1

我有一个 MonoTouch 应用程序，它由许多视图组成，每个视图都有一个关联的界面和演示者。它看起来像这样：

class SomeView : UIView, ISomeView
{
    public event EventHandler PreviousClicked = delegate {};
    public event EventHandler NextClicked = delegate {};
    public event EventHandler Loaded = delegate {};

    public SomeView()
    {
        new SomePresenter(this);
    }
}

interface ISomeView
{
    event EventHandler PreviousClicked;
    event EventHandler NextClicked;
    event EventHandler Loaded;
    event EventHandler Unloaded;
}

class SomePresenter
{
    readonly ISomeView _view;

    public SomePresenter(ISomeView view)
    {
        _view = view;
        _view.Loaded += Loaded; 
        _view.NextClicked += NextClicked;
        _view.PreviousClicked += PreviousClicked;
        _view.Unloaded += Unloaded;
    }

    void Loaded (object sender, EventArgs e)
    {
        //Nothing special
    }

    void PreviousClicked (object sender, EventArgs e)
    {
        //Nothing special
    }

    void NextClicked (object sender, EventArgs e)
    {
        //Nothing special
    }
}

此代码在模拟器中完美运行，但是在 iPad 上运行时，当演示者在其构造函数中将事件附加到视图时，它将崩溃。但它以一种非常非常奇怪的方式崩溃。

首先，它不会在附加第一个事件而是第二个事件时崩溃，即

_view = view;
_view.Loaded += Loaded; 
_view.NextClicked += NextClicked; //FAILS HERE

它返回的堆栈跟踪是

0   SomeApp              0x008f8e01 mono_handle_native_sigsegv + 244
1   SomeApp              0x0092b511 sigabrt_signal_handler + 112
2   libsystem_c.dylib    0x321817ed _sigtramp + 48
3   libsystem_c.dylib    0x3217720f pthread_kill + 54
4   libsystem_c.dylib    0x3217029f abort + 94
5   SomeApp              0x008ceccb monoeg_g_log + 122
6   SomeApp              0x008d386b get_numerous_trampoline + 134
7   SomeApp              0x008d3b33 mono_aot_get_imt_thunk + 34
8   SomeApp              0x00921be5 initialize_imt_slot + 72
9   SomeApp              0x0092294f build_imt_slots + 642
10  SomeApp              0x00922a29 mono_vtable_build_imt_slot + 80
11  SomeApp              0x008fd90d mono_convert_imt_slot_to_vtable_slot + 212
12  SomeApp              0x008fdab9 common_call_trampoline + 180
13  SomeApp              0x008fc78b mono_vcall_trampoline + 158
14  SomeApp              0x005ec748 generic_trampoline_vcall + 136
...

应该注意的是，这些视图中的每一个都被推送到 UINavigationController 中，并且演示者可以完美地将事件附加到视图，直到两个视图被推送到堆栈上。

我最初的假设是 GC 正在积极收集内存，但后来我尝试删除接口并将事件附加到具体类型上，即

public SomePresenter(SomeView view)
{
    _view = view;
    _view.Loaded += Loaded; 
    _view.NextClicked += NextClicked; 
    _view.PreviousClicked += PreviousClicked;
    _view.Unloaded += Unloaded;
}

一切正常。幽灵般的

如果有人知道这里发生了什么，我真的很想听听！

4

1 回答 1

5

设备日志通常会显示一条消息，解释有关问题的更多信息。您可以从 MonoDevelop 访问设备（菜单 View -> Pads -> iOS Device Log）。

设备日志可能会说您需要增加特定类型的蹦床的数量，您可以在此处阅读：http: //docs.xamarin.com/ios/troubleshooting#Ran_out_of_trampolines_of_type_0

于 2012-11-16T12:46:43.140 回答