Is there a (legal) way to capture the ENTIRE scree

问题:

I've tried several techniques to capture a screenshot of an app from within that app. None of the techniques appear to capture the status bar -- it ends up being black.

There apparently was once a way to do this, but that interface is internal and Apple will not let you use it.

Any ideas?

Note: This is an attempt to solve this problem, where I need to determine if airplane mode is on or off (and no, simply knowing if the network is reachable is not sufficient).

However, it would seem that this question is of more general interest, and is distinct from that question.

回答1:

Your actual issue, determining if a network interface is active, can be resolved with BSD networking functions. BEHOLD.

#include <sys/socket.h>
#include <ifaddrs.h>
#include <net/if.h>

BOOL IsNICTurnedOn(const char *nicName) {
    BOOL result = NO;

    struct ifaddrs *addrs = NULL;
    if (0 == getifaddrs(&addrs)) {
        for (struct ifaddrs *addr = addrs; addr != NULL; addr = addr->ifa_next) {
            if (0 == strcmp(addr->ifa_name, nicName)) {
                result = (0 != (addr->ifa_flags & (IFF_UP | IFF_RUNNING)));
                break;
            }
        }
        freeifaddrs(addrs);
    }

    return result;
}

To use this function:

BOOL isWWANEnabled = IsNICTurnedOn("pdp_ip0");
BOOL isWiFiEnabled = IsNICTurnedOn("en0");

回答2:

At this point it seems clear that there is no simple way to detect if Airplane Mode is enabled. Although you could probably infer it by looking at low-level network stack info or scraping status bar pixels, either method would be relying on undocumented behavior. It's very possible that on a future release of iOS or a future iOS device, the behavior will change and your code will generate a false positive or false negative.

(Not to mention that, on future devices, the interference may not even be there.)

If I were in your shoes, I would:

1. File a bug to let Apple know you want this feature.

2. Work the notice into the app, regardless of whether Airplane Mode is enabled. Yes, it might be kind of annoying to the user if it is enabled, but the overall harm is minimal. I would probably make this an alert that pops up only once (storing a key in NSUserDefaults to indicate whether its already been displayed).

3. If you want to get super-fancy, analyze the recorded audio and, if the buzz is detected, remind the user again to enable Airplane Mode while recording. You could do this in real time or after the clip has been recorded, whatever makes more sense for your app.

回答3:

As an alternative solution, perhaps you could detect the connection type, similar to: https://developer.apple.com/library/ios/#samplecode/Reachability/Introduction/Intro.html . With some additional checking for the device type, you could then warn the user only in the case where they need to act.

回答4:

Kind of a different approach, but you can also link to pages within the Settings application. You could perhaps link to the primary page and tell the user the changes you require.

回答5:

There appears to be no way to do this.