Livedata建立observe時，拋Cannot add the same observer with different lifecycles的問題

如果一個activity,在onCreate的時候建立Livedata監聽，當此activity啓動兩遍的時候，會拋出Cannot add the same observer with different lifecycles異常，原因是使用了lamda表達式

public class MyActivity extends AppCompatActivity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     
      liveData.observe(this, value-> {
          ....
      });
    }
    }

使用lamda表達式建立監聽，當Activity未finish的時候，再一次啓動的時候，就會報異常，下面是拋出異常的地方：

public abstract class LiveData<T> {
  @MainThread
    public void observe(@NonNull LifecycleOwner owner, @NonNull Observer<T> observer) {
        if (owner.getLifecycle().getCurrentState() == DESTROYED) {
            // ignore
            return;
        }
        LifecycleBoundObserver wrapper = new LifecycleBoundObserver(owner, observer);
        ObserverWrapper existing = mObservers.putIfAbsent(observer, wrapper);
        /*********************拋出異常的地方***********************/
        if (existing != null && !existing.isAttachedTo(owner)) {
            throw new IllegalArgumentException("Cannot add the same observer"
                    + " with different lifecycles");
        }
        if (existing != null) {
            return;
        }
        owner.getLifecycle().addObserver(wrapper);
    }
   }

原因是在同一個類裏 使用lamda表達式 實例化的對象，竟然是同一個實例，改成原始的new關鍵字就好了

public class MyActivity extends AppCompatActivity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     
      liveData.observe(this,new Observer<String>() {
          @Override
          public void onChanged(@Nullable String s) {

          }
      });
    }
    }