material-components_material-components-ios/components/Tabs

Tabs

Tabs are bars of buttons used to navigate between groups of content.

Design & API documentation

• Material Design guidelines: Tabs
• Class: MDCTabBarUnderlineIndicatorTemplate
• Class: MDCTabBar
• Class: MDCTabBarIndicatorAttributes
• Class: MDCTabBarViewController
• Protocol: MDCTabBarControllerDelegate
• Protocol: MDCTabBarDelegate
• Protocol: MDCTabBarIndicatorContext
• Protocol: MDCTabBarIndicatorTemplate
• Enumeration: Enumerations
• Enumeration: MDCTabBarAlignment
• Enumeration: MDCTabBarItemAppearance
• Enumeration: MDCTabBarItemState
• Enumeration: MDCTabBarTextTransform

Table of contents

• Overview
• Installation
  • Installation with CocoaPods
  • Importing
• Usage
  • Importing
  • Delegate
  • Selected item
  • Appearance
  • Styling
  • Custom selection indicators
  • Bottom navigation
• Examples
  • Creating a tab bar
• Extensions
  • Color Theming
  • Typography Theming

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Overview

When a user taps a tab, the content changes to match the selected subject in the tabs.

We provide this functionality through MDCTabBar which communicates via a delegate as well as MDCTabBarViewController which provides a view containment model similar to UITabViewController.

Tabs can also show a badge (usually a number) like UITabBar.

Installation

Installation with CocoaPods

Add the following to your Podfile:

pod 'MaterialComponents/Tabs'

Then, run the following command:

pod install

Importing

To import the component:

Swift

import MaterialComponents.MaterialTabs

Objective-C

#import "MaterialTabs.h"

Usage

Importing

To use the tab bar in your code, import the MaterialTabs umbrella header (Objective-C) or MaterialComponents module (Swift).

Swift

import MaterialComponents

Objective-C

#import "MaterialTabs.h"

Delegate

Conform your class to the MDCTabBarDelegate protocol and set it as the tab bar's delegate to handle updating the UI when the user selects a tab.

Selected item

Update the selected tab programmatically by setting selectedItem, optionally with an animation. Delegate methods are not called for programmatic changes, so callers are responsible for updating UI as needed after updating the selected item.

Appearance

Set the itemAppearance property on the tab bar to switch between item display modes. Items can be displayed as titles (the default), icons, or combined.

Styling

By default, the tab bar is configured to display items with white text and icons. To customize the color of the tab bar, set the tintColor, selectedItemTintColor, unselectedItemTintColor, inkColor, and barTintColor properties. If selectedItemTintColor is nil, the tab bar's tintColor will be used automatically for selected items.

Configure where items are placed in the tab bar by setting the alignment property.

Custom selection indicators

The currently-selected tab is indicated visually by a selection indicator. By default this is an underline, but you can customize its appearance by defining a selection indicator template and setting the selectionIndicatorTemplate property on the tab bar. Template objects are provided contextual information about a tab's content and return attributes that describe how that tab's indicator should appear. The indicator will then automatically display the provided shape and animate changes as the user selects different tabs.

See MDCTabBarIndicatorTemplate and MDCTabBarIndicatorAttributes for details.

Bottom navigation

Implement positionForBar: and return UIBarPositionBottom to configure the tab bar as a bottom navigation bar. The bar will automatically update with the appropriate styling.

Examples

Creating a tab bar

Swift

let tabBar = MDCTabBar(frame: view.bounds)
tabBar.items = [
UITabBarItem(title: "Recents", image: UIImage(named: "phone"), tag: 0),
UITabBarItem(title: "Favorites", image: UIImage(named: "heart"), tag: 0),
]
tabBar.itemAppearance = .titledImages
tabBar.autoresizingMask = [.flexibleWidth, .flexibleBottomMargin]
tabBar.sizeToFit()
view.addSubview(tabBar)

Objective-C

MDCTabBar *tabBar = [[MDCTabBar alloc] initWithFrame:self.view.bounds];
tabBar.items = @[
    [[UITabBarItem alloc] initWithTitle:@"Recents" image:[UIImage imageNamed:@"phone"] tag:0],
    [[UITabBarItem alloc] initWithTitle:@"Favorites" image:[UIImage imageNamed:@"heart"] tag:0],
];
tabBar.itemAppearance = MDCTabBarItemAppearanceTitledImages;
tabBar.autoresizingMask =
    UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleBottomMargin;
[tabBar sizeToFit];
[self.view addSubview:tabBar];

Extensions

Color Theming

You can theme a tab bar with your app's color scheme using the ColorThemer extension.

You must first add the Color Themer extension to your project:

pod 'MaterialComponents/Tabs+ColorThemer'

Swift

// Step 1: Import the ColorThemer extension
import MaterialComponents.MaterialTabs_ColorThemer

// Step 2: Create or get a color scheme
let colorScheme = MDCSemanticColorScheme()

// Step 3: Apply the color scheme to your component
// Primary variant
MDCTabBarColorThemer.applySemanticColorScheme(colorScheme, toTabs: component)
// Or surface variant
MDCTabBarColorThemer.applySurfaceVariant(withColorScheme: colorScheme, toTabs: component)

Objective-C

// Step 1: Import the ColorThemer extension
#import "MaterialTabs+ColorThemer.h"

// Step 2: Create or get a color scheme
id<MDCColorScheming> colorScheme = [[MDCSemanticColorScheme alloc] init];

// Step 3: Apply the color scheme to your component
// Primary variant
[MDCTabBarColorThemer applySemanticColorScheme:colorScheme toTabs:component];
// Or surface variant
[MDCTabBarColorThemer applySurfaceVariantWithColorScheme:colorScheme toTabs:component];

Typography Theming

You can theme a tab bar with your app's typography scheme using the TypographyThemer extension.

You must first add the Typography Themer extension to your project:

pod 'MaterialComponents/Tabs+TypographyThemer'

Swift

// Step 1: Import the TypographyThemer extension
import MaterialComponents.MaterialTabs_TypographyThemer

// Step 2: Create or get a typography scheme
let typographyScheme = MDCTypographyScheme()

// Step 3: Apply the typography scheme to your component
MDCTabBarTypographyThemer.applyTypographyScheme(typographyScheme, to: component)

Objective-C

// Step 1: Import the TypographyThemer extension
#import "MaterialTabs+TypographyThemer.h"

// Step 2: Create or get a typography scheme
id<MDCTypographyScheming> typographyScheme = [[MDCTypographyScheme alloc] init];

// Step 3: Apply the typography scheme to your component
[MDCTabBarTypographyThemer applyTypographyScheme:colorScheme
     toTabBar:component];