way to update wkinterfacecontroller during runtime in watch os 2

Question

In Header file

#import <WatchKit/WatchKit.h>
#import <Foundation/Foundation.h>
#import <WatchConnectivity/WatchConnectivity.h>

@interface InterfaceController : WKInterfaceController<WCSessionDelegate>
- (IBAction)lastSongButtonClick;
- (IBAction)playSongButtonClick;
- (IBAction)nextSongButtonClick;
@property (strong, nonatomic) IBOutlet WKInterfaceLabel *songTitleLabel;
@property (strong, nonatomic) IBOutlet WKInterfaceButton *playSongButton;

@end

So I implemented the WCSessionDelegate and every time I receive about the UI, I would want it to update. So in my .m file I have:

- (void)session:(nonnull WCSession *)session didReceiveMessage:(nonnull NSDictionary<NSString *,id> *)message{
    NSString* type = [message objectForKey:@"type"];
    if([type isEqualToString:@"UIUpdateInfo"]){
        NSLog(@"Watch receives UI update info");
        [self handleUIUpdateInfo:[message objectForKey:@"content"]];
    }
}

AND

- (void)handleUIUpdateInfo:(NSDictionary*)updateInfo{
    [self.songTitleLabel setText:[updateInfo objectForKey:@"nowPlayingSongTitle"]];
    [self.playSongButton setBackgroundImage:[updateInfo objectForKey:@"playButtonImage"]];
}

However, it doesn't seems to update. Is there any proper way to update?

Answer 1

You're halfway there. You've configured receiving the message on the watch side correctly, but you'll need to trigger a message to be sent when the UI is updated (therefore triggering didReceiveMessage to execute and update the appropriate content).

Where ever you are making changes to the UI, you'll need to include this:

NSDictionary *message = //dictionary of info you want to send
[[WCSession defaultSession] sendMessage:message
                           replyHandler:^(NSDictionary *reply) {
                               //handle reply didReceiveMessage here
                           }
                           errorHandler:^(NSError *error) {
                               //catch any errors here
                           }
 ];

Also, make sure you're activating the WCSession properly. This is usually done in viewDidLoad or willAppear depending on whether you're implementing this on the phone or the watch.

- (void)viewDidLoad {
    [super viewDidLoad];

    if ([WCSession isSupported]) {
        WCSession *session = [WCSession defaultSession];
        session.delegate = self;
        [session activateSession];
    }
}

You can see a full example of an end-to-end Watch to iPhone data transfer in this tutorial - http://www.kristinathai.com/watchos-2-tutorial-using-sendmessage-for-instantaneous-data-transfer-watch-connectivity-1