java - @Nullable java (android) 的含义

Question

我看过这个关于如何在 Android 中创建 fragment 的视频，但我无法理解这里 @Nullable 的含义。 同样在视频 (thenewboston) 中，@Nullable 用于参数:

@Override
public View onCreateView(LayoutInflater inflater,@Nullable ViewGroup container,@Nullable Bundle savedInstanceState)
 {
return super.onCreateView(inflater, container, savedInstanceState);
    }

但后来当我尝试创建相同的覆盖方法时，Android Studio 生成了这个:

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

}

有人可以在这里向我解释一下@Nullable 的用法吗？

Answer 1

表示onCreateView方法的返回值可以为null。

来自Android documentation :

Denotes that a parameter, field or method return value can be null.

When decorating a method call parameter, this denotes that the parameter can legitimately be null and the method will gracefully deal with it. Typically used on optional parameters.

When decorating a method, this denotes the method might legitimately return null.

This is a marker annotation and it has no specific attributes.

您可以在此 Android Support Annotation 中找到更多详细信息和示例页