[Tabs] Adjust sizeThatFits: behavior for TabBarView. (#7846)

The `sizeThatFits:` beahvior of `MDCTabBarView` previously would return a size
large enough for Fixed tabs in a justified layout. If the provided `size` was
wider than necessary, that value would be returned.

A solution that works better for inclusion in MDCHeaderStackView, which uses
`sizeThatFits:` to determine the view's frame size.

Closes #7845

MaterialComponentsBeta.podspec

@@ -120,6 +120,8 @@ Pod::Spec.new do |mdc|
       unit_tests.source_files = [
         "components/#{extension.base_name.split('+')[0]}/tests/unit/#{extension.base_name.split('+')[1]}/*.{h,m,swift}",
       ]
+      unit_tests.dependency "MaterialComponents/AppBar"
+      unit_tests.dependency "MaterialComponents/HeaderStackView"
       unit_tests.dependency "MaterialComponents/Typography"
     end
   end

components/Tabs/BUILD

@@ -85,8 +85,8 @@ mdc_extension_objc_library(
     name = "Theming",
     deps = [
         ":Tabs",
-        "//components/schemes/Container",
         "//components/schemes/Color",
+        "//components/schemes/Container",
         "//components/schemes/Typography",
     ],
 )
@@ -186,8 +186,8 @@ mdc_objc_library(
     deps = [
         ":Tabs",
         ":Theming",
-        "//components/schemes/Container",
         "//components/schemes/Color",
+        "//components/schemes/Container",
         "//components/schemes/Typography",
     ],
 )
@@ -225,6 +225,8 @@ mdc_snapshot_objc_library(
         ":Tabs",
         ":Theming",
         ":privateTabBarView",
+        "//components/AppBar",
+        "//components/HeaderStackView",
     ],
 )
 

components/Tabs/src/TabBarView/MDCTabBarView.m

@@ -640,8 +640,8 @@ - (CGSize)intrinsicContentSizeForScrollableLayout {
 }
 
 - (CGSize)sizeThatFits:(CGSize)size {
-  CGSize intrinsicSize = self.intrinsicContentSize;
-  return CGSizeMake(MAX(intrinsicSize.width, size.width), intrinsicSize.height);
+  CGSize fitSize = [self intrinsicContentSizeForJustifiedLayout];
+  return CGSizeMake(size.width, fitSize.height);
 }
 
 #pragma mark - Helpers

components/Tabs/tests/snapshot/TabBarView/MDCTabBarViewIntegrationSnapshotTests.m

