UIMenuController 聊天时的复制、删除、撤回

![Uploading 屏幕快照 2016-11-08 下午12.35.00_719577.png . . .]

屏幕快照 2016-11-08 下午12.35.00.png

喏，就是这个小东西，聊天的时候我们都用到了，实际开发中好像不太常用。它叫做UIMenuController，下面分享它的使用。
一般是在长按的时候会出现这个小菜单，那么就需要在长安出现菜单的控件上加一个手势：

[view addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)]];

让后我们来实现这个longPress:方法:

- (void)longPress:(UILongPressGestureRecognizer *)longRecognizer {
    if (longRecognizer.state == UIGestureRecognizerStateBegan) {
        [view becomeFirstResponder];
        UIMenuController *menu = [UIMenuController sharedMenuController];
        UIMenuItem *copyItem = [[UIMenuItem alloc] initWithTitle:@"复制" action:@selector(copyItemClicked:)];
        UIMenuItem *deleteItem = [[UIMenuItem alloc] initWithTitle:@"删除" action:@selector(deleteItemClicked:)];
        [menu setMenuItems:[NSArray arrayWithObjects:copyItem, deleteItem, nil]];
        CGRect rect = view.bounds;
        rect.origin.y = rect.origin.y - SCALE6P(10);
        rect.size.height = rect.size.height + SCALE6P(20);
        [menu setTargetRect:rect inView:view];
        [menu setMenuVisible:YES animated:YES];
    }
}

写好这些以后，长按那个 view ，UIMenuController并没有出现！还要加点几行。

#pragma mark 处理action事件
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
    if (action == @selector(copyItemClicked:)) {
        return YES;
    } else if (action == @selector(deleteItemClicked:)){
        return YES;
    }
    return [super canPerformAction:action withSender:sender];
}

#pragma mark 实现成为第一响应者方法
- (BOOL)canBecomeFirstResponder {
    return YES;
}

让添加了UIMenuController的view响应才可以出现那个小黑框，但是点击复制和删除当然就没什么作用了。要实现@selector(copyItemClicked:)和@selector(deleteItemClicked:)方法才行啊！

- (void)deleteItemClicked:(id)sender {
    NSLog(@"删除");
   // 做删除，一般是tableView中删除某一行，不要忘记删除数据源在reload data 就好了。
        NSIndexPath *indexPath ; // 计算你的tableView的indexPath
        [self.list removeObjectAtIndex:indexPath.row];
        [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}

- (void)copyItemClicked:(id)sender {
    NSLog(@"复制");
    UIPasteboard *pasteBoard = [UIPasteboard generalPasteboard];
    pasteBoard.string = youView.text;
}

OK，现在复制、删除的功能基本实现了。你可以在自己的工程中试试了。