当iOS应用程序最小化时,如何从相机拍照?
(即在applicationDidEnterBackground:
/ applicationWillResignActive:
之后)
AppDelegate.m:(感谢链接)
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//To make the code block asynchronous
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//### background task starts
NSLog(@"Running in the background\n");
while(TRUE)
{
printf("Called"); //////Work fine
[self.window.rootViewController captureNow]; /////Capture picture!
[NSThread sleepForTimeInterval: 10.0]; //wait for 10 sec
}
});
return YES;
}
OurViewController.m: (thank you link)
-(IBAction)captureNow {
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in _stillImageOutput.connections)
{
for (AVCaptureInputPort *port in [connection inputPorts])
{
if ([[port mediaType] isEqual:AVMediaTypeVideo] )
{
videoConnection = connection;
break;
}
}
if (videoConnection)
{
break;
}
}
NSLog(@"about to request a capture from: %@", _stillImageOutput);
[_stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
{
CFDictionaryRef exifAttachments = CMGetAttachment( imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
if (error)
{
NSLog(@"ERROR = %@", error); ///// Error!
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer]; ////SIGABRT, cause imageSampleBuffer is nil
UIImage *image = [[UIImage alloc] initWithData:imageData];
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
[image release];
}];
}
这段代码在应用程序处于活动状态时可以正常工作,但是当应用程序最小化时会出现错误(SIGABRT)。
也许有其他的库可以胜任这项任务?