@@ -0,0 +1,168 @@
+// Copyright 2019-present the Material Components for iOS authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "MaterialSnapshot.h"
+
+#import "MDCTabBarView.h"
+#import "MaterialAppBar.h"
+#import "MaterialHeaderStackView.h"
+
+/** Snapshot tests for MDCTabBarView when integrating with other components. */
+@interface MDCTabBarViewIntegrationSnapshotTests : MDCSnapshotTestCase
+
+/** The tab bar being tested and integrated. */
+@property(nonatomic, strong) MDCTabBarView *tabBarView;
+
+@end
+
+@implementation MDCTabBarViewIntegrationSnapshotTests
+
+- (void)setUp {
+  [super setUp];
+
+  // Uncomment below to recreate all the goldens (or add the following line to the specific
+  // test you wish to recreate the golden for).
+  //  self.recordMode = YES;
+
+  self.tabBarView = [[MDCTabBarView alloc] init];
+
+  UIImage *typicalIcon = [[UIImage mdc_testImageOfSize:CGSizeMake(24, 24)
+                                             withStyle:MDCSnapshotTestImageStyleFramedX]
+      imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
+
+  UITabBarItem *item1 = [[UITabBarItem alloc] initWithTitle:@"One" image:typicalIcon tag:0];
+  UITabBarItem *item2 = [[UITabBarItem alloc] initWithTitle:@"Two" image:typicalIcon tag:1];
+  UITabBarItem *item3 = [[UITabBarItem alloc] initWithTitle:@"Three" image:typicalIcon tag:2];
+  self.tabBarView.items = @[ item1, item2, item3 ];
+  [self.tabBarView setSelectedItem:item3 animated:NO];
+}
+
+- (void)tearDown {
+  self.tabBarView = nil;
+
+  [super tearDown];
+}
+
+- (void)generateSnapshotAndVerifyForView:(UIView *)view {
+  UIView *snapshotView = [view mdc_addToBackgroundView];
+  [self snapshotVerifyView:snapshotView];
+}
+
+#pragma mark - MDCHeaderStackView Integration
+
+- (void)testTabBarViewInHeaderStackViewBottomBarWithWidthLessThanIntrinsicContentSize {
+  // Given
+  MDCHeaderStackView *headerStackView = [[MDCHeaderStackView alloc] init];
+  headerStackView.backgroundColor = UIColor.orangeColor;
+  CGSize tabBarViewIntrinsicContentSize = self.tabBarView.intrinsicContentSize;
+
+  // When
+  headerStackView.bottomBar = self.tabBarView;
+  headerStackView.bounds = CGRectMake(0, 0, tabBarViewIntrinsicContentSize.width - 50,
+                                      tabBarViewIntrinsicContentSize.height + 50);
+  [headerStackView layoutIfNeeded];
+
+  // Then
+  [self generateSnapshotAndVerifyForView:headerStackView];
+}
+
+- (void)testTabBarViewInHeaderStackViewBottomBarWithWidthEqualToIntrinsicContentSize {
+  // Given
+  MDCHeaderStackView *headerStackView = [[MDCHeaderStackView alloc] init];
+  headerStackView.backgroundColor = UIColor.orangeColor;
+  CGSize tabBarViewIntrinsicContentSize = self.tabBarView.intrinsicContentSize;
+
+  // When
+  headerStackView.bottomBar = self.tabBarView;
+  headerStackView.bounds = CGRectMake(0, 0, tabBarViewIntrinsicContentSize.width,
+                                      tabBarViewIntrinsicContentSize.height + 50);
+  [headerStackView layoutIfNeeded];
+
+  // Then
+  [self generateSnapshotAndVerifyForView:headerStackView];
+}
+
+- (void)testTabBarViewInHeaderStackViewBottomBarWithWidthGreaterThanIntrinsicContentSize {
+  // Given
+  MDCHeaderStackView *headerStackView = [[MDCHeaderStackView alloc] init];
+  headerStackView.backgroundColor = UIColor.orangeColor;
+  CGSize tabBarViewIntrinsicContentSize = self.tabBarView.intrinsicContentSize;
+
+  // When
+  headerStackView.bottomBar = self.tabBarView;
+  headerStackView.bounds = CGRectMake(0, 0, tabBarViewIntrinsicContentSize.width + 50,
+                                      tabBarViewIntrinsicContentSize.height + 50);
+  [headerStackView layoutIfNeeded];
+
+  // Then
+  [self generateSnapshotAndVerifyForView:headerStackView];
+}
+
+#pragma mark - MDCAppBarViewController Integration
+
+- (void)testTabBarViewInAppBarViewBottomBarWithWidthLessThanIntrinsicContentSize {
+  // Given
+  MDCAppBarViewController *appBarController = [[MDCAppBarViewController alloc] init];
+  appBarController.navigationBar.title = @"TabBarView";
+  appBarController.headerView.minimumHeight = 120;
+  appBarController.headerView.backgroundColor = UIColor.orangeColor;
+  CGSize tabBarViewIntrinsicContentSize = self.tabBarView.intrinsicContentSize;
+
+  // When
+  appBarController.headerStackView.bottomBar = self.tabBarView;
+  appBarController.view.bounds = CGRectMake(0, 0, tabBarViewIntrinsicContentSize.width - 50,
+                                            tabBarViewIntrinsicContentSize.height + 50);
+  [appBarController.view layoutIfNeeded];
+
+  // Then
+  [self generateSnapshotAndVerifyForView:appBarController.view];
+}
+
+- (void)testTabBarViewInAppBarViewBottomBarWithWidthEqualToIntrinsicContentSize {
+  // Given
+  MDCAppBarViewController *appBarController = [[MDCAppBarViewController alloc] init];
+  appBarController.navigationBar.title = @"TabBarView";
+  appBarController.headerView.minimumHeight = 120;
+  appBarController.headerView.backgroundColor = UIColor.orangeColor;
+  CGSize tabBarViewIntrinsicContentSize = self.tabBarView.intrinsicContentSize;
+
+  // When
+  appBarController.headerStackView.bottomBar = self.tabBarView;
+  appBarController.view.bounds = CGRectMake(0, 0, tabBarViewIntrinsicContentSize.width,
+                                            tabBarViewIntrinsicContentSize.height + 50);
+  [appBarController.view layoutIfNeeded];
+
+  // Then
+  [self generateSnapshotAndVerifyForView:appBarController.view];
+}
+
+- (void)testTabBarViewInAppBarViewBottomBarWithWidthGreaterThanIntrinsicContentSize {
+  // Given
+  MDCAppBarViewController *appBarController = [[MDCAppBarViewController alloc] init];
+  appBarController.navigationBar.title = @"TabBarView";
+  appBarController.headerView.minimumHeight = 120;
+  appBarController.headerView.backgroundColor = UIColor.orangeColor;
+  CGSize tabBarViewIntrinsicContentSize = self.tabBarView.intrinsicContentSize;
+
+  // When
+  appBarController.headerStackView.bottomBar = self.tabBarView;
+  appBarController.view.bounds = CGRectMake(0, 0, tabBarViewIntrinsicContentSize.width + 50,
+                                            tabBarViewIntrinsicContentSize.height + 50);
+  [appBarController.view layoutIfNeeded];
+
+  // Then
+  [self generateSnapshotAndVerifyForView:appBarController.view];
+}
+
+@end

