Adding a New ScreenΒΆ

Once you have your app all set up and configured, the most common task you will want to do is add a new screen. Fortunately, this is quite easy!

First, come up with a short name that you would like to identify this new screen, which we refer to as the “slug”, and the Objective-C class name. For example if you are creating a screen to present a photo to the user, you might choose photo as your slug, and you might want to choose something like PhotoViewController for your new file in XCode.

To help make this easier, we’ve created a tool to help get the details right. All you have to do is enter your choices below:

Now you should type this command into (make sure you change to the directory holding your Clutch JavaScript first):

clutch startscreen $SLUG$

Now you should go to your XCode project and add a new file. Choose “UIViewController subclass” when it asks. Name it what you decided above, and then copy this into $NAME$.h:

#import <UIKit/UIKit.h>
#import <Clutch/Clutch.h>

@interface $NAME$ : UIViewController <ClutchViewDelegate>

@property (nonatomic, retain) ClutchView *clutchView;


Now copy this into $NAME$.m:

#import "$NAME$.h"

@implementation $NAME$

@synthesize clutchView = _clutchView;

- (void)didReceiveMemoryWarning
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.

#pragma mark - ClutchViewDelegate

- (void)clutchView:(ClutchView *)clutchView
      methodCalled:(NSString *)method
        withParams:(NSDictionary *)params
          callback:(void(^)(id))callback {
    // Handle any events coming from the JavaScript of your Clutch view here
    if([method isEqualToString:@"tapped"]) {
        NSLog(@"Tapped: %@\n", [params objectForKey:@"value"]);

#pragma mark - View lifecycle

- (void)loadView
    self.view = [[[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    self.clutchView = [[ClutchView alloc] initWithFrame:CGRectMake(0, 0, 320, 367)
    [self.clutchView release];
    self.clutchView.delegate = self;
    [self.view addSubview:self.clutchView];

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
    [super viewDidLoad];

- (void)viewDidUnload
    [super viewDidUnload];
    self.clutchView = nil;

- (void)viewDidAppear:(BOOL)animated
    [super viewDidAppear:animated];
    [self.clutchView viewDidAppear:animated];

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];
    [self.clutchView viewDidDisappear:animated];

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);


This is a standard UIViewController subclass, which instantiates a single ClutchView instance and adds it to the view, sets itself up as a delegate to handle events that come in from the JavaScript layer, and passes along any viewDidAppear: and viewDidDisappear: messages into the Clutch view.

That’s it! You’ve got your screen hooked up and now it’s up to you to use it for good, not evil.

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