android - onSuccessTask 与 addOnSuccessListener？

Question

我正在使用 Google Firestore对于 Android 数据库，想知道 onSuccessTask 和 addOnSuccessListener 之间的区别。

例如，这是我更新一个 Firestore 文档:

val doc = db.collection("books").document(book).update(data)

对于上述情况，要在更新完成后采取行动，我可以执行以下任一操作:

.onSuccessTask { } or .addOnSuccessListener { }

对我来说，产生完全相同的结果。

谁能弄清楚区别是什么以及应该使用哪一个？

Answer 1

Task 的 addOnSuccessListener() 共有三种类型方法是:

• addOnSuccessListener(Executor executor, OnSuccessListener listener) :

Adds a listener that is called if the Task completes successfully.

• addOnSuccessListener(OnSuccessListener listener) :

Adds a listener that is called if the Task completes successfully.

• addOnSuccessListener(Activity activity, OnSuccessListener listener) :

Adds an Activity-scoped listener that is called if the Task completes successfully.

还有两种类型的 Task 的 onSuccessTask()方法是:

• onSuccessTask(Executor executor, SuccessContinuation successContinuation) :

Returns a new Task that will be completed with the result of applying the specified SuccessContinuation to this Task when this Task completes successfully.

• onSuccessTask(SuccessContinuation successContinuation) :

Returns a new Task that will be completed with the result of applying the specified SuccessContinuation to this Task when this Task completes successfully.

正如您可能看到的，主要区别在于，在 addOnSuccessListener() 的情况下返回的对象类型为 abstract Task<TResult> ，因此每次使用它时，您都需要在使用 onSuccessTask() 时为其提供一个实现。方法，返回的对象类型是 <TContinuationResult> Task<TContinuationResult> (这不是抽象的)。