近期在bug后台收到一条NSInternalInconsistencyException导致闪退的记录。
出错堆栈如下：-[AVCaptureStillImageOutput captureStillImageAsynchronouslyFromConnection:completionHandler:] Inconsistent state
同时注意到该错误全部发生在iPad上。
最后查到原因是在iPad上开启了画中画的情况下，使用AVCaptureSession拍照由于session处于被interrupt的状态，所以会导致闪退。还有其他的原因例如打电话，闹铃，处在分屏模式下等。
解决办法：在session startRunning前添加AVCaptureSessionWasInterrupted通知的观察。样例代码如下：
#pragma mark - Session Notifications
- (void) addObservers
{
/*
A session can only run when the app is full screen. It will be interrupted
in a multi-app layout, introduced in iOS 9, see also the documentation of
AVCaptureSessionInterruptionReason. Add observers to handle these session
interruptions and show a preview is paused message. See the documentation
of AVCaptureSessionWasInterruptedNotification for other interruption reasons.
*/
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionWasInterrupted:) name:AVCaptureSessionWasInterruptedNotification object:self.session];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionInterruptionEnded:) name:AVCaptureSessionInterruptionEndedNotification object:self.session];
}
- (void) removeObservers
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (void) sessionWasInterrupted:(NSNotification*)notification
{
AVCaptureSessionInterruptionReason reason = [notification.userInfo[AVCaptureSessionInterruptionReasonKey] integerValue];
NSLog(@"Capture session was interrupted with reason %ld", (long)reason);
//在此禁止掉拍照功能，同时添加提醒
if (reason == AVCaptureSessionInterruptionReasonAudioDeviceInUseByAnotherClient ||
reason == AVCaptureSessionInterruptionReasonVideoDeviceInUseByAnotherClient) {
}
else if (reason == AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps) {
}
else if (@available(iOS 11.1, *)) {
if (reason == AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableDueToSystemPressure) {
}
} else {
// Fallback on earlier versions
}
}
- (void) sessionInterruptionEnded:(NSNotification*)notification
{
//在此可以恢复拍照功能
}
具体可以查看苹果的样例代码
