How to activate app's running instance

Question

imneo OP

Created Dec ’16

Replies 4

Boosts 0

Views 1.2k

Participants 4

Hope my scenario is not weird. Here is the description:

1. User runs my app.

2. User hides my app completely (all windows are hidden) so that he/she has no way to accessing the app. (Dont' ask why, user requested this feature and I want to implement it.)

3. Now user rerun my app and I want to use XPC to tell the running instance to show itself.

It sounds very reasonable and I have done most of code. But it is blocked by macOS the system. It seems macOS controls only one instnace of an app can be running at the same time; second try to run the same app (in /Applications) simply does nothing - the app code does not even get executed so that my code in main.m won't have the change to communicate with XPC.

I believe there must be a way to overcome this. Any suggestions will be appreciated. Thanks and Merry Xmas!

Answered by DTS Engineer in 203447022

I hide all windows completely from dock using a method like below

Just by by of terminology, this isn’t ‘hiding all windows’, this is transforming your process into a what’s commonly called a UI element, that is, a GUI that has no normal UI. UI elements can display UI, but don’t show up in the Dock, or when you hit command-Tab, and so on.

I had to test this to confirm, but it turns out that UI elements do get the

-applicationShouldHandleReopen:hasVisibleWindows:

delegate callback when the user double clicks the app in the Finder, so it seems that like that’s the best way forward.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Boost

Answer 1

pmills OP

Dec ’16

I would expect your running app to get app delegate callbacks for applicationDidUnhide or applicationDidBecomeActive (or both). Do you implement those?

0

Answer 2

DTS Engineer OP

Apple

Dec ’16

2. User hides my app completely (all windows are hidden) so that he/she has no way to accessing the app.

Does your app show up in the Dock?

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

0

Answer 3

imneo OP

Dec ’16

Oh, I forgot to mention this. I hide all windows completely from dock using a method like below:

+ (BOOL)hideWindowFromDock:(NSWindow *)window
{
    if ([NSApp activationPolicy] != NSApplicationActivationPolicyProhibited)
    {
        [NSApp setActivationPolicy:NSApplicationActivationPolicyProhibited];
    }
    [window setIsVisible:NO];
    return YES;
}

0

Answer 4

KMT OP

Dec ’16

>User hides my app completely (all windows are hidden) so that he/she has no way to accessing the app.

Even via cmd-tab? Or Apple logo/recent items?

0