Figure 10- 96 IMMessage.h
There’re lots of class methods, among which “instantMessageWithText:flags:” gets our
attention. Seems it returns an IMMessage object, but what’re the 2 arguments? The 1st may be
an NSString object, what about “flag”? I don’t know if you still remember that earlier in this
section, when we were locating [IMChat sendMessage:IMMessage], we’ve “po”ed an
IMMessage object in LLDB:
(lldb) po $r2
IMMessage[from=(null); msg-subject=(null); account:(null); flags=100005; subject='<<
Message Not Loggable >>' text='<< Message Not Loggable >>' messageID: 0 GUID:'966C2CD6-
3710 - 4D0F-BCEF-BCFEE8E60FE9' date:'437730968.559627' date-delivered:'0.000000' date-
read:'0.000000' date-played:'0.000000' empty: NO finished: YES sent: NO read: NO
delivered: NO audio: NO played: NO from-me: YES emote: NO dd-results: NO dd-scanned: YES
error: (null)]Although the “text” is “not loggable”, the “flag” is 100005. Let’s try it out in Cycript:
cy# [IMMessage instantMessageWithText:@"iOSRE test" flags:100005]- [__NSCFString string]: unrecognized selector sent to instance 0x1468c140
Cycript reminds us that NSString failed to respond to @selector(string). In other words, the
1st argument is not an NSString object, but instead some class that can respond to
@selector(string). Let’s try to get some clues in figure 10-96, do you see “NSAttributedString
*_text” in line 17? According to the official documents, NSAttributedString does have a property
named “string”, whose getter is “- (NSString *)string”, as shown in figure 10-97.