How do I respond to the user shaking an iPhone? - objective-c

Question

Alright, so to get going with Objective-C (I'm usually just an HTML PhoneGap kinda guy), I made a simple Magic 8 ball app. I've got it right now so that when I touch the screen, the ball "shakes" and takes a random response and puts it in a label. What I want to do is when the iPhone itself is shaked, the text is updated too.
Here's my MainView.m:
#import "MainView.h"
#implementation MainView
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
if (event.type == UIEventSubtypeMotionShake) {
int rNumber = rand() % 26;
switch (rNumber) {
case 0:
shook.text = #"Never";
break;
....25 more entries.....
default:
break;
}
}
}
- (IBAction)yesNo {
[NSThread sleepForTimeInterval:0.75];
int rNumber = rand() % 26;
switch (rNumber) {
case 0:
result.text = #"Never";
break;
........
default:
break;
}
}
#end
and my MainView.h
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#interface MainView : UIView <UIAccelerometerDelegate> {
IBOutlet UILabel *result;
IBOutlet UILabel *shook;
}
- (IBAction)yesNo;
- (void)motionEnded;
#end
Obviously there's an error in there, I know that much, but where?!

Answer 1

It looks like you need to read the documentation in more depth to get to the bottom of this. Specifically the iOS Event Handling Guide.
From that document there are a few things which I would suggest you try:
Override canBecomeFirstResponder: and return YES (as per Listing 4-1).
Override viewDidAppear:animated: to become the first responder (as per Listing 4-1).
Override both motionBegan:withEvent: and motionCancelled:withEvent: as they do this in the example which may be because the framework is testing your view controller class to see if it responds to these selectors (as per Listing 4-2).
Look at the UIResponder Class Reference (from which UIViewController inherits) for more detail on the methods you are overriding.
As someone who came from a Microsoft / VB / .NET and Android / Java background to Cocoa / Objective-C programming I would strongly suggest you invest the time in reading the documentation. Initially the Apple documents seem impenetrable but they're actually pretty good!
I hope that helps.