[Do it 안드로이드] Day 16 - 4

* 이해가 안됨.....쩝

<Main>

package com.oneplus.gubong_kim.service;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    EditText edt;

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

        edt = (EditText) findViewById(R.id.editText);

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String name = edt.getText().toString();

                Intent i = new Intent(getApplicationContext(), MyService.class);
                i.putExtra("command", "show");
                i.putExtra("name", name);
                startActivity(i);
            }
        });

        Intent passedIntent = getIntent();
        processCommand(passedIntent);
    }

    private void processCommand(Intent passedIntent) {
        if (passedIntent != null) {
            String command =  passedIntent.getStringExtra("command");
            String name = passedIntent.getStringExtra("name");

            Toast.makeText(this, "서비스로부터 전달받은 데이터 : " + command + ", " + name, Toast.LENGTH_LONG).show();
        }

    }

    @Override
    protected void onNewIntent(Intent intent) {
        processCommand(intent);
        super.onNewIntent(intent);
    }
}

<MyService>

package com.oneplus.gubong_kim.service;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;

public class MyService extends Service {

    private static final String Tag = "MyService";

    public MyService() {
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(Tag, "onCreate() 호출됨");
    }

    @Override
    //service에서는 intent의 정보를 확인 할 때 onStartCommand를 사용한다.
    //즉 intent 명령어를 처리할 때 사용
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d(Tag, "onStartCommand() 호출됨");

        if (intent == null) {
            return Service.START_STICKY;
        } else {
            processCommand(intent);
        } 
        
        return super.onStartCommand(intent, flags, startId);
    }

    private void processCommand(Intent intent) {
        String command = intent.getStringExtra("command");
        String name = intent.getStringExtra("name");
        Log.d(Tag, "전달받은 데이터 : " + command + ", " + name);

        //화면이 없는 서비스에서 화면이 있는 곳으로 정보 띄우기
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        Intent showIntent = new Intent(getApplicationContext(), MainActivity.class);
        //화면이 없으니 뭔가를 만들어 줘야한다.
        showIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK
                 Intent.FLAG_ACTIVITY_SINGLE_TOP
                Intent.FLAG_ACTIVITY_CLEAR_TOP);
        showIntent.putExtra("command", "show");
        showIntent.putExtra("name", name + " from service");
        startActivity(showIntent);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(Tag, "onDestroy() 호출됨");

    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}