components/Tabs/tests/snapshot/TabBarView/MDCTabBarViewSnapshotTests.m

@@ -34,6 +34,11 @@
 /** The maximum width of a tab bar item. */
 static const CGFloat kMaxItemWidth = 360;
 
+static inline void SizeViewToIntrinsicContentSize(UIView *view) {
+  CGSize intrinsicContentSize = view.intrinsicContentSize;
+  view.bounds = CGRectMake(0, 0, intrinsicContentSize.width, intrinsicContentSize.height);
+}
+
 /** A custom view to place in an MDCTabBarView. */
 @interface MDCTabBarViewSnapshotTestsCustomView : UIView <MDCTabBarViewCustomViewable>
 /** A switch shown in the view. */
@@ -393,7 +398,7 @@ - (void)testRemovingSelectedItemUpdatesStyle {
   UITabBarItem *item1 = [[UITabBarItem alloc] initWithTitle:@"One" image:self.typicalIcon1 tag:0];
   UITabBarItem *item2 = [[UITabBarItem alloc] initWithTitle:@"Two" image:self.typicalIcon2 tag:1];
   self.tabBarView.items = @[ item1, item2 ];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
   [self.tabBarView setSelectedItem:item1 animated:NO];
   [self.tabBarView setTitleColor:UIColor.blackColor forState:UIControlStateNormal];
   [self.tabBarView setImageTintColor:UIColor.blackColor forState:UIControlStateNormal];
@@ -703,7 +708,7 @@ - (void)testSafeAreaTopAndLeftInsetsForJustifiedLayoutStyle {
   // When
   UIEdgeInsets safeAreaInsets = UIEdgeInsetsMake(16, 44, 0, 0);
   superview.customSafeAreaInsets = safeAreaInsets;
-  CGSize fitSize = [self.tabBarView sizeThatFits:CGSizeZero];
+  CGSize fitSize = self.tabBarView.intrinsicContentSize;
   fitSize = CGSizeMake(fitSize.width + safeAreaInsets.left, fitSize.height + safeAreaInsets.top);
   self.tabBarView.bounds = CGRectMake(0, 0, fitSize.width, fitSize.height);
   superview.bounds = CGRectMake(0, 0, CGRectGetWidth(self.tabBarView.bounds),
@@ -728,7 +733,7 @@ - (void)testSafeAreaRightAndBottomInsetsForJustifiedLayoutStyle {
   // When
   UIEdgeInsets safeAreaInsets = UIEdgeInsetsMake(0, 0, 16, 44);
   superview.customSafeAreaInsets = safeAreaInsets;
-  CGSize fitSize = [self.tabBarView sizeThatFits:CGSizeZero];
+  CGSize fitSize = self.tabBarView.intrinsicContentSize;
   fitSize =
       CGSizeMake(fitSize.width + safeAreaInsets.right, fitSize.height + safeAreaInsets.bottom);
   self.tabBarView.bounds = CGRectMake(0, 0, fitSize.width, fitSize.height);
@@ -817,7 +822,7 @@ - (void)testCustomInsetsTopAndRightRepositionsJustifiedViews {
   // When
   UIEdgeInsets contentInset = UIEdgeInsetsMake(15, 0, 0, 45);
   self.tabBarView.contentInset = contentInset;
-  CGSize fitSize = [self.tabBarView sizeThatFits:CGSizeZero];
+  CGSize fitSize = self.tabBarView.intrinsicContentSize;
   fitSize = CGSizeMake(fitSize.width + contentInset.right, fitSize.height + contentInset.top);
   self.tabBarView.bounds = CGRectMake(0, 0, fitSize.width, fitSize.height);
 
