I began to use QT for it supports both Android and iOS. Before I update the Xcode6.4 to Xcode7.0, everything works pretty fine.
But after the upgrade from 6.4 to 7, those projects I've been working just failed again and again with Xcode7.（I was using Xcode7.0 and QT5.4. I've already update them into Xcode7.1 and QT5.5.1, and the method I describe now still works. ）
但后来我从Xcode6.4升级到了Xcode7，用QT写的项目就总不能编译成功了。（当时我用的还是Xcode7.0和QT5.4. 现在我已经升级到了Xcode7.1和QT5.5.1， 但本文的方法依然可用。）
Then I did some search on StackOverflow and github. It turns out that the problem is because the latest version QT is a little bit slow on supporting the latest Xcode. So I downgraded to Xcode6.4 and found everything OK again.
But as a geek, I always want those kind of tools act as I wish. I do want QT and Xcode7 the same time. Then I find out a way to make it possible, which is what I am writing about now.
To use QT for iPhone, I see that Xcode6.4 is needed definitely. So I try to make a balance by keeping both Xcode6.4 and Xcode7. I install Xcode7 as /Application/Xcode and Xcode6 as /Application/Xcode.
Then it is the time for some trick.I cloned those settings of Kits, Compiler, and Debugger in the QT with changing the link of Xcode.app to Xcode6.app mannully.It works!
So I can be sure that the compatibility problem of QT and Xcode7 is caused by the versions, and we can solve it by rebuilding the toolchain linked to Xcode6.4.
The devices I use for tests include a macbook pro, a iphone 5c, and a redmi 2. The software I used is QT5.5.1 with Xcode6.4 and Xcode7.1.
The tricks is shown as the pictures below.If you still donot know how to do or it doesn't work, please leave a comment about the details here.
Figure 1 Rename The Xcode6.4 to Xcode6 and Xcode7.1 as Xcode.
Figure 2 Add the Kit in QT preference and change the link to Xcode6 as you already renamed under the /Application.
Figure 3 Add the Compiler with the link to Xcode6
Figure 4 Add the Debugger with the link to Xcode6
Figure 5 Add the Kit in your project.
Figure 6 It Works!