使用注解代替枚举

原文链接：如何在Android中避免创建不必要的对象

相关的注解为IntDef和StringDef

public class AppConstant {
    public static final int AWAIT = 0;
    public static final int ING = 1;
    public static final int FINISH = 2;

    @IntDef({ AWAIT,ING,FINISH})
    public @interface DoorState{}
}

public class MainActivity extends AppCompatActivity {

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

    private void init(@AppConstant.DoorState int a) {
        System.out.println(a);
    }
}