Activity

//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"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:weightSum="1"
    android:background="#aaaaaa"
    android:orientation="vertical"
    android:gravity="center"
    tools:context="com.example.i310_54.myapplication01.MainActivity">





        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="push"
            android:background="#ff0d00"
            android:onClick="f1"/>


</LinearLayout>

// MainActivity.java
 
package com.example.i310_54.myapplication01;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.DataSetObserver;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.Spinner;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.LinkedList;
import java.util.List;

public class MainActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        Button button2=findViewById(R.id.button2);

        String na1=Integer.toString(data.getIntExtra("res",0));
        button2.setText(na1+"초");


    }

    public void f1(View view) {


      Intent intent=new Intent(getApplicationContext(),AppleActivity.class);
        Calendar c = Calendar.getInstance();


      int h=c.get(Calendar.HOUR);
      int m=c.get(Calendar.MINUTE);
      int s=c.get(Calendar.SECOND);
      int d=c.get(Calendar.DAY_OF_WEEK);

      Log.v("test",h+" "+m);
      String ar[]=new String[]{"일","월","화","수","목","금","토"};


      intent.putExtra("h",h);
      intent.putExtra("m",m);
      intent.putExtra("s",s);
      intent.putExtra("d",ar[d-1]);

      startActivityForResult(intent,101);


    }


}
// activity_apple.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"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:weightSum="1"
    android:background="#aaaaaa"
    android:orientation="horizontal"
    tools:context="com.example.i310_54.myapplication01.AppleActivity">



        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="previous page"
            android:onClick="f1"
            />


</LinearLayout>
// AppleActivity.java
package com.example.i310_54.myapplication01;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import java.util.Calendar;

public class AppleActivity extends AppCompatActivity {

int h;
int m;
int s;
int d;
String date;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_apple);

        Intent intent=getIntent();
        h=intent.getIntExtra("h",0);
        m=intent.getIntExtra("m",0);
        s=intent.getIntExtra("s",0);
        d=intent.getIntExtra("d",0);
       date=intent.getStringExtra("d");

        Button button3=findViewById(R.id.button3);
        button3.setText(date+"요일"+h +"시 "+m+"분 "+s+"초");





    }

    public void f1(View view){

    Intent intent=new Intent();
        int ah=h*3600;
        int am=m*60;
        int res=ah+am+s;


    intent.putExtra("res",res);


    setResult(1000,intent);
    finish();
    }


}
// AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.i310_54.myapplication01">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="zombie"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".AppleActivity"
            android:label="apple"
            android:theme="@style/AppTheme">

        </activity>
            </application>

</manifest>