要使用要查找的文档ID，首先需要将其存储在变量中.当您将文档添加到数据库中并且使用对 document()方法的调用而没有传递参数时，将生成唯一的ID.要获取该ID，您应该使用以下代码:

In order to use the document id that you are looking for, first you need to store it in a variable. When you are adding a document to the database and you are using a call to document() method without passing an argument, a unique id is generated. To get that id, you should use the following code:

String documentId = postsRef.document().getId();
yourRef.document(documentId).set(yourModelObject);

其中 postsRef 是 Posts 集合的 CollectionReference 对象，而 yourModelObject 是 Post 类.我还建议您将该ID存储为Post文档的属性.

In which postsRef is the CollectionReference object of your Posts collection and yourModelObject is the object of your Post class. I also recommend you store that id, as a property of your Post document.

一旦有了这个ID，就可以像这样使用:

Once you have this id, you can use in your refence like this:

firebaseFirestore
    .collection("Posts")
    .document(documentId)
    .delete().addOnSuccessListener(/* ... */);