@@ -837,7 +842,7 @@ - (void)testCustomInsetsBottomAndLeftRepositionsJustifiedViews {
   // When
   UIEdgeInsets contentInset = UIEdgeInsetsMake(0, 45, 15, 0);
   self.tabBarView.contentInset = contentInset;
-  CGSize fitSize = [self.tabBarView sizeThatFits:CGSizeZero];
+  CGSize fitSize = self.tabBarView.intrinsicContentSize;
   fitSize = CGSizeMake(fitSize.width + contentInset.left, fitSize.height + contentInset.bottom);
   self.tabBarView.bounds = CGRectMake(0, 0, fitSize.width, fitSize.height);
 
@@ -894,7 +899,7 @@ - (void)testSafeAreaAndContentInsetCombineTopAndLeftForJustifiedLayoutStyle {
   UIEdgeInsets contentInset = UIEdgeInsetsMake(5, 10, 0, 0);
   superview.customSafeAreaInsets = safeAreaInsets;
   self.tabBarView.contentInset = contentInset;
-  CGSize fitSize = [self.tabBarView sizeThatFits:CGSizeZero];
+  CGSize fitSize = self.tabBarView.intrinsicContentSize;
   fitSize = CGSizeMake(fitSize.width + safeAreaInsets.left + contentInset.left,
                        fitSize.height + safeAreaInsets.top + contentInset.top);
   self.tabBarView.bounds = CGRectMake(0, 0, fitSize.width, fitSize.height);
@@ -922,7 +927,7 @@ - (void)testSafeAreaAndContentInsetCombineBottomAndRightForJustifiedLayoutStyle
   UIEdgeInsets contentInset = UIEdgeInsetsMake(0, 0, 5, 10);
   superview.customSafeAreaInsets = safeAreaInsets;
   self.tabBarView.contentInset = contentInset;
-  CGSize fitSize = [self.tabBarView sizeThatFits:CGSizeZero];
+  CGSize fitSize = self.tabBarView.intrinsicContentSize;
   fitSize = CGSizeMake(fitSize.width + safeAreaInsets.right + contentInset.right,
                        fitSize.height + safeAreaInsets.bottom + contentInset.bottom);
   self.tabBarView.bounds = CGRectMake(0, 0, fitSize.width, fitSize.height);
@@ -1050,7 +1055,7 @@ - (void)testSetTitleFontForExplicitItemStates {
   // When
   [self.tabBarView setTitleFont:[UIFont systemFontOfSize:8] forState:UIControlStateNormal];
   [self.tabBarView setTitleFont:[UIFont systemFontOfSize:24] forState:UIControlStateSelected];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
 
