Dropdown for selecting an item from a larger set.

Dropdowns allow a user to make a selection from a predefined set of options. When presented on the screen, only the selected option (or a placeholder) is visible. When the dropbox is tapped, a UIPickerView is presented from the bottom of the user’s screen, allowing them to scroll through all of the available options.


Any text can be set as a dropbox option, though long strings will truncate to fit a single line in the pickerView. Therefore, option titles should be as brief as is practicable.

Dropdown options

let dropbox = Dropbox(optionTitles: ["Thing 1", "Thing 2"])


Dropdowns can be initialized with a placeholder string. The placeholder text is visible before the user has made any selection, but is not a selectable option in the pickerview, and thus can never be reselected by the user. The default placeholder text is “Choose one…”, but it can be set to a more descriptive value.

Dropdown placeholder

dropbox.placeholder = "Pick a thing"


Dropdowns support the following four states: default, highlighted, error, disabled.


A dropbox in it’s normal state.

Default dropdown

dropbox.isEnabled = true
dropbox.hasError = false
dropbox.isHighlighted = false


The active dropbox with which the user is interacting. A dropbox will enter this state when tapped.

Highlighted dropdown

dropbox.isEnabled = true
dropbox.hasError = false
dropbox.isHighlighted = true


A dropbox that is failing some validation and needs a users attention.

Error dropdown

dropbox.isEnabled = true
dropbox.hasError = true


A dropdown that cannot be selected by the user. This may be the case when the dropbox only applies to a path other than the one that the user has chosen.

Disabled dropdown

dropbox.isEnabled = false
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