We can add the following type of initializers to a class with extensions:
Convenience initializers.
Designated initializers.
Primary initializers.
We can add the following type of properties to a class with extensions:
Read/write stored type properties.
Primary properties.
Computed instance properties and computed type properties.
Convenience initializers are:
Optional.
Required.
Required only in superclasses.
A convenience initializer acts as:
A required initializer that doesn't need to call any other initializer.
A secondary initializer that doesn't need to call any other initializer.
A secondary initializer that always ends up calling a designated initializer.
If we declare the type for a property as
UIPickerView!
, Swift will treat the property as:An implicitly wrapped optional.
An implicitly unwrapped optional.
An exact equivalent of
UIPickerView?
.
Argentina
Australia
Austria
Belgium
Brazil
Bulgaria
Canada
Chile
Colombia
Cyprus
Czechia
Denmark
Ecuador
Egypt
Estonia
Finland
France
Germany
Great Britain
Greece
Hungary
India
Indonesia
Ireland
Italy
Japan
Latvia
Lithuania
Luxembourg
Malaysia
Malta
Mexico
Netherlands
New Zealand
Norway
Philippines
Poland
Portugal
Romania
Russia
Singapore
Slovakia
Slovenia
South Africa
South Korea
Spain
Sweden
Switzerland
Taiwan
Thailand
Turkey
Ukraine
United States