Cocoa NSUndoManager重做准备InvocationTarget

使用

prepareWithInvocationTarget

使用我的方法，重做不起作用（撤消起作用）

---

在undo方法中，如果从undo调用，则应注册一个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];

}

- (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];

}