[Java] Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK

Intent.FLAG_ACTIVITY_NEW_TASK  or  Intent.FLAG_ACTIVITY_CLEAR_TASK

---

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1 페이지"
        android:textSize="30dp" />

    <Button
        android:id="@+id/btnMain"
        android:layout_width="220dp"
        android:layout_height="80dp"
        android:text="다음 페이지로 이동"
        android:textSize="22dp"
        android:layout_marginTop="100dp"/>

</LinearLayout>

activity_main,xml

 

 

 

 

 

activity_sub.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".SubActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="2 페이지"
        android:textSize="30dp" />

    <Button
        android:id="@+id/btnSub"
        android:layout_width="220dp"
        android:layout_height="80dp"
        android:text="처음으로 이동"
        android:textSize="22dp"
        android:layout_marginTop="100dp"/>

</LinearLayout>

activity_sub.xml

 

 

 

 

 

SubActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;

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

public class SubActivity extends AppCompatActivity {

    private Button btnSub;

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

        btnSub = findViewById(R.id.btnSub);
        btnSub.setOnClickListener(new View.OnClickListener() {

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

        });
    }

}

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {

    private Button btnMain;

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

        btnMain = findViewById(R.id.btnMain);
        btnMain.setOnClickListener(new View.OnClickListener() {

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

        });

    }
}

activity가 스택처럼 쌓인다.

 

실행 결과

 

 

 

 

---

SubActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;

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

public class SubActivity extends AppCompatActivity {

    private Button btnSub;

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

        btnSub = findViewById(R.id.btnSub);
        btnSub.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), MainActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                startActivity(intent);
            }

        });
    }

}

SubActivity.java 에만

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);  추가
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);  추가

 

실행 결과

 

 

 

 

---

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {

    private Button btnMain;

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

        btnMain = findViewById(R.id.btnMain);
        btnMain.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), SubActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                startActivity(intent);
            }

        });

    }
}

MainActivity.java 에도

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);  추가
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);  추가

 

실행 결과