NSUndoManager恢复使用InvocationTarget准备

Question

使用prepareWithInvocationTarget 时，我如何设置与设置撤消操作相同的特定重做操作

使用我的方法，重做不起作用（撤消起作用）

- (void)removeSmth:(Smth *)smth index:(NSInteger)indexOfSmth {
    [self.document.undoManager beginUndoGrouping];
    ...
    [self removeSmth:smth];
    [[self.document.undoManager prepareWithInvocationTarget:self] undoInsertSmth:smth index:indexOfSmth];
    ...
    [self.document.undoManager endUndoGrouping];
}
- (void)undoInsertSmth:(Smth *)smth index:(NSUInteger)index {
    [self insertSmth:smth index:index];
}

Answer 1

在undo方法中，如果从unding调用，则应注册undo

- (void)removeSmth:(Smth *)smth index:(NSInteger)indexOfSmth {
    [self.document.undoManager beginUndoGrouping];
    ...
    [self removeSmth:smth];
    [[self.document.undoManager prepareWithInvocationTarget:self] undoInsertSmth:smth index:indexOfSmth];
    ...
    [self.document.undoManager endUndoGrouping];
}
- (void)undoInsertSmth:(Smth *)smth index:(NSUInteger)index {
    if ([self.document.undoManager isUndoing]) {
        [[self.document.undoManager prepareWithInvocationTarget:self] removeSmth:smth index:index];
    }
    [self insertSmth:smth index:index];
}