Android Looper차영호 @ganachoco

발표자 소개

Agenda● Java VS Android● Where is main?● Event Loop● Create and Handle Event with Message● Advanced Topic

Android Looper● Event Loop for Android● 공기 같은 존재

○ 어디에나 있지만, 여간해선 사용할 일은 없다.○ 사용할 일은 없지만, 모르면 가끔씩 해결이 곤란할 때가 생긴다.

Java vs Android

Start Entry

public class Hello { public static void main(String[] s) { System.out.println("Hello, World"); }}

public class HelloActivity extends Activity { @Override public void onCreate(Bundle bundle) { super.onCreate(bundle); setContentView(R.layout.activity_hello); }}

Start EntryC:\ > java HelloHello, World

????

간단한 호출경로 확인 방법(Log)

간단한 호출경로 확인 방법(Log)

main()package android.app;

public final class ActivityThread {

public static void main(String[] args) {

// blahblah

Looper.loop();

throw new RuntimeException("Main thread loop unexpectedly exited");

}

}

Event Loopwhile (true) {

// do someting

}

Event Loopwhile (true) {

msg = waitAndGetMessage();

handler = msg.getTarget();

handler.handleMessage(msg);

}

간단한 호출경로 확인 방법(Log)

Message Queue

Image Source: MSDN

Message Queue

Image Source: MSDN

ANR이 반겨줍니다.

Events● Component Lifecycle Event

○ Activity○ Service

● Intent Handler○ BroadcastReceiver.onReceive

● View layout & draw● Input Event

Event Loop● android.os.Message● android.os.Handler● android.os.Looper

○ android.os.HandlerThread

Message@Overridepublic void onClick(View v) { setText("Text 1");}

private static final int MSG_HANDLE_CHANGE_TEXT = 1;

public void setText(String text) { // Message msg = new Message(); // bad usage Message msg = mHandler.obtainMessage(MSG_HANDLE_CHANGE_TEXT, text); mHandler.sendMessage(msg);}

Handlerprivate mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case MSG_HANDLE_TEXT_CHANGED: mTextView.setText((String)(msg.obj)); break; default: break; } }}

Call FlowLooper.loop onClick setText mHandler.sendMessage

... mHandler.handleMessage mTextView.setText

시간

직구를 배웠습니다

변화구도 배워봅시다

Image Source: https://mirror.enha.kr/wiki/야구의 구종

Message Queue

Image Source: MSDN

sendMessageAtFrontOfQueue()

Message Queue

Image Source: MSDNremoveMessages()

Message Queue

Image Source: MSDN

sendMessageDelayed()

sendMessageAtTime()

Requirement

● 안드로이드앱이 시작하고나서 1분 후에 팝업을 띄워주세요.

Solution

Advanced Topic● Wakelock● AlarmManager

Wakelock● View.setKeepScreenOn()● WakeLock

○ FULL_WAKE_LOCK○ SCREEN_BRIGHT_WAKE_LOCK○ SCREEN_DIM_WAKE_LOCK○ PARTIAL_WAKE_LOCK

AlarmManager

● ELAPSED_REALTIME● ELAPSED_REALTIME_WAKEUP● RTC● RTC_WAKEUP

Q&A