問題描述

據我所知，有兩種方法可以從 Activity 中顯示 Dialog.

As far as I can tell, there are two ways to show a Dialog from an Activity.

1. 創建 Dialog(例如，使用 AlertDialog.Builder)，然后調用新創建的 Dialog 的 show() 方法.
2. 調用 Activity 的 showDialog() 方法，傳入一個 int，它唯一地定義了您想要構建的 Dialog 類型.然后重寫 onCreateDialog() 以實際構建 Dialog，Android 將為您顯示它.

1. Create the Dialog (for example, using an AlertDialog.Builder), and then call the newly created Dialog's show() method.
2. Call the Activity's showDialog() method, passing in an int that uniquely defines what sort of Dialog you want to build. Then override onCreateDialog() to actually build the Dialog, and Android will display it for you.

第二種方法似乎是標準做法，但我很好奇我使用哪種方法是否重要.以下是我能想到的:

The second method seems to be the standard practice but I'm curious if there is any reason it matters which one I use. Here's all I can come up with:

使用Dialog.show

1. 如果您需要以某種方式參數化 Dialog，使用 Activity.showDialog 可能會有點尷尬，如 這個問題.您可能必須在成員變量中存儲字符串或其他內容，以便稍后在 onCreateDialog 或 onPrepareDialog 期間檢索它.
2. 創建和修改對話框的邏輯分布在多個地方，可能會使代碼更難閱讀和維護:
   • 你調用showDialog()
   的地方
   • 在被覆蓋的 onCreateDialog 方法中可能很大的 switch 語句中
   • 在被覆蓋的 onPrepareDialog 方法中可能很大的 switch 語句中

1. If you need to parameterize the Dialog in some way, it can be a little awkward to use Activity.showDialog, as described in this question. You may have to store a String or something in a member variable, just so that it can be retrieved moments later during onCreateDialog or onPrepareDialog.
2. The logic for creating and modifying the dialog is spread out across a number of places, potentially making the code harder to read and maintain:
   • The place where you call showDialog()
   • Inside a potentially large switch statement in the overridden onCreateDialog method
   • Inside a potentially large switch statement in the overridden onPrepareDialog method

使用Activity.showDialog的原因:

1. Activity.showDialog 的 API 文檔說 Dialog 是由 Activity 管理"的，我想這會帶來一些好處嗎?但如果你使用 AlertDialog.Builder 也是如此，我認為，因為你將 this 作為參數傳遞給 Builder 的構造函數.
2. 如果您的 Activity 將多次顯示相同(或非常相似)的 Dialog，則此選項只創建一次，而不是每次都創建一個新的，從而減少系統分配空間的壓力用于新對象、垃圾回收等.

1. The API docs for Activity.showDialog say that the Dialog is "managed" by the Activity which I suppose provides some benefit? But this is also true if you use the AlertDialog.Builder, I would think, because you pass in this as an argument to the Builder's constructor.
2. If your Activity is going to show the same (or a very similar) Dialog several times, this option creates it only once, instead of creating a new one each time, thus putting less strain on the system as far as allocating space for new objects, garbage collection, etc.

所以我的問題是，決定何時使用Activity.showDialog和何時使用Dialog.show的標準是什么，為什么?

So my question is, what are the criteria for deciding when to use Activity.showDialog and when to use Dialog.show, and why?

推薦答案

在我看來你應該更喜歡 showDialog 因為這個方法會為你完成大部分工作.例如，您不必擔心更改屏幕方向后會丟失對對話框的引用.它將自動重新創建.Dialog.show 更容易出錯.

In my opinion you should prefer showDialog because this method will do most of the work for you. In example You don't have to worry that you will lose reference to your dialog after changing screen orientation. It will be recreated automatically. Dialog.show is much more prone to errors.

所以我建議你盡可能使用 showDialog.

So I suggest you to use showDialog everywhere you can.

這篇關于Dialog.show() 與 Activity.showDialog()的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！