iOS 11: Delete Backwards Workaround

Aztec/Classes/TextKit/TextView.swift

@@ -457,7 +457,9 @@ open class TextView: UITextView {
 
         ensureRemovalOfParagraphStylesBeforeRemovingCharacter(at: selectedRange)
 
-        super.deleteBackward()
+        preserveTypingAttributes {
+            super.deleteBackward()
+        }
 
         ensureRemovalOfParagraphAttributesWhenPressingBackspaceAndEmptyingTheDocument()
         ensureCursorRedraw(afterEditing: deletedString.string)
@@ -967,6 +969,28 @@ open class TextView: UITextView {
     }
 
 
+    // WORKAROUND: iOS 11 introduced an issue that's causing UITextView to lose it's typing
+    // attributes under certain circumstances. This method will determine the Typing Attributes based on
+    /// the TextStorage attributes, whenever possible.
+    ///
+    /// Issue: https://github.com/wordpress-mobile/AztecEditor-iOS/issues/749
+    ///
+    private func preserveTypingAttributes(beforeDeletion block: () -> Void) {
+        let document = textStorage.string
+        guard selectedRange.location == document.characters.count else {
+            block()
+            return
+        }
+
+        let previousLocation = max(selectedRange.location - 1, 0)
+        let previousAttributes = textStorage.attributes(at: previousLocation, effectiveRange: nil)
+
+        block()
+
+        typingAttributes = previousAttributes
+    }
+
+
     // MARK: - Links
 
     /// Adds a link to the designated url on the specified range.

AztecTests/TextKit/TextViewTests.swift

@@ -1409,6 +1409,9 @@ class TextViewTests: XCTestCase {
         XCTAssertEqual(textView.text, Constants.sampleText0 + Constants.sampleText1 + String(.lineFeed) + String(.paragraphSeparator))
     }
 
+
+    // MARK: - Media
+
     func testInsertVideo() {
         let textView = createEmptyTextView()
         let _ = textView.replaceWithVideo(at: NSRange(location:0, length:0), sourceURL: URL(string: "video.mp4")!, posterURL: URL(string: "video.jpg"), placeHolderImage: nil)
@@ -1447,6 +1450,9 @@ class TextViewTests: XCTestCase {
         XCTAssertEqual(textView.getHTML(), "<p><video src=\"newVideo.mp4\" poster=\"video.jpg\" data-wpvideopress=\"ABCDE\"></video></p>")
     }
 
+
+    // MARK: - Comments
+
     /// This test check if the insertion of a Comment Attachment works correctly and the expected tag gets inserted
     ///
     func testInsertComment() {
@@ -1470,6 +1476,9 @@ class TextViewTests: XCTestCase {
         XCTAssertEqual(html, "<p><!--some other comment should go here--><!--more--></p>")
     }
 
+
+    // MARK: - HR
+
     /// This test check if the insertion of an horizontal ruler works correctly and the hr tag is inserted
     ///
     func testReplaceRangeWithHorizontalRuler() {
@@ -1571,6 +1580,9 @@ class TextViewTests: XCTestCase {
         XCTAssertEqual(textView.getHTML(), "<p><img src=\"image.jpg\" class=\"alignnone wp-image-169\" alt=\"Changed Alt\" title=\"Title\"></p>")
     }
 
+
+    // MARK: - Bugfixing
+
     /// This test verifies that the H1 Header does not get lost during the Rich <> Raw transitioning.
     ///
     func testToggleHtmlWithTwoEmptyLineBreaksDoesNotLooseHeaderStyle() {
@@ -1664,4 +1676,27 @@ class TextViewTests: XCTestCase {
         let expected = "<ol><li><ol><li><ol><li><blockquote>First Item</blockquote></li></ol></li></ol></li></ol>"
         XCTAssert(textView.getHTML(prettyPrint: false) == expected)
     }
+
+    /// This test verifies that the `deleteBackward` call does not result in loosing the Typing Attributes.
+    /// Precisely, we'll ensure that the Italics style isn't lost after hitting backspace, and retyping the
+    /// deleted character.
+    ///
+    /// Ref. Issue #749: Loosing Style after hitting Backspace
+    ///
+    func testDeleteBackwardsDoesNotEndUpLoosingItalicsStyle() {
+        let textView = createTextView(withHTML: "")
+
+        textView.toggleBoldface(self)
+        textView.insertText("First Line")
+        textView.insertText("\n")
+
+        textView.toggleItalics(self)
+        textView.insertText("Second")
+
+        let expectedHTML = textView.getHTML(prettyPrint: false)
+        textView.deleteBackward()
+        textView.insertText("d")
+
+        XCTAssertEqual(textView.getHTML(prettyPrint: false), expectedHTML)
+    }
 }