键盘添加撤销操作

CustomKeyboard/Utils/KBBackspaceUndoManager.m

@@ -0,0 +1,170 @@
+//
+//  KBBackspaceUndoManager.m
+//  CustomKeyboard
+//
+
+#import "KBBackspaceUndoManager.h"
+#import "KBResponderUtils.h"
+
+NSNotificationName const KBBackspaceUndoStateDidChangeNotification = @"KBBackspaceUndoStateDidChangeNotification";
+
+@interface KBBackspaceUndoManager ()
+@property (nonatomic, strong) NSMutableArray<NSString *> *segments; // deletion order (last -> first)
+@property (nonatomic, assign) BOOL lastActionWasClear;
+@property (nonatomic, assign) BOOL hasUndo;
+@end
+
+@implementation KBBackspaceUndoManager
+
++ (instancetype)shared {
+    static KBBackspaceUndoManager *mgr = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        mgr = [[KBBackspaceUndoManager alloc] init];
+    });
+    return mgr;
+}
+
+- (instancetype)init {
+    if (self = [super init]) {
+        _segments = [NSMutableArray array];
+    }
+    return self;
+}
+
+- (void)recordClearWithContext:(NSString *)context {
+    if (context.length == 0) { return; }
+    NSString *segment = [self kb_segmentForClearFromContext:context];
+    if (segment.length == 0) { return; }
+
+    if (!self.lastActionWasClear) {
+        [self.segments removeAllObjects];
+    }
+    [self.segments addObject:segment];
+    self.lastActionWasClear = YES;
+    [self kb_updateHasUndo:YES];
+}
+
+- (void)performUndoFromResponder:(UIResponder *)responder {
+    if (self.segments.count == 0) { return; }
+    UIInputViewController *ivc = KBFindInputViewController(responder);
+    if (!ivc) { return; }
+    id<UITextDocumentProxy> proxy = ivc.textDocumentProxy;
+    NSString *text = [self kb_buildUndoText];
+    if (text.length == 0) { return; }
+    [proxy insertText:text];
+
+    [self.segments removeAllObjects];
+    self.lastActionWasClear = NO;
+    [self kb_updateHasUndo:NO];
+}
+
+- (void)registerNonClearAction {
+    self.lastActionWasClear = NO;
+    if (self.segments.count == 0) { return; }
+    [self.segments removeAllObjects];
+    [self kb_updateHasUndo:NO];
+}
+
+#pragma mark - Helpers
+
+- (void)kb_updateHasUndo:(BOOL)hasUndo {
+    if (self.hasUndo == hasUndo) { return; }
+    self.hasUndo = hasUndo;
+    [[NSNotificationCenter defaultCenter] postNotificationName:KBBackspaceUndoStateDidChangeNotification object:self];
+}
+
+- (NSString *)kb_segmentForClearFromContext:(NSString *)context {
+    NSInteger length = context.length;
+    if (length == 0) { return @""; }
+
+    static NSCharacterSet *sentenceBoundarySet = nil;
+    static NSCharacterSet *whitespaceSet = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        sentenceBoundarySet = [NSCharacterSet characterSetWithCharactersInString:@".!?;。！？；…\n"];
+        whitespaceSet = [NSCharacterSet whitespaceAndNewlineCharacterSet];
+    });
+
+    NSInteger end = length;
+    while (end > 0) {
+        unichar ch = [context characterAtIndex:end - 1];
+        if ([whitespaceSet characterIsMember:ch]) {
+            end -= 1;
+        } else {
+            break;
+        }
+    }
+    NSInteger searchEnd = end;
+    while (searchEnd > 0) {
+        unichar ch = [context characterAtIndex:searchEnd - 1];
+        if ([sentenceBoundarySet characterIsMember:ch]) {
+            searchEnd -= 1;
+        } else {
+            break;
+        }
+    }
+
+    NSInteger boundaryIndex = NSNotFound;
+    for (NSInteger i = searchEnd - 1; i >= 0; i--) {
+        unichar ch = [context characterAtIndex:i];
+        if ([sentenceBoundarySet characterIsMember:ch]) {
+            boundaryIndex = i;
+            break;
+        }
+    }
+
+    NSInteger start = (boundaryIndex == NSNotFound) ? 0 : (boundaryIndex + 1);
+    if (start >= length) { return @""; }
+    return [context substringFromIndex:start];
+}
+
+- (NSString *)kb_buildUndoText {
+    if (self.segments.count == 0) { return @""; }
+    NSArray<NSString *> *ordered = [[self.segments reverseObjectEnumerator] allObjects];
+    NSMutableString *result = [NSMutableString string];
+    for (NSInteger i = 0; i < ordered.count; i++) {
+        NSString *segment = ordered[i] ?: @"";
+        if (segment.length == 0) { continue; }
+        if (i < ordered.count - 1) {
+            segment = [self kb_replaceTrailingBoundaryWithComma:segment];
+        }
+        [result appendString:segment];
+    }
+    return result;
+}
+
+- (NSString *)kb_replaceTrailingBoundaryWithComma:(NSString *)segment {
+    if (segment.length == 0) { return segment; }
+
+    static NSCharacterSet *boundarySet = nil;
+    static NSCharacterSet *englishBoundarySet = nil;
+    static NSCharacterSet *whitespaceSet = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        boundarySet = [NSCharacterSet characterSetWithCharactersInString:@".!?;。！？；…\n"];
+        englishBoundarySet = [NSCharacterSet characterSetWithCharactersInString:@".!?;"];
+        whitespaceSet = [NSCharacterSet whitespaceAndNewlineCharacterSet];
+    });
+
+    NSInteger idx = segment.length - 1;
+    while (idx >= 0) {
+        unichar ch = [segment characterAtIndex:idx];
+        if ([whitespaceSet characterIsMember:ch]) {
+            idx -= 1;
+            continue;
+        }
+        if (![boundarySet characterIsMember:ch]) {
+            return segment;
+        }
+        NSString *comma = [englishBoundarySet characterIsMember:ch] ? @"," : @"，";
+        NSMutableString *mutable = [segment mutableCopy];
+        NSRange r = NSMakeRange(idx, 1);
+        [mutable replaceCharactersInRange:r withString:comma];
+        return mutable;
+    }
+
+    return segment;
+}
+
+@end