mac下react-native run-ios报错

求助 ：react-native init Demo 成功了，但虚拟机报错！！！

环境：Mac air 系统10.11.6 (15G1510)

XCode 7.3.1

homebrew

C-Air:~ apple$ brew -v

Homebrew 1.2.1

node

C-Air:~ apple$ node -v

v6.10.3

react－native

C-Air:~ apple$ react-native -v

react-native-cli: 2.0.1

react-native: n/a - not inside a React Native project directory

git

C-Air:~ apple$ git --version

git version 2.7.4 (Apple Git-66)

但是 ：命令 react-native run-ios 出现下面错误 导致XCode的虚拟机起来了，但不能安装app，也不难调试 js 代码

The following build commands failed:

CompileC /Users/apple/Desktop/RN_projects/Demo/ios/build/Build/Intermediates/React.build/Debug-iphonesimulator/React.build/Objects-normal/x86_64/RCTTabBarItem.o Views/RCTTabBarItem.m normal x86_64 objective-c com.apple.compilers.llvm.clang.1_0.compiler

(1 failure)

Installing build/Build/Products/Debug-iphonesimulator/Demo.app

An error was encountered processing the command (domain=NSPOSIXErrorDomain, code=2):

Failed to install the requested application

An application bundle was not found at the provided path.

Provide a valid path to the desired application bundle.

Print: Entry, ":CFBundleIdentifier", Does Not Exist

Command failed: /usr/libexec/PlistBuddy -c Print:CFBundleIdentifier build/Build/Products/Debug-iphonesimulator/Demo.app/Info.plist

Print: Entry, ":CFBundleIdentifier", Does Not Exist

怎么解决这个难题？请教高手 帮 看看 ！！！谢谢了先