[2] Life Cycle, Event

1. Life Cycle

Sameple Source

package com.ssh.user.ex_1201; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; public class LifeActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_life); /* 로그 안드로이드는 예외의 위치를 확인하거나 경로확인 등을 위해서 로그를 사용한다. */ Log.i("MY", "--onCreate"); } /* 호출순서(life cycle) 시작시 : onCreate -> onStart -> onResume 홈버튼 : onPause -> onStop (백그라운드) 재실행 : onRestart -> onStart -> onResume (백그라운드에서 재실행) 종료시 : onPause -> onStop -> onDestroy onCreate : 처음 실행 했을 경우 한번만 호출. onDestroy : 실제 종료시에 한번만 호출. onRestart : 정지 상태에서 실행했을 경우 호출. onStart -> onResume : 실행시 기본 onPause -> onStop : 종료시 기본(백그라운드) */ @Override protected void onDestroy() { super.onDestroy(); Log.i("MY", "--onDestroy"); } @Override protected void onPause() { super.onPause(); Log.i("MY", "--onPause"); } @Override protected void onRestart() { super.onRestart(); Log.i("MY", "--onRestart"); } @Override protected void onResume() { super.onResume(); Log.i("MY", "--onResume"); } @Override protected void onStart() { super.onStart(); Log.i("MY", "--onStart"); } @Override protected void onStop() { super.onStop(); Log.i("MY", "--onStop"); } }

2. Event

Sample Source

package com.ssh.user.ex_1201; import android.graphics.Color; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.TextView; import android.widget.Toast; public class EventActivity extends AppCompatActivity { Button red, blue, toast; TextView txt; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_event); // Button 검색 red = (Button)findViewById(R.id.btn_red); blue = (Button)findViewById(R.id.btn_blue); toast = (Button)findViewById(R.id.btn_toast); // TextView 검색 txt = (TextView)findViewById(R.id.txt); // Button에 Event 감지자를 등록 red.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // Button 클릭시 호출되는 메서드 // TextView 배경색, 내용 변경 txt.setBackgroundColor( Color.RED ); txt.setText("RED"); } }); blue.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { txt.setBackgroundColor( Color.BLUE ); txt.setText("BLUE"); } }); toast.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // Context 정보에 EventActivity.this 로 넘겨 주어도 되지만, getApplicationContext()로 넘길경우 필요한 정보만 추려서 넘길수 있다. // 보통 EventActivity.this를 사용. Toast의 경우에는 getApplicationContext() 이 좋다. // Toast.makeText( EventActivity.this, "출력할 문자열 !!", Toast.LENGTH_LONG ).show(); Toast.makeText( getApplicationContext(), "출력할 문자열 !!", Toast.LENGTH_LONG ).show(); } }); } }

<?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:id="@+id/activity_event" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.ssh.user.ex_1201.EventActivity" android:orientation="vertical"> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center"> <Button android:id="@+id/btn_red" android:layout_width="wrap_content" android:layout_height="match_parent" android:text="red" android:textSize="20dp" /> <Button android:id="@+id/btn_blue" android:layout_width="wrap_content" android:layout_height="match_parent" android:text="blue" android:textSize="20dp"/> <Button android:id="@+id/btn_toast" android:layout_width="wrap_content" android:layout_height="match_parent" android:text="toast" android:textSize="20dp" /> </LinearLayout> <TextView android:id="@+id/txt" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#000" android:text="test" android:textSize="20dp" android:textColor="#fff" android:gravity="center" /> </LinearLayout>

3. Event2

Sample Source

package com.ssh.user.ex_1201; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class Event2Activity extends AppCompatActivity { Button btn; EditText edtxt; TextView txt; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_event2); btn = (Button)findViewById(R.id.start); edtxt = (EditText)findViewById(R.id.ed_txt); txt = (TextView)findViewById(R.id.txt); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String msg = edtxt.getText().toString(); int i; for(i = 0; i < msg.length()/2; i++) if(msg.charAt(i) != msg.charAt(msg.length()-1-i)) break; if(i == msg.length()/2) txt.setText("TRUE"); else txt.setText("FALSE"); } }); } }

<?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:id="@+id/activity_event2" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.ssh.user.ex_1201.Event2Activity" android:orientation="vertical"> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal"> <EditText android:id="@+id/ed_txt" android:layout_width="wrap_content" android:layout_height="match_parent" android:inputType="number" android:ems="10" android:hint="숫자를 입력하세요!!"/> <Button android:id="@+id/start" android:layout_width="match_parent" android:layout_height="match_parent" android:text="Start"/> </LinearLayout> <TextView android:id="@+id/txt" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#aaa" android:gravity="center" android:text="Result" android:textSize="30dp" /> </LinearLayout>