[Android] 안드로이드 : 액티비티 수명주기

1. 수명주기란?

수명주기 예시1

 

수명주기 예시 2

 

2. 예시 코드

(1) MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        Toast.makeText(this, "onCreate() 호출됨", Toast.LENGTH_LONG).show();

        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });
    }

    // Generate > Override Methods()


    @Override
    protected void onStart() {
        super.onStart();
        Toast.makeText(this, "onStart() 호출됨", Toast.LENGTH_LONG).show();
    }

    @Override
    protected void onStop() {
        super.onStop();
        Toast.makeText(this, "onStop() 호출됨", Toast.LENGTH_LONG).show();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Toast.makeText(this, "onDestroy() 호출됨", Toast.LENGTH_LONG).show();
    }

    @Override
    protected void onPause() {
        super.onPause();
        Toast.makeText(this, "onPause() 호출됨", Toast.LENGTH_LONG).show();

        SharedPreferences pref = getSharedPreferences("pref", Activity.MODE_PRIVATE);
        SharedPreferences.Editor editor = pref.edit();
        editor.putString("name", "소녀시대");
        editor.commit(); // 저장
    }

    @Override
    protected void onResume() {
        super.onResume();
        Toast.makeText(this, "onResume() 호출됨", Toast.LENGTH_LONG).show();

        SharedPreferences pref = getSharedPreferences("pref", Activity.MODE_PRIVATE);
        if (pref != null) {
            String name = pref.getString("name", "");
            Toast.makeText(this, "복구된 이름 : "+name, Toast.LENGTH_LONG).show();
        }
    }
}