fix bug of iOS 14 beta 6 navigation bar weird behavior. (#157)

Author: Liaoworking

KMNavigationBarTransition/UINavigationBar+KMNavigationBarTransition.m

@@ -22,6 +22,8 @@
 //  THE SOFTWARE.
 
 #import "UINavigationBar+KMNavigationBarTransition.h"
+#import "UINavigationBar+KMNavigationBarTransition_internal.h"
+#import "KMWeakObjectContainer.h"
 #import <objc/runtime.h>
 #import "KMSwizzle.h"
 
@@ -35,6 +37,13 @@ + (void)load {
                         @selector(layoutSubviews),
                         [self class],
                         @selector(km_layoutSubviews));
+        // fix the bug of iOS14 beta 6
+        if (@available(iOS 14.0, *)) {
+          KMSwizzleMethod([self class],
+                          NSSelectorFromString(@"_accessibility_navigationController"),
+                          [self class],
+                          @selector(km_accessibility_navigationController));
+        }
     });
 }
 #endif
@@ -55,4 +64,24 @@ - (void)setKm_isFakeBar:(BOOL)hidden {
     objc_setAssociatedObject(self, @selector(km_isFakeBar), @(hidden), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 }
 
+- (UINavigationController *) km_accessibility_navigationController {
+  UINavigationController * navigationController = [self km_accessibility_navigationController];
+  if (self.km_isFakeBar) {
+      // if it's fake navigation bar
+      // return previously bound navigationController.
+    return self.km_fakeController;
+  }
+  return navigationController;
+}
+
+- (UINavigationController *)km_fakeController
+{
+  return km_objc_getAssociatedWeakObject(self, @selector(km_fakeController));
+}
+
+- (void)setKm_fakeController:(UINavigationController *)km_fakeController
+{
+  km_objc_setAssociatedWeakObject(self, @selector(km_fakeController), km_fakeController);
+}
+
 @end

KMNavigationBarTransition/UINavigationBar+KMNavigationBarTransition_internal.h

@@ -26,5 +26,7 @@
 @interface UINavigationBar (KMNavigationBarTransition_internal)
 
 @property (nonatomic, assign) BOOL km_isFakeBar;
+// store current navigation controller.
+@property (nonatomic, weak) UINavigationController *km_fakeController;
 
 @end

KMNavigationBarTransition/UIViewController+KMNavigationBarTransition.m

@@ -128,6 +128,9 @@ - (void)km_addTransitionNavigationBarIfNeeded {
     [self km_adjustScrollViewContentOffsetIfNeeded];
     UINavigationBar *bar = [[UINavigationBar alloc] init];
     bar.km_isFakeBar = YES;
+    if (@available(iOS 14.0, *)) {
+      bar.km_fakeController = self.navigationController;
+    }
     bar.barStyle = self.navigationController.navigationBar.barStyle;
     if (bar.translucent != self.navigationController.navigationBar.translucent) {
         bar.translucent = self.navigationController.navigationBar.translucent;