如果我們?cè)诰W(wǎng)上下載的低版本開發(fā)的iOS源代碼，而我們的iOS SDK又是高版本的時(shí)候，就會(huì)有Base SDK Missing的問題纏身，icech在網(wǎng)上搜集了兩個(gè)解決辦法：

方法1：老外的方法，網(wǎng)上流傳廣泛。IPhone Base SDK missing

   1. Load your project
   2. From the menu, select Project > Edit Project Settings...
   3. Under Architecture > Base SDK, choose one of the available device options: iPhone 3.2 or iPhone 4.0. If you are iPhone-only, 4.0 is the way to go.
   4. Close that window.
   5. From the menu, select Project > Edit Active Target "YourTarget"
   6. Under Architecture > Base SDK, choose one of the available device or simulator options: iPhone 3.2 or iPhone 4.0.
   7. If you want to target previous iOS versions, then in that same window, under Deployment > iPhone OS Deployment Target, select the lowest version you want to support. Note that support for 2.x versions through the app store is deprecated. See the "Readiness Checklist" quote above.

方法2：看起來和方法1沒什么區(qū)別，呵呵

解決辦法就是Project->Edit Project Settings->Build標(biāo)簽頁中的將默認(rèn)的Base SDK從3.2版本選擇成現(xiàn)有的iOS SDK 4.2。可這樣依舊不能解決問題。關(guān)鍵還有一個(gè)步驟，Project->Set Active Target，選擇成你現(xiàn)在的工程。盡管你會(huì)看到，Project->Set Active Target中只有你現(xiàn)在工程的名稱，并且已經(jīng)打鉤了，但你仍然要用鼠標(biāo)點(diǎn)擊一下。