motionBegan not being called in whole application

Question

Hi all I have an app where I allow the user to post something on their pinwall of facebook. I used the DemoApp directly from Facebook to set it up.

I have implemented a shake detection that does something when the user shakes the device. However, since those two functions are in the same viewcontroller, both of them dont work anymore.

When Facebook pops the login window, the keyboard doesn't appear anymore.
Shakes are not detected anymore.

I suppose it has something to do with the first responders. I have tried a lot of things but I was not able to solve it. Here is the neccessary part of my code.

Post something on facebook pinwall:

- (IBAction)publishStream{

    FactsAppDelegate *appDelegate = (FactsAppDelegate *)[[UIApplication sharedApplication] delegate];
    NSMutableDictionary *dictionary = [[[NSMutableDictionary alloc] init]autorelease];
    [dictionary setObject:@"Du postest diesen Fact:" forKey:@"user_message_prompt"];
    [dictionary setObject:[[appDelegate.facts objectAtIndex:currentFactId] fact] forKey:@"message"];
    [_facebook dialog:@"feed" andParams:dictionary andDelegate:self];
}

Shake detection:

#pragma mark Motion catching
// shake motion began
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if (motion != UIEventSubtypeMotionShake) return;

    // load next fact
    [self next];

    // vibrate
    [self vibrate];
}

Method needed for shake detection:

#pragma mark Shake events are only detectable by the first responder
- (BOOL)canBecomeFirstResponder {
    return YES;
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self becomeFirstResponder];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    [self resignFirstResponder];
}

Can anyone tell me what I have to change to get both (facebook, shake) working? Thanks a lot, doonot

I'd need to see more of your code. A few questions: 1. What are you doing in `[self resignFirstResponder]`? Seems like you could send `resignFirstResponder` directly to the object presenting the keyboard rather than to the view controller itself. 2. How is `publishStream` being invoked? Given that it's an IBOutlet looks like it's either linked to either `action` or `touchUpInside` on a control. — XJones, Apr 04 '11 at 20:36
resignFirstResponder has been inserted to test if it works with that line of code but it didn't. publishStream is invoked when a button in the view is clicked. (touch up inside) — nimrod, Apr 05 '11 at 09:04

XJones · Answer 1 · 2011-04-05T18:27:48.517

I created a simple view based project in XCode and the following works for me. I didn't add Facebook to the mix but the UITextField should simulate it. What this does is:

Touching the UIButton or shaking the device will toggle editing of the UITextField including showing/hiding the keyboard
The UILabel statusLabel will display the last touch or shake action and then timeout to display the default text.

You can create a similar project and copy/paste this in or try to work with your existing app.

EDITED TO ADD .H FILE

Header:

// ShakeShakeShakeViewController.h

#import <UIKit/UIKit.h>

@interface ShakeShakeShakeViewController : UIViewController {
    UITextField *   _textField;
    UILabel *       _statusLabel;
    UIButton *      _actionButton;
}

@property (nonatomic, retain)       IBOutlet UITextField *  textField;
@property (nonatomic, retain)       IBOutlet UILabel *      statusLabel;
@property (nonatomic, retain)       IBOutlet UIButton *     actionButton;

- (IBAction)userInvokedActionWithControl:(id)sender;
- (void)resetStatusLabel;
- (void)toggleTextFieldEditing;

@end

Source:

// ShakeShakeShakeViewController.m

#import "ShakeShakeShakeViewController.h"

@implementation ShakeShakeShakeViewController

@synthesize textField = _textField,
            statusLabel = _statusLabel,
            actionButton = _actionButton;

- (void)dealloc
{
    self.textField = nil;
    self.statusLabel = nil;
    self.actionButton = nil;
    [super dealloc];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [self resetStatusLabel];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    self.textField = nil;
    self.statusLabel = nil;
    self.actionButton = nil;
}

- (void)viewDidAppear:(BOOL)animated
{
    [self becomeFirstResponder];
}

- (IBAction)userInvokedActionWithControl:(id)sender
{
    NSLog(@"Touched");
    self.statusLabel.text = @"Touched";
    [self toggleTextFieldEditing];
}

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event 
{
    if (motion != UIEventSubtypeMotionShake) return;

    NSLog(@"Shaking...");
    self.statusLabel.text = @"Shaking...";
}

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
    if (motion != UIEventSubtypeMotionShake) return;
    NSLog(@"Done shaking...");
    self.statusLabel.text = @"Done shaking";
    [self toggleTextFieldEditing];
}

- (void)toggleTextFieldEditing
{
    if ([self.textField isFirstResponder]) {
        [self becomeFirstResponder];
    }
    else {
        [self.textField becomeFirstResponder];
    }
    [self performSelector:@selector(resetStatusLabel) withObject:nil afterDelay:2];
}

- (void)resetStatusLabel
{
    self.statusLabel.text = @"Shake me";
}

@end

Thanks a lot for your help. Could you shortly post the .h file content? Cheers — nimrod, Apr 05 '11 at 18:02
Thank you. You know, the strange thing in my project is, that the motionBegan action is not called at all when I shake the device. I have no idea were it could fail, the rest looks like your sample project. — nimrod, Apr 05 '11 at 19:08
I have just noticed that when I import your example into my project, shakes are not detected! Having it in a seperate project works.. — nimrod, Apr 05 '11 at 19:54
If motionBegan is not being called something is going on in your project with regard to the responder chain. If you can share your project (or isolated code that I can run that shows the problem) I'll try to help further. — XJones, Apr 05 '11 at 20:24
Hey XJones. Is it still possible to send you my project? I didn't find the problem until now :( — nimrod, May 03 '11 at 14:23
I will set up a github account today and let you know. thanks man — nimrod, May 04 '11 at 14:30

score 0 · Answer 2 · answered Apr 05 '11 at 12:43

0

Try to insert [self becomeFirstResponder] in viewDidAppear

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self becomeFirstResponder];
}

Here the documentation

answered Apr 05 '11 at 12:43

llillo

3
1

I have removed all [self resignFirstResponder]; and added becomeFirstResponder to viewDidAppear but it didn't work. Keyboard doesn't appear. – nimrod Apr 05 '11 at 13:45

score 0 · Accepted Answer · answered May 04 '11 at 19:24

Thanks to XJones I was finally able to fix my problem.

@XJones, I was reducing my app to the default functions and found out why I was not able to catch motions and why I had problems with the facebook keyboard.

My MainWindow.xib file was totally wrong and delegate was not set either. I deleted the xib file, mapped delegate and window and that's it, I can now catch motions and even facebook posting works like a charm :)

Thanks a lot for taking care and offering your help!!

motionBegan not being called in whole application

3 Answers3