iOS：请求访问相机

Question

iOS：请求访问相机

14

我有一个带有QR码扫描器的应用程序，在大多数情况下运行正常，但在iOS 8上，默认访问相机被设置为“拒绝”。因此，我不得不进入设置，手动允许应用程序访问相机。如何使提示出现，类似于“是否要允许此应用程序访问相机”？

这里是我的代码示例，检查摄像头权限，如果用户没有授予权限则请求权限。然而，给予权限的链接从未出现，最终只显示UIAlertView。测试时状态确实为DENIED，那么它没有请求权限的原因是什么？谢谢！

同时，我已经#import了AVFoundation/AVFoundation.h，所以那不是问题所在。

-(void) checkCameraAuthorization {

AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

if(status == AVAuthorizationStatusAuthorized) { // authorized
    NSLog(@"camera authorized");
}
else if(status == AVAuthorizationStatusDenied){ // denied
    if ([AVCaptureDevice respondsToSelector:@selector(requestAccessForMediaType: completionHandler:)]) {
        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
            // Will get here on both iOS 7 & 8 even though camera permissions weren't required
            // until iOS 8. So for iOS 7 permission will always be granted.

            NSLog(@"DENIED");

            if (granted) {
                // Permission has been granted. Use dispatch_async for any UI updating
                // code because this block may be executed in a thread.
                dispatch_async(dispatch_get_main_queue(), ^{
                    //[self doStuff];
                });
            } else {
                // Permission has been denied.
                UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Not Authorized" message:@"Please go to Settings and enable the camera for this app to use this feature." delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
                [alert show];
            }
        }];
    }
}
else if(status == AVAuthorizationStatusRestricted){ // restricted
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Not Authorized" message:@"Please go to Settings and enable the camera for this app to use this feature." delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
    [alert show];
}
else if(status == AVAuthorizationStatusNotDetermined){ // not determined

    [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
        if(granted){ // Access has been granted ..do something
            NSLog(@"camera authorized");
        } else { // Access denied ..do something
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Not Authorized" message:@"Please go to Settings and enable the camera for this app to use this feature." delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
            [alert show];
        }
    }];
}
}

- MSU_Bulldog

在此处回答：https://dev59.com/iGAf5IYBdhLWcg3w0Vi7 - Samhan Salahuddin

2个回答

2

对于Swift 3：

UIApplication.shared.openURL(URL(string: UIApplicationOpenSettingsURLString)!)

欲了解更多，请查看此视频 https://www.youtube.com/watch?v=Btd1XH-gHKM

- Eduardo Oliveros

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Dan Loughney · Accepted Answer

听起来这个应用程序已经被拒绝访问相机了。在这种情况下，您无法再次发出提示。每次安装后，您只能提示用户访问一次。之后，您需要指导用户前往设置。

将用户发送到您的设置页面，在 iOS8 上可以通过以下方式启用相机：

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];

如果您在测试，请尝试从手机中删除应用程序，然后再安装并再次运行它。这会将您重新置于“AVAuthorizationStatusNotDetermined”状态。