UIKit is\u00a0“the cornerstone of creating user interfaces in all iOS apps”, according to the Apple documentation. Here are some notes on some elements of UIKit…<\/p>\n
To iterate through all the views\/controls in a ViewController, use a loop, through the subviews. The following code searches for all the buttons in the ViewController, and if the title of the button is a ‘+’, sets the title to “0”:<\/p>\n
for view in self.view.subviews as! [UIView] { \/\/ 1\r\n if let btn = view as? UIButton { \/\/ 2\r\n if btn.currentTitle == \"+\" { \/\/ 3\r\n btn.setTitle(\"O\", forState: .Normal) \/\/ 4\r\n }\r\n }\r\n}\r\n<\/pre>\nPeculiar to Swift\/IOS are ‘as!<\/strong>‘, ‘as?<\/strong>‘,\u00a0UIView<\/strong>,\u00a0UIButton<\/strong>\u00a0and\u00a0subviews<\/strong>.<\/p>\n\n- Apple has documented the\u00a0UIView class<\/a>\u00a0and\u00a0Windows and Views<\/a>.<\/li>\n
- For an explanation of why ‘as!<\/strong>‘ is used, helpful is\u00a0Apple’s documentation on\u00a0Type Casting<\/a>, and a\u00a0page of their blog<\/a>.<\/li>\n
- \u00a0Optionals is explained at\u00a0Apple<\/a>, and by\u00a0Andrew Wagner<\/a>.<\/li>\n<\/ul>\n
Referring to the code above:<\/p>\n
\n- The\u00a0currentTitle<\/strong>\u00a0property returns the title that is displayed on the UIButton. See the\u00a0Apple documentation<\/a>\u00a0for other title properties.<\/li>\n
- The\u00a0setTitle<\/strong>\u00a0method takes the following forState parameters: .Normal, .Highlighted, .Disabled, .Selected, .Application, and .Reserved.<\/li>\n<\/ol>\n
Creating an Alert Message<\/h3>\n
The order of events is:<\/p>\n
\n- Create and define a\u00a0UIAlertController<\/strong><\/li>\n
- Create and define a\u00a0UIAlertAction<\/strong><\/li>\n
- Pass the action to the\u00a0UIAlertController<\/strong>\u00a0using it’s\u00a0addAction<\/strong>\u00a0method<\/li>\n
- Show the Alert Message using\u00a0presentViewController<\/strong>.<\/li>\n
- And to close the Alert Message (with animation, use true below), call<\/li>\n<\/ol>\n
dismissViewControllerAnimated(true, completion: nil)<\/pre>\nNote that\u00a0presentViewController<\/strong>\u00a0returns immediately, and programme execution continues with the statement following\u00a0presentViewController<\/strong>. That is, Alert Messages are shown asynchronously.<\/p>\n\n- UIAlertController<\/strong>, which is available in IOS 8.0 and later, is the Alert Message Controller, and displays an alert message to the user, with the provided title, message, and\u00a0style. Possible styles are\u00a0.Alert<\/strong>, and\u00a0.ActionSheet<\/strong>. For example:<\/li>\n<\/ul>\n
let alert = UIAlertController(title: \"Hello, World\", message: \"This is my first app!\", preferredStyle: .Alert)<\/pre>\n
\n- UIAlertAction<\/strong>, is the action assigned to a button in the Alert Message. The parameters passed to the button are the title of the button, \u00a0the style of the button, and a function to perform an action when the user touches the button. Possible styles are\u00a0.Default<\/strong>,\u00a0.Cancel<\/strong>, and\u00a0.Destructive<\/strong>. .Cancel will display a style which indicates to the user that the operation will be cancelled and things will remain unchanged, while .Destructive will display a style which indicates to the user that data will be changed or deleted. For example:<\/li>\n<\/ul>\n
func someHandler<\/span>(<\/span>alert<\/span>:<\/span> UIAlertAction<\/span>!)<\/span> {<\/span>\r\n \/\/ Do something...<\/span>\r\n}\r\n\r\n<\/span><\/code>let action = UIAlertAction(title: \"Awesome!\", style: .Default, handler: someHandler)<\/pre>\nYou tell the Alert Controller about the Alert Action by passing the action using the addAction method. For example, using the above two examples:<\/p>\n
alert.addAction(action)<\/pre>\n
\n- presentViewController<\/strong>\u00a0commands IOS to display the Alert Message and the Alert Action(s) defined above. The parameters to pass to\u00a0presentViewController are the configured UIAlertController, whether to animate the presentation (true or false), and a function (with no parameters and does not return a value) to execute upon completion of the presentation. For example, using the examples above:<\/li>\n<\/ul>\n
