iPhone通用应用程序。电影播放器​​。框架问题

Question

我有基于3.0 iPhone OS SDK的应用程序 其中一项任务是播放视频（我使用MPMoviePlayerController执行此任务） 现在我尝试使通用应用程序在3.0和3.2操作系统上运行 我完成了apple documentation中描述的所有步骤：升级iPad的当前目标;使用

对符号进行运行时检查

[[UIDevice currentDevice] respondsToSelector:@selector(userInterfaceIdiom)]

功能。但是当我在设备上启动我的应用程序 - 带有OS 3.1.3的iPhone时，我的应用程序崩溃了下一个日志：

Tue May 25 18:00:28 unknown SpringBoard[24] <Notice>: MultitouchHID(208b30) uilock state: 1 -> 0
Tue May 25 18:00:29 unknown SpringBoard[24] <Notice>: MultitouchHID(292580) device bootloaded
Tue May 25 18:00:34 unknown UIKitApplication:...[0xaa0f][1517] <Notice>: dyld: Symbol not found: _MPMoviePlayerWillEnterFullscreenNotification
Tue May 25 18:00:34 unknown UIKitApplication:...[0xaa0f][1517] <Notice>:   Referenced from: /var/mobile/Applications/876EA35E-5756-436B-A9E2-5481D4D62050/....app/...
Tue May 25 18:00:34 unknown UIKitApplication:...[0xaa0f][1517] <Notice>:   Expected in: /System/Library/Frameworks/MediaPlayer.framework/MediaPlayer
Tue May 25 18:00:35 unknown kernel[0] <Debug>: launchd[1517] Builtin profile: container (seatbelt)
Tue May 25 18:00:35 unknown kernel[0] <Debug>: launchd[1517] Container: /private/var/mobile/Applications/876EA35E-5756-436B-A9E2-5481D4D62050 (seatbelt)
Tue May 25 18:00:35 unknown ReportCrash[1518] <Notice>: Formulating crash report for process cnetmobile[1517]
Tue May 25 18:00:36 unknown com.apple.launchd[1] <Warning>: (UIKitApplication:...[0xaa0f]) Job appears to have crashed: Trace/BPT trap
Tue May 25 18:00:36 unknown com.apple.launchd[1] <Warning>: (UIKitApplication:...[0xaa0f]) Throttling respawn: Will start in 2147483646 seconds
Tue May 25 18:00:36 unknown SpringBoard[24] <Warning>: Application '...' exited abnormally with signal 5: Trace/BPT trap
Tue May 25 18:00:36 unknown ReportCrash[1518] <Error>: Saved crashreport to /var/mobile/Library/Logs/CrashReporter/..._2010-05-25-180034_...-iPhone.plist using uid: 0 gid: 0, synthetic_euid: 501 egid: 0
Tue May 25 18:01:36 unknown SpringBoard[24] <Notice>: MultitouchHID(208b30) uilock state: 0 -> 1

正如您所看到的，错误是“未找到符号：_MPMoviePlayerWillEnterFullscreenNotification”。此符号是从iPhone OS 3.2开始在MediaPlayer.framework中提供的通知

那么，我做错了什么？我应该怎样做才能使通用应用程序在OS 3.2（具有新的可用功能）和旧操作系统（具有其功能）上正常工作？

Answer 1

该常量的内容是字符串@"MPMoviePlayerWillEnterFullscreenNotification"，因此您可以使用此字符串代替常量。

或者，你可以

1. 使用functions like dlsym在运行时获取符号;或
2. 使该符号弱链接（=自动执行步骤1）

Answer 2

没有添加MediaPlay.framework。