   // Then
   [self generateSnapshotAndVerifyForView:self.tabBarView];
@@ -1066,7 +1071,7 @@ - (void)testSetTitleFontForNormalStateAppliesToSelectedItem {
 
   // When
   [self.tabBarView setTitleFont:[UIFont systemFontOfSize:8] forState:UIControlStateNormal];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
 
   // Then
   [self generateSnapshotAndVerifyForView:self.tabBarView];
@@ -1085,7 +1090,7 @@ - (void)testSetTitleFontExplicitlyToNilUsesDefaultFont {
   // When
   [self.tabBarView setTitleFont:nil forState:UIControlStateNormal];
   [self.tabBarView setTitleFont:nil forState:UIControlStateSelected];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
 
   // Then
   [self generateSnapshotAndVerifyForView:self.tabBarView];
@@ -1128,7 +1133,7 @@ - (void)testRippleColor {
   UITabBarItem *item3 = [[UITabBarItem alloc] initWithTitle:@"Three" image:self.typicalIcon3 tag:3];
   self.tabBarView.items = @[ item1, item2, item3 ];
   [self.tabBarView setSelectedItem:item2 animated:NO];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
 
   // When
   self.tabBarView.rippleColor = [UIColor.orangeColor colorWithAlphaComponent:(CGFloat)0.25];
@@ -1145,7 +1150,7 @@ - (void)testCustomSelectionIndicatorStrokeColor {
   UITabBarItem *item3 = [[UITabBarItem alloc] initWithTitle:@"Three" image:self.typicalIcon3 tag:3];
   self.tabBarView.items = @[ item1, item2, item3 ];
   [self.tabBarView setSelectedItem:item2 animated:NO];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
 
   // When
   self.tabBarView.selectionIndicatorStrokeColor = UIColor.purpleColor;
@@ -1161,7 +1166,7 @@ - (void)testSelectionIndicatorStrokeColorResetsToDefault {
   UITabBarItem *item3 = [[UITabBarItem alloc] initWithTitle:@"Three" image:self.typicalIcon3 tag:3];
   self.tabBarView.items = @[ item1, item2, item3 ];
   [self.tabBarView setSelectedItem:item2 animated:NO];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
   self.tabBarView.selectionIndicatorStrokeColor = UIColor.purpleColor;
 
   // When
@@ -1178,7 +1183,7 @@ - (void)testBottomDividerColor {
   UITabBarItem *item3 = [[UITabBarItem alloc] initWithTitle:@"Three" image:self.typicalIcon3 tag:3];
   self.tabBarView.items = @[ item1, item2, item3 ];
   [self.tabBarView setSelectedItem:item2 animated:NO];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
   self.tabBarView.bottomDividerColor = UIColor.purpleColor;
 
   // When
@@ -1201,7 +1206,7 @@ - (void)testCustomView {
 
   // When
   self.tabBarView.items = @[ item1, customViewItem, item3 ];
-  [self.tabBarView sizeToFit];
+  SizeViewToIntrinsicContentSize(self.tabBarView);
 
   // Then
   [self generateSnapshotAndVerifyForView:self.tabBarView];

components/Tabs/tests/unit/TabBarView/MDCTabBarViewTests.m

@@ -679,15 +679,15 @@ - (void)testIntrinsicContentSizeDeterminedByJustifiedViewNotScrollableView {
   XCTAssertGreaterThanOrEqual(actualIntrinsicContentSize.height, intrinsicSizeMinimalSize.height);
 }
 
-- (void)testSizeThatFitsExpandsToFitContent {
+- (void)testSizeThatFitsFitsOnlyIncreasesHeightForTooSmallSize {
   // Given
   self.tabBarView.items = @[ self.itemA ];
 
   // When
   CGSize size = [self.tabBarView sizeThatFits:CGSizeZero];
 
   // Then
-  XCTAssertGreaterThan(size.width, 0);
+  XCTAssertEqualWithAccuracy(size.width, 0, 0.001);
   XCTAssertEqualWithAccuracy(size.height, kMinHeight, 0.001);
 }