presentViewController(alert, animated: true, completion: nil)<\/pre>\nDimensions of IOS devices<\/h3>\n\n- iPhone 3GS and older (3.5″) – 320×480 points – 1 pixel \/ point<\/li>\n
- iPhone 4 and 4S (3.5″) – 320×480\u00a0points – 2 pixels \/ point<\/li>\n
- iPhone 5, 5c and 5s (4″) – 320×568\u00a0points\u00a0– 2 pixels \/ point<\/li>\n
- iPhone 6 (4.7″) – 375×667\u00a0points\u00a0– 2 pixels \/ point<\/li>\n
- iPhone 6 Plus (5.5″) – 414×736\u00a0points\u00a0– 3 pixels \/ point<\/li>\n
- iPad (all models) (7.9″ and 9.7″) – 768×1024\u00a0points\u00a0– 2 pixels \/ point (although iPad 2 and mini only have 1 pixel \/ point)<\/li>\n<\/ul>\n
Note, when creating images, there are 2 pixels per point. For example, a background image for the iPhone 4S will be 640×960 pixels.<\/p>\n
For app icon sizes (and others) see IOS Human Interface Guidelines<\/a>.<\/p>\nAdding images to Sliders<\/h3>\n
For example:<\/p>\n
let thumbImageNormal = UIImage(named: \"SliderThumb-Normal\") slider.setThumbImage(thumbImageNormal, forState: .Normal)\r\n\r\nlet thumbImageHighlighted = UIImage(named: \"SliderThumb-Highlighted\")\r\n\r\nslider.setThumbImage(thumbImageHighlighted, forState: .Highlighted)\r\n\r\nlet insets = UIEdgeInsets(top: 0, left: 14, bottom: 0, right: 14)\r\n\r\nif let trackLeftImage = UIImage(named: \"SliderTrackLeft\") {\r\n let trackLeftResizable =\r\n trackLeftImage.resizableImageWithCapInsets(insets)\r\n slider.setMinimumTrackImage(trackLeftResizable, forState: .Normal)\r\n}\r\n\r\nif let trackRightImage = UIImage(named: \"SliderTrackRight\") {\r\n let trackRightResizable =\r\n trackRightImage.resizableImageWithCapInsets(insets)\r\n slider.setMaximumTrackImage(trackRightResizable, forState: .Normal)\r\n}<\/pre>\nThe above code sets normal and highlighted images for the thumb, and sets different images for the left and right side of the track. Insets are the size of the edges not to be altered when stretching the image to fit the track. See Natasha The Robot<\/a> for more information.<\/p>\n","protected":false},"excerpt":{"rendered":"UIKit is\u00a0“the cornerstone of creating user interfaces in all iOS apps”, according to the Apple documentation. Here are some notes on some elements of UIKit… Iterating through the views To iterate through all the views\/controls in a ViewController, use a loop, through the subviews. The following code searches for all the buttons in the ViewController, … Continue reading “UIKit”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":341,"parent":336,"menu_order":5,"comment_status":"open","ping_status":"open","template":"","meta":{"ngg_post_thumbnail":0,"jetpack_post_was_ever_published":false,"footnotes":""},"class_list":["post-487","page","type-page","status-publish","has-post-thumbnail","hentry"],"featured_image_src":"https:\/\/i0.wp.com\/gregvinall.com\/wp\/wp-content\/uploads\/2015\/06\/Swift-Cover-Photo1.jpg?resize=600%2C153&ssl=1","featured_image_src_square":"https:\/\/i0.wp.com\/gregvinall.com\/wp\/wp-content\/uploads\/2015\/06\/Swift-Cover-Photo1.jpg?resize=600%2C153&ssl=1","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/P7Q68N-7R","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/pages\/487","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/comments?post=487"}],"version-history":[{"count":14,"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/pages\/487\/revisions"}],"predecessor-version":[{"id":522,"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/pages\/487\/revisions\/522"}],"up":[{"embeddable":true,"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/pages\/336"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/media\/341"}],"wp:attachment":[{"href":"https:\/\/gregvinall.com\/wp\/wp-json\/wp\/v2\/media?parent=487"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}