显示UIMenuController丢失键盘

Question

我正在创建一个类似于手机上的消息应用程序的iPhone应用程序.我只是设置了通过UIMenuController复制消息的能力,但是如果键盘正在显示并且有人试图复制消息,键盘就会消失(大概是因为我[cell becomeFirstResponder];在哪里cell复制了消息单元).

有没有办法显示复制邮件而不会丢失键盘？

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:
(NSIndexPath *)indexPath {

    //...other cell setup stuff...

    UILongPressGestureRecognizer *longPressGesture =
    [[UILongPressGestureRecognizer alloc]
      initWithTarget:self action:@selector(showCopyDialog:)];
    [cell addGestureRecognizer:longPressGesture];

    return cell;
}

- (void)showCopyDialog:(UILongPressGestureRecognizer *)gesture
{
    if (gesture.state == UIGestureRecognizerStateBegan)
    {
        ConvoMessageCell *cell = (ConvoMessageCell *)[gesture view];
        NSIndexPath *indexPath = [self.tblConvo indexPathForCell:cell];

        UIMenuController *theMenu = [UIMenuController sharedMenuController];
        [cell becomeFirstResponder];
        [theMenu setTargetRect:CGRectMake(menuX, menuY, 100, 100) inView:cell];
        [theMenu setMenuVisible:YES animated:YES];        
    }
}

Answer 1

我通过继承UITextView以提供一种覆盖nextResponder并禁用内置操作(Paste)的方法来解决这个难题,如下所示:

@interface CustomResponderTextView : UITextView

@property (nonatomic, weak) UIResponder *overrideNextResponder;

@end

@implementation CustomResponderTextView

@synthesize overrideNextResponder;

- (UIResponder *)nextResponder {
    if (overrideNextResponder != nil)
        return overrideNextResponder;
    else
        return [super nextResponder];
}

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
    if (overrideNextResponder != nil)
        return NO;
    else
        return [super canPerformAction:action withSender:sender];
}

@end

然后,在您的手势操作处理程序中,检查文本视图是否已经是第一个响应者.如果是这样,让它覆盖下一个响应者; 否则键盘可能是隐藏的,你可以简单地becomeFirstResponder.当菜单隐藏时,您还必须重置覆盖:

if ([inputView isFirstResponder]) {
    inputView.overrideNextResponder = self;
    [[NSNotificationCenter defaultCenter] addObserver:self
        selector:@selector(menuDidHide:)
        name:UIMenuControllerDidHideMenuNotification object:nil];
} else {
    [self becomeFirstResponder];
}

- (void)menuDidHide:(NSNotification*)notification {

    inputView.overrideNextResponder = nil;
    [[NSNotificationCenter defaultCenter] removeObserver:self
        name:UIMenuControllerDidHideMenuNotification object:nil];
}

使用iOS 5中引入的表视图委托方法(shouldShowMenuForRowAtIndexPath等)对我来说不是一个解决方案,因为我需要控制菜单的位置(默认情况下,它只是在单元格上水平居中,但我显示的是消息气泡和希望菜单以实际气泡为中心).

Answer 2

在iOS 5中,您现在可以使用表视图委托方法来显示菜单控制器:

- (BOOL) tableView:(UITableView *)tableView shouldShowMenuForRowAtIndexPath:(NSIndexPath *)indexPath

- (BOOL)tableView:(UITableView *)tableView canPerformAction:(SEL)action forRowAtIndexPath:(NSIndexPath *)indexPath withSender:(id)sender;

- (void)tableView:(UITableView *)tableView performAction:(SEL)action forRowAtIndexPath:(NSIndexPath *)indexPath withSender:(id)sender;

以这种方式显示菜单控制器不会使键盘重新签名.

我仍然对此感到好奇,因为我有一个支持iOS 5之前的应用程序,我也想做你所说的(当出现复制菜单时不要退出键盘).