macos - 找不到符号 _OBJC_IVAR_$_NSView._layer(在 AppKit 中)仅在 10.7 上，在 10.8 和 10.9 上工作正常

Question

我的 Mac cocoa 应用程序在 10.8 和 10.9 上运行良好，但在 10.7(全新安装)上除外，启动时出现此错误:未找到符号:_OBJC_IVAR__$_NSView._layer

Process:         xxx [875]
Path:            /Users/USER/Desktop/xxx.app/Contents/MacOS/xxx
Identifier:      com.xxx.xxx
Version:         1.0 (1)
Code Type:       X86-64 (Native)
Parent Process:  launchd [127]

Date/Time:       2014-02-13 17:44:24.208 +0100
OS Version:      Mac OS X 10.7.5 (11G63)
Report Version:  9

Crashed Thread:  0

Exception Type:  EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000

Application Specific Information:
dyld: launch, loading dependent libraries

Dyld Error Message:
  Symbol not found: _OBJC_IVAR_$_NSView._layer
  Referenced from: /Users/USER/Desktop/xxx.app/Contents/MacOS/xxx
  Expected in: /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit
 in /Users/USER/Desktop/xxx.app/Contents/MacOS/xxx

(xxx = 应用程序名称)

我检查了系统盘，AppKit框架在/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit目录下没问题

很奇怪，不是吗？感谢您的帮助...

Answer 1

我通过删除所有代码中的以下行解决了该问题:

//self.layer = _layer; //Not necessary at all
self.wantsLayer = YES; //Necessary since 10.8

非常感谢您的帮助!