Sent: Thursday, June 18, 2015 4:50 PM

研究一下進入MY OPPORTUNITY的時候，BUSY INDICATOR為什么消失的很晚（似乎是LIST和DETAIL都好了后才消失）

概括地說，Ross描述的busy dialog在LIST和DETAIL的數(shù)據(jù)都回來了才消失的，這個behavior是working as designed的。具體看下面的代碼。

為了更深入理解busy dialog，可以看附件兩個視頻。

我在Opp header ETAG的后臺實現(xiàn)里加了一個10s的延時。

n 第一個video timeout_1500.wmv: 雖然list和detail的數(shù)據(jù)都ready了，但是因為ETAG需要10s才能返回，整個UI被這個ETAG的request造成的busy dialog鎖住了，直到10s后UI才能點擊
n 第二個video是把默認的timeout從1500毫秒改成30秒，即busy dialog不會顯示。從video里看出UI始終是可操作的，盡管后臺的ETAG還沒有回來。
這個busy dialog實際上也是一種保護措施。如果UI上某些操作必須依賴于最新的ETAG，采用這種方式可以讓user同步的ETAG請求返回UI之前就能夠進行操作，會造成state的inconsistency。

Key message we could find in the source code:

after sap.ca.ui.utils.busydialog.requireBusyDialog() is called in application, we can only see the rotating wheel in UI after 1.5 seconds - defined in BUSYDIALOG_TIMEOUT.

the requireBusyDialog and releaseBusyDialog must be called in pair. There is private variable _iRequiredCount maintained inside the implementation. When require function is called, _iRequiredCount++; release for _iRequiredCount–.

it is obsolete. New application should use sap.m.BusyDialog instead.

Take the process to open Opportunity tile as example.

The bindAggregation in S2.controller.js will trigger the Odata request sent to backend:

request url:

And connectionManager is responsible to call requireBusyDialog:

iRequiredCount changed from 0 to 1:

OpportunityAttachment data is requested. ConnectionManager calls another requireBusyDialog, iRequiredCount changed from 1 tp 2:

in detail view, ETAG refresh operations makes iRequiredCount changed from 2 to 3:

At this time, the response of request in step1 has been returned to frontend, ConnectionManager calls releaseBusyDialog:

iRequiredCount changes from 3 to 2:

Since now iRequiredCount still > 0, the busyDialog will not be closed.

the response for request in step2 is returnd, iRequiredCount changes from 2 to 1:

the ETAG request sent in step3 has response now, iRequiredCount changes from 1 to 0:

now busy dialog is closed:

總結(jié)

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