IOHIDEventSystemClientScheduleWithRunLoop与EXC

本文介绍了IOHIDEventSystemClientScheduleWithRunLoop与EXC_BAD_ACCESS的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在尝试在我的应用程序中获取触摸事件。所以我使用IOHIDFamily回调来获取事件。我的代码是这样的：

I'm trying to get touch events in my application. So I used the IOHIDFamily callback to get the events. My code is like this:

void handle_event(void* target, void* refcon, IOHIDServiceRef service, IOHIDEventRef event) { printf("Received event of type %2d from service %p.\n", IOHIDEventGetType(event), service); } - (void)viewDidLoad { [super viewDidLoad]; void *ioHIDEventSystem = IOHIDEventSystemClientCreate(kCFAllocatorDefault); IOHIDEventSystemClientScheduleWithRunLoop(system, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode); IOHIDEventSystemClientRegisterEventCallback(system, handle_event, NULL, NULL); CFRunLoopRun(); }

执行时出错：

IOHIDEventSystemClientScheduleWithRunLoop（system，CFRunLoopGetCurrent（），kCFRunLoopDefaultMode）;

IOHIDEventSystemClientScheduleWithRunLoop(system, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

IOKit`IOHIDEventSystemClientScheduleWithRunLoop： ... 0x32f8fd14：cmp.w r10，＃0 0x32f8fd18：strd r10，r11，[r4，＃116]< --- EXC_BAD_ACCESS（代码= EXC_ARM_DA_ALIGN） 0x32f8fd1c：beq 0x32f8fdac; IOHIDEventSystemClientScheduleWithRunLoop + 168 0x32f8fd1e：ldr r1，[r4，＃96] 0x32f8fd20：cbz r1,0x32f8fd2a; IOHIDEventSystemClientScheduleWithRunLoop + 38 0x32f8fd22：mov r0，r10 ...

IOKit`IOHIDEventSystemClientScheduleWithRunLoop: ... 0x32f8fd14: cmp.w r10, #0 0x32f8fd18: strd r10, r11, [r4, #116] <---EXC_BAD_ACCESS(code=EXC_ARM_DA_ALIGN) 0x32f8fd1c: beq 0x32f8fdac ; IOHIDEventSystemClientScheduleWithRunLoop + 168 0x32f8fd1e: ldr r1, [r4, #96] 0x32f8fd20: cbz r1, 0x32f8fd2a ; IOHIDEventSystemClientScheduleWithRunLoop + 38 0x32f8fd22: mov r0, r10 ...

我以错误的方式使用IOHIDFamily？

Did I use IOHIDFamily in the wrong way?

推荐答案

我发现代码中至少有几个问题：

There's at least a couple problems I see in the code posted:

首先，您正在致电

CFRunLoopRun();

$ b

在 viewDidLoad 方法中在main / UI线程上调用。我认为没有理由，所以只需删除该行。我通常希望看到那个调用，如果你有一个方法，你在后台线程上运行，你需要启动后台运行循环。或者，如果您直接在 main（）中注册回调，请回答。

in the viewDidLoad method, which is going to be called on the main/UI thread. I see no reason for that, so just remove that line. I'd normally expect to see that call if you had a method that you were running on a background thread, and you needed to start a background run loop. Or, if you were registering for callbacks directly in main(), as in this answer.

然后，你有这个：

void *ioHIDEventSystem = IOHIDEventSystemClientCreate(kCFAllocatorDefault); IOHIDEventSystemClientScheduleWithRunLoop(system, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

我猜第二行应该是

IOHIDEventSystemClientScheduleWithRunLoop(ioHIDEventSystem, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

我不知道系统是什么变量实际上是指，但它看起来不正确。

I don't know what the system variable actually refers to, but it doesn't look right.

参加看看最近的答案，因为它似乎正确使用 IOKit 。

Take a look at this recent answer, as it seems to use IOKit correctly.