[Dialogs] Implement MDCAlertController typography themer. (#3302)

* Implementing MDCAlertTypographyThemer.

* fixed the test.

* Implementing MDCAlertTypographyThemer.

* fixed the test.

* Dialogs: Example for typography added.

MaterialComponents.podspec

@@ -308,7 +308,15 @@ Pod::Spec.new do |mdc|
       extension.dependency "MaterialComponents/Dialogs"
       extension.dependency "MaterialComponents/Themes"
     end
-  end
+    component.subspec "TypographyThemer" do |extension|
+      extension.ios.deployment_target = '8.0'
+      extension.public_header_files = "components/Dialogs/src/#{extension.base_name}/*.h"
+      extension.source_files = "components/Dialogs/src/#{extension.base_name}/*.{h,m}"
+
+      extension.dependency "MaterialComponents/Dialogs"
+      extension.dependency "MaterialComponents/schemes/Typography"
+    end
+ end
 
   mdc.subspec "FeatureHighlight" do |component|
     component.ios.deployment_target = '8.0'

components/Dialogs/BUILD

@@ -67,6 +67,21 @@ mdc_objc_library(
     visibility = ["//visibility:public"],
 )
 
+mdc_objc_library(
+    name = "TypographyThemer",
+    srcs = native.glob(["src/TypographyThemer/*.m"]),
+    hdrs = native.glob(["src/TypographyThemer/*.h"]),
+    includes = ["src/TypographyThemer"],
+    sdk_frameworks = [
+        "UIKit",
+    ],
+    deps = [
+        ":Dialogs",
+        "//components/schemes/Typography",
+    ],
+    visibility = ["//visibility:public"],
+)
+
 mdc_objc_library(
     name = "private",
     hdrs = native.glob(["src/private/*.h"]),
@@ -88,6 +103,7 @@ mdc_objc_library(
     deps = [
         ":Dialogs",
         ":ColorThemer",
+        ":TypographyThemer",
         ":private",
     ],
     visibility = ["//visibility:private"],

components/Dialogs/examples/DialogsAlertViewController.m

@@ -17,6 +17,7 @@
 #import "supplemental/DialogsAlertViewControllerSupplemental.h"
 #import "MaterialButtons.h"
 #import "MaterialDialogs.h"
+#import "MDCAlertTypographyThemer.h"
 
 @implementation DialogsAlertViewController
 
@@ -66,6 +67,9 @@ - (IBAction)didTapShowAlert {
 
   MDCAlertController *materialAlertController =
       [MDCAlertController alertControllerWithTitle:titleString message:messageString];
+  MDCTypographyScheme *typographyScheme = [[MDCTypographyScheme alloc] init];
+  [MDCAlertTypographyThemer applyTypographyScheme:typographyScheme
+                                toAlertController:materialAlertController];
 
   MDCAlertAction *agreeAaction = [MDCAlertAction actionWithTitle:@"AGREE"
                                                          handler:^(MDCAlertAction *action) {

components/Dialogs/src/TypographyThemer/MDCAlertTypographyThemer.h

@@ -0,0 +1,35 @@
+/*
+ Copyright 2018-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 <UIKit/UIKit.h>
+
+#import "MaterialDialogs.h"
+#import "MaterialTypographyScheme.h"
+
+/**
+ Used to apply a typography scheme to theme a MDCAlertController alert dialogs.
+ */
+@interface MDCAlertTypographyThemer : NSObject
+
+/**
+ Applies a typography scheme to theme a MDCAlertController alert dialogs.
+ 
+ @param typographyScheme The typography scheme to apply to a MDCAlertController alert dialogs.
+ */
++ (void)applyTypographyScheme:(nonnull id<MDCTypographyScheming>)typographyScheme
+            toAlertController:(nonnull MDCAlertController *)alertController;
+
+@end

components/Dialogs/src/TypographyThemer/MDCAlertTypographyThemer.m

@@ -0,0 +1,28 @@
+/*
+ Copyright 2018-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 "MDCAlertTypographyThemer.h"
+
+@implementation MDCAlertTypographyThemer
+
++ (void)applyTypographyScheme:(nonnull id<MDCTypographyScheming>)typographyScheme
+            toAlertController:(nonnull MDCAlertController *)alertController {
+  alertController.titleFont = typographyScheme.headline6;
+  alertController.messageFont = typographyScheme.body1;
+  alertController.buttonFont = typographyScheme.button;
+}
+
+@end

components/Dialogs/tests/unit/MDCAlertControllerTypographyThemerTests.m

@@ -0,0 +1,44 @@
+/*
+ Copyright 2018-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 "MaterialDialogs.h"
+#import "MDCAlertTypographyThemer.h"
+
+#import "MDCAlertControllerView+Private.h"
+
+#import <XCTest/XCTest.h>
+
+@interface MDCAlertControllerTypographyThemerTests : XCTestCase
+
+@end
+
+@implementation MDCAlertControllerTypographyThemerTests
+
+- (void)testApplyingTypographyScheme {
+  MDCAlertController *alert = [MDCAlertController alertControllerWithTitle:@"title"
+                                                                   message:@"message"];
+  MDCTypographyScheme *typographyScheme = [[MDCTypographyScheme alloc] init];
+  [MDCAlertTypographyThemer applyTypographyScheme:typographyScheme toAlertController:alert];
+
+  MDCAlertControllerView *view = (MDCAlertControllerView *)alert.view;
+  XCTAssertEqual(view.titleLabel.font, typographyScheme.headline6);
+  XCTAssertEqual(view.messageLabel.font, typographyScheme.body1);
+  for (UIButton *button in view.actionButtons) {
+    XCTAssertEqual(button.titleLabel.font, typographyScheme.button);
+  }
+}
+
+@end