iOS 中有很多 iOS 崩溃报告库，包括 TestFlight和 HockeyApp .如果你不想依赖服务，你仍然可以使用像 PLCrashReporter 这样的库。 .绑定(bind)这些库是 fairly trivial因为他们的公共(public) API 通常由几个具有多种初始化方法的类组成。

但是，当尝试在我们的应用程序中使用 TestFlight 和后来的 HockeyApp 时，我们的应用程序开始随机崩溃。事实证明，这是一个已知问题reported several times ，但 Xamarin 没有对此发出警告，它相对晦涩难懂，我们很难找到它。

我们了解到，所有 iOS 崩溃报告器都会阻止 Mono 捕获空引用异常:

try {
    object o = null;
    o.GetHashCode ();
} catch {
    // Catch block isn't called with crash reporting enabled.
    // Instead, the app will crash.
}

为什么会这样？引用 Xamarin 开发人员 Rolf 的话，

A null reference exception is actually a SIGSEGV signal at first. Usually the mono runtime handles this and translates it into a nullreference exception, allowing the execution to continue. The problem is that SIGSEGV signals are a very bad thing in ObjC apps (and when it occurs outside of managed code), so any crash reporting solution will report it as a crash (and kill the app) - this happens before MonoTouch gets a chance to handle the SIGSEGV, so there is nothing MonoTouch can do about this.

我敢肯定，很多人在 MonoTouch 应用程序中使用 TestFlight，却不知道它会导致崩溃。
Isn't it ironic?

如何让崩溃报告库不使 MonoTouch 应用崩溃？

最佳答案

将其放入 AppDelegate.cs:

[DllImport ("libc")]
private static extern int sigaction (Signal sig, IntPtr act, IntPtr oact);

enum Signal {
    SIGBUS = 10,
    SIGSEGV = 11
}

static void EnableCrashReporting ()
{
    IntPtr sigbus = Marshal.AllocHGlobal (512);
    IntPtr sigsegv = Marshal.AllocHGlobal (512);

    // Store Mono SIGSEGV and SIGBUS handlers
    sigaction (Signal.SIGBUS, IntPtr.Zero, sigbus);
    sigaction (Signal.SIGSEGV, IntPtr.Zero, sigsegv);

    // Enable crash reporting libraries
    EnableCrashReportingUnsafe ();

    // Restore Mono SIGSEGV and SIGBUS handlers            
    sigaction (Signal.SIGBUS, sigbus, IntPtr.Zero);
    sigaction (Signal.SIGSEGV, sigsegv, IntPtr.Zero);

    Marshal.FreeHGlobal (sigbus);
    Marshal.FreeHGlobal (sigsegv);
}

static void EnableCrashReportingUnsafe ()
{
    // Run your crash reporting library initialization code here--
    // this example uses HockeyApp but it should work well
    // with TestFlight or other libraries.

    // Verify in documentation that your library of choice
    // installs its sigaction hooks before leaving this method.

    var manager = BITHockeyManager.SharedHockeyManager;
    manager.Configure (HockeyAppId, null);
    manager.StartManager ();
}

在FinishedLaunching方法的开头调用EnableCrashReporting()。
如果需要，将此调用包装在 #if !DEBUG 指令中。

它是如何工作的？

我听从了 Rolf 的建议:

One possible solution is to allow mono to handle all SIGSEGV signals (technically speaking the crash reporting lib should either not handle the SIGSEGV signal, or it should chain to mono's handler and not do any processing by itself). If mono determines that the SIGSEGV signal is not from managed code (i.e. something very bad happened), it will raise a SIGABORT signal (which the crash reporting lib should already handle and treat as a crash). As you can understand this is something that has to be done in the crash reporting library.

和Landon Fuller的 Objective C 实现:

#import <signal.h>

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    /* Save Mono's signal handler actions */
    struct sigaction sigbus_action, sigsegv_action;
    sigaction(SIGBUS, NULL, &sigbus_action);
    sigaction(SIGSEGV, NULL, &sigsegv_action);

    // Enable the crash reporter here. Ie, [[PLCrashReporter sharedReporter] enableCrashReporterAndReturnError:],
    // or whatever is the correct initialization mechanism for the crash reporting service you're using

    /* Restore Mono's signal handlers */
    sigaction(SIGBUS, &sigbus_action, NULL);
    sigaction(SIGSEGV, &sigsegv_action, NULL);

    return YES;
}

我用了Banshee source code作为如何从 MonoTouch 调用 sigaction 的引用点。

希望对您有所帮助!

关于c# - 如何防止 iOS 崩溃报告器使 MonoTouch 应用程序崩溃？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14499334/