iOS Custom Keyboard - camera not working

问题

I want to create a custom keyboard, that acts as a barcode scanner. I already did the whole coding, but the output is not as expected: I am being asked for camera permissions (the first time), but the camera sends no video to the view.

I think, that there might be some restrictions using keyboards for safety reasons?!?

1.) Turn on the torch

-(void) turnFlashOn
{
    AVCaptureDevice *flashLight = [AVCaptureDevice
                                   defaultDeviceWithMediaType:AVMediaTypeVideo];
    if([flashLight isTorchAvailable] && [flashLight
                                         isTorchModeSupported:AVCaptureTorchModeOn])
    {
        BOOL success = [flashLight lockForConfiguration:nil];
        if(success){
            NSError *error;
            [flashLight setTorchMode:AVCaptureTorchModeOn];
            [flashLight setTorchModeOnWithLevel:1.0 error:&error];
            NSLog(@"Error: %@", error);
            [flashLight unlockForConfiguration];
            NSLog(@"flash turned on -> OK");

        }
        else
        {
            NSLog(@"flash turn on -> ERROR");
        }
    }

}

This gives me this log output, but nothing happens with the flash:

Error: (null)
flash turned on -> OK

2.) Scan the barcode (part of viewDidLoad)

    // SCANNER PART
self.captureSession = [[AVCaptureSession alloc] init];
AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];
if(videoInput)
    [self.captureSession addInput:videoInput];
else
    NSLog(@"Error: %@", error);

AVCaptureMetadataOutput *metadataOutput = [[AVCaptureMetadataOutput alloc] init];
[self.captureSession addOutput:metadataOutput];
[metadataOutput setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[metadataOutput setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode, AVMetadataObjectTypeEAN13Code]];

AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];

camView = [[UIView alloc] initWithFrame: [[UIScreen mainScreen] bounds]];
previewLayer.frame = camView.layer.bounds;
[camView.layer addSublayer:previewLayer];
self.keyboard.barcodeView.clipsToBounds=YES;
camView.center = CGPointMake(self.keyboard.barcodeView.frame.size.width/2, self.keyboard.barcodeView.frame.size.height/2);

[self.keyboard.barcodeView addSubview:camView];

And if I press a special key on my keyboard this one is called:

-(void)scanBarcodeNow{
AudioServicesPlaySystemSound(systemSoundTock);
NSLog(@"Start scanning...");
self.keyboard.barcodeView.hidden=false;
[self.keyboard.barcodeView addSubview:camView];
[self.keyboard.barcodeView setBackgroundColor:[UIColor redColor]];
[self.captureSession startRunning];

}

The only thing happens, is that the keyboard.barcodeView changes its background color to red. I've made this to see, that all the wiring that I've done should be Ok. But no video from the cam is shown....

Can anyone help me out?

回答1:

The reason you're getting back null is because you don't have access to it. It's actually not a bug. According to Apple guidelines certain APIs are not available to iOS 8 extensions (See bullet #3 below).

It sucks, but I always encourage people to read up on new features and see if what they want to do is possible, before dwelling into an idea (Saves a lot of time). Definitely check out the App Extension Programming Guide for more information.

来源：https://stackoverflow.com/questions/25957524/ios-custom-keyboard-camera-not-working

标签

ios

keyboard

ios8

barcode

avcapturesession