protected void onStop() {
        super.onStop();
        android.util.Log.i("액티비티 테스트", "onStop()");
    }
    
    protected void onResume() {
        super.onResume();
        android.util.Log.i("액티비티 테스트", "onResume()");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("메인 액티비티");
        android.util.Log.i("액티비티 테스트", "onCreate()");

        Button btn1 = (Button)findViewById(R.id.btn1);
        Button btn2 = (Button)findViewById(R.id.btn2);

        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Uri uri = Uri.parse("tel:01012345678");
                Intent intent = new Intent(Intent.ACTION_DIAL, uri);
                startActivity(intent);
            }
        });

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });
    }
}

 

프로젝트2: 액티비티 3개

MainActivity - Button 1개(새 화면 열기)

SecondActivity - Button 2개(새 화면 열기/ 돌아가기)

ThirdActivity - Button 1개(돌아가기)

 

<MainActivity.java>

package com.example.project10_2;

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

import android.app.SearchManager;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

        Button btn = (Button)findViewById(R.id.mainBtn);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
                startActivity(intent);
            }
        });
    }
}

<SecondActivity.java>

package com.example.project10_2;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.annotation.Nullable;

public class SecondActivity extends Activity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
        setTitle("Second 액티비티");

        Button btn1 = (Button)findViewById(R.id.secondBtn1);
        Button btn2 = (Button)findViewById(R.id.secondBtn2);

        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), ThirdActivity.class);
                startActivity(intent);
            }
        });

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });

    }
}

<ThirdActivity.java>

package com.example.project10_2;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.annotation.Nullable;

public class ThirdActivity extends Activity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.third);
        setTitle("Third 액티비티");

        Button btn = (Button)findViewById(R.id.thirdBtn);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });
    }
}

프로젝트3: 명화 선호도 투표 수정2

뷰플리퍼로 인기 순으로 1초마다 자동으로 이미지 나오기

 

<second.xml>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:padding="5dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:layout_margin="5dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="자동보기 시작"
            android:id="@+id/secondBtn1"/>
        <Button
            android:layout_margin="5dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="자동보기 정지"
            android:id="@+id/secondBtn2"/>
    </LinearLayout>

    <ViewFlipper
        android:id="@+id/viewFlipper"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView2"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView3"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView4"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView5"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView6"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView7"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView8"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>

        <ImageView
            android:id="@+id/imageView9"
            android:layout_width="300dp"
            android:layout_height="300dp"
            android:layout_gravity="center"/>
        
    </ViewFlipper>

</LinearLayout>

<SecondActivity.java>

package com.example.project10;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RatingBar;
import android.widget.TextView;
import android.widget.ViewFlipper;

import androidx.annotation.Nullable;

public class SecondActivity extends Activity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
        setTitle("투표 결과");

        final ViewFlipper viewFlipper;
        Integer imageResourceId[] = {R.drawable.image1, R.drawable.image2, R.drawable.image3, R.drawable.image4,
        R.drawable.image5, R.drawable.image6, R.drawable.image7, R.drawable.image8, R.drawable.image9};
        Integer imageId[] = new Integer[]{R.id.imageView1, R.id.imageView2, R.id.imageView3, R.id.imageView4,
        R.id.imageView5, R.id.imageView6, R.id.imageView7, R.id.imageView8, R.id.imageView9};
        ImageView imageView[] = new ImageView[9];
        int[] indexs = {0,1,2,3,4,5,6,7,8};

        Button btn1 = (Button)findViewById(R.id.secondBtn1);
        Button btn2 = (Button)findViewById(R.id.secondBtn2);
        viewFlipper = (ViewFlipper)findViewById(R.id.viewFlipper);
        for(int i=0; i<imageId.length; i++){
            imageView[i] = (ImageView)findViewById(imageId[i]);
        }
        viewFlipper.setFlipInterval(1000);

        Intent intent = getIntent();
        int[] voteCount = intent.getIntArrayExtra("VoteCount");
        String[] imageName = intent.getStringArrayExtra("ImageName");

        for(int i=0; i<voteCount.length-1; i++){
            for(int j= i+1; j<voteCount.length; j++){
                if(voteCount[i] < voteCount[j]){
                    int tmp = voteCount[i];
                    voteCount[i] = voteCount[j];
                    voteCount[j] = tmp;
                    tmp = indexs[i];
                    indexs[i] = indexs[j];
                    indexs[j] = tmp;
                }
            }
        }
        
        for(int i=0; i<indexs.length; i++){
            imageView[i].setImageResource(imageResourceId[indexs[i]]);
        }

        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewFlipper.startFlipping();
            }
        });

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewFlipper.stopFlipping();
            }
        });
    }
}