UIImagePickerController偶尔冻结 [英] UIImagePickerController occasionally freezing up

问题描述

我在Unity应用程序中使用UIImagePickerController.用户按下完成"时，它有时会冻结.它最经常在3GS上发生-大约每三次-但我偶尔在iPhone 5上也死机.此错误在iOS上从4.3到7.0出现.我无法确定与冻结有关的因素.冻结时我也没有收到内存警告.

I use UIImagePickerController in an Unity app. It occasionally freezes when the user presses "done". It happens most often on 3GS — about every third time — but I also had an occasional freeze on iPhone 5. This bug appears on iOS from 4.3 to 7.0. I wasn't able to determine what factors correlate with the freeze. I don't get a memory warning when I get this freeze either.

日志中没有错误，也没有崩溃日志.该应用程序继续像往常一样在UIImagePickerController之后运行.控制台中似乎有很多相关的消息，例如"deny file-write-data/private/var/mobile/Media/PhotoData"，但是当出现冻结或一切正常时，所有这些消息有时都会出现好吧.

There are no errors in the log, no crashlog whatsoever. The app continues to run behind UIImagePickerController as normal. There are a lot of messages in the console that seem related, like "deny file-write-data /private/var/mobile/Media/PhotoData", but all of them can occasionally appear both when freeze is present and when everything is working alright.

这是我显示选择器的方式:

Here's how I show the picker:

- (void)showPicker:(UIImagePickerControllerSourceType)type
{
    imgPicker = [[[CustomPhotoPicker alloc] init] autorelease];
    imgPicker.delegate = self;
    imgPicker.sourceType = type;
    imgPicker.allowsEditing = _pickerAllowsEditing;

    // wrap and show the modal
    [self showViewControllerModallyInWrapper:imgPicker];

}

这是委托方法:

- (void)imagePickerController:(UIImagePickerController*)imgPicker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
    NSLog( @"imagePickerController didFinishPickingMediaWithInfo");

    // If the freeze is present, this method isn't called
}

- (void)imagePickerController:(UIImagePickerController *)imgPicker
        didFinishPickingImage:(UIImage *)image
                  editingInfo:(NSDictionary *)editingInfo
{
    NSLog( @"imagePickerController didFinishPickingImage");

    // Tried to use deprecated callback. If the freeze is present, this method isn't called either.
}

我认为这是UIImagePickerController内部的一个错误，但是没有使用Unity的iOS开发人员都没有遇到过此问题，并且我认为如果在4.3中存在此错误，则该错误已经得到修复.

I would decide that it's a bug inside the UIImagePickerController, but none of iOS developers that don't use Unity ever encountered this problem, and I would suppose that such a bug would already be fixed if it was present in 4.3.

推荐答案

有一个解决方法:您可以在UnityAppController.mm中将CFRunLoopRunInMode静音，如下所示:

Thre're are a workaround: u can mute CFRunLoopRunInMode in UnityAppController.mm, like this:

- (void)repaintDisplayLink
{
    [_displayLink setPaused: YES];
    {
        static const CFStringRef kTrackingRunLoopMode = CFStringRef(UITrackingRunLoopMode);
        if (![EtceteraManager picking])
        {
            while (CFRunLoopRunInMode(kTrackingRunLoopMode, kInputProcessingTime, TRUE) == kCFRunLoopRunHandledSource)
                ;
        }
    }
}

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