py35-pyobjc: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

[CYY19930327@…]

ApplematoAir:~ Apple$ sudo port install py35-matplotlib
Warning: xcodebuild exists but failed to execute
Warning: Xcode does not appear to be installed; most ports will likely fail to build.
--->  Computing dependencies for py35-matplotlib
--->  Dependencies to be installed: py35-pyobjc-cocoa py35-pyobjc qhull cmake libarchive lzo2
--->  Building py35-pyobjc
Error: org.macports.build for port py35-pyobjc returned: command execution failed
Error: Failed to install py35-pyobjc
Please see the log file for port py35-pyobjc for details:
    /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_python_py-pyobjc/py35-pyobjc/main.log
Error: The following dependencies were not installed: py35-pyobjc-cocoa py35-pyobjc qhull cmake libarchive lzo2
To report a bug, follow the instructions in the guide:
    http://guide.macports.org/#project.tickets
Error: Processing of port py35-matplotlib failed

[CYY19930327@…]

Please help me.

[ryandesign (Ryan Carsten Schmidt)]

The log says:

xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

Please install Xcode and select it with xcode-select.