NSUserActivity handoff not working for custom data

问题

I'm trying to test out the iOS 8.1 handoff feature with NSUserActivity between my iPhone and my iPad. For this, I tried both implementing my own solution, and to use Apple's PhotoHandoff project. However, it's not working.

If I provide a webpageURL, the handover works fine, but when I try to use userData or addUserInfoEntriesFromDictionary nothing works, and I can't for the life of me figure out what the catch is to make the data work.

Sample code:

NSUserActivity *activity = [[NSUserActivity alloc] initWithActivityType:@"com.company.MyTestApp.activity"];
activity.title = @"My Activity";
activity.userInfo = @ {};
//    activity.webpageURL = [NSURL URLWithString:@"http://google.com"];

self.userActivity = activity;

[self.userActivity becomeCurrent];
[self.userActivity addUserInfoEntriesFromDictionary:@ { @"nanananan": @[ @"totoro", @"monsters" ] }];

(I'm also unable to make it work with a Mac app with a corresponding activity type)

回答1:

I hope you found the solution already, but in case somebody stumbles upon this problem too, here is a solution. (Actually not very different from the previous answer)

Create user activity without userInfo, it will be ignored:

NSUserActivity *activity = [[NSUserActivity alloc] initWithActivityType:@"..."];
activity.title = @"Test activity";
activity.delegate = self;
activity.needsSave = YES;

self.userActivity = activity;
[self.userActivity becomeCurrent];

Implement the delegate to react to needSave events:

- (void)userActivityWillSave:(NSUserActivity *)userActivity {
    userActivity.userInfo = @{ @"KEY" : @"VALUE" };
}

When needsSave is set to YES this method will be called and userActivity will be updated.

Hope this helps.

回答2:

To update the activity object’s userInfo dictionary, you need to configure its delegate and set its needsSave property to YES whenever the userInfo needs updating.

This process is described in the best practices section of the Adopting Handoff guide.

For example, with a simple UITextView, you need to specify the activity type ("com.company.app.edit") identifier in the Info.plist property list file in the NSUserActivityTypes array, then:

- (NSUserActivity *)customUserActivity 
{
    if (!_customUserActivity) {
        _customUserActivity = [[NSUserActivity alloc] initWithActivityType:@"com.company.app.edit"];
        _customUserActivity.title = @"Editing in app";
        _customUserActivity.delegate = self;
    }

    return _customUserActivity;
}

- (void)textViewDidBeginEditing:(UITextView *)textView 
{
    [self.customUserActivity becomeCurrent];
}

- (void)textViewDidChange:(UITextView *)textView 
{
    self.customUserActivity.needsSave = YES;
}

- (BOOL)textViewShouldEndEditing:(UITextView *)textView 
{
    [self.customUserActivity invalidate];

    return YES;
}

- (void)userActivityWillSave:(NSUserActivity *)userActivity 
{
    [userActivity addUserInfoEntriesFromDictionary:@{ @"editText" : self.textView.text }];
}

回答3:

FWIW, I was having this issue. I was lucky that one of my Activity types worked and the other didn't:

Activity: Walking
(UserInfo x1,y1)
(UserInfo x2,y2)
(UserInfo x3,y3)
Activity: Standing
(UserInfo x4,y4)
Activity: Walking
etc.

I got userInfo if the handoff occured when standing but not walking. I got other properties such as webpageURL in all cases; just userInfo came through null.

The fix for me was to invalidate & recreate the NSUserActivity object every time (e.g. when Walking to x2/y2 from x1/y1), instead of only when Activity type changed (e.g. from walking to standing). This is very much not the way the doc is written, but fixed the issue on iOS 9.

UPDATE: This workaround doesn't work on iOS 8. You need to implement this via the userActivityWillSave delegate, as gregoryM specified. Per Apple's doc:

To update the activity object’s userInfo dictionary efficiently, configure its delegate and set its needsSave property to YES whenever the userInfo needs updating. At appropriate times, Handoff invokes the delegate’s userActivityWillSave: callback, and the delegate can update the activity state.

This isn't a "best practice", it is required!

[Note: issue occurred on iOS 9 devices running code built on Xcode 6.x. Haven't tested Xcode 7 yet, and issue may not occur on iOS 8.]

来源：https://stackoverflow.com/questions/26715531/nsuseractivity-handoff-not-working-for-custom-data

标签

ios

objective-c

ios8.1

handoff

NSUserActivity