스레드 (Thread) - 2. 핸들러를 이용한 스레드 구현 (1)

1. 구현 결과 화면

    

2. activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
 
    <TextView
        android:id="@+id/text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="현재 값 : "
        android:textSize="25sp"
        android:textStyle="bold"
        android:textAlignment="center"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@id/button"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"/>
 
    <Button
        android:id="@+id/button"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:text="스레드 시작"
        android:textSize="20sp"
        app:layout_constraintTop_toBottomOf="@id/text_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>
 
</android.support.constraint.ConstraintLayout>

3. MainActivity.java

package com.tistory.qlyh8.pracitice;
 
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity  {
 
    TextView textView;
    Button button;
    ValueHandler handler = new ValueHandler();
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        textView = findViewById(R.id.text_view);
 
        button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                BackgroundThread thread = new BackgroundThread();
                thread.start(); // run() 메서드 호출
            }
        });
    }
 
    // 1초마다 값이 1씩 증가하는 스레드
    class BackgroundThread extends Thread {
        boolean isRunning = false;
        int value = 0;
 
        @Override
        public void run() {
            isRunning = true;
            while(isRunning){
                value += 1;
 
                Message msg = handler.obtainMessage(); // 메시지 객체를 참조
 
                Bundle bundle = new Bundle();
                bundle.putInt("value", value);
                msg.setData(bundle);
                handler.sendMessage(msg);   // 핸들러로 메시지를 보낸다.
 
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
 
    class ValueHandler extends Handler {
        @Override
        public void handleMessage(Message msg) { // 메시지 객체 처리
            super.handleMessage(msg);
            Bundle bundle = msg.getData();
            textView.setText("현재 값 : "+  bundle.getInt("value"));
        }
    }
}

 

출처: https://www.edwith.org/boostcourse-android/lecture/17086