在iphone的UIWebView中显示选择的自定义菜单

Question

当用户在UIWebView上完成选择时,我想显示2个选项,如"hi"和"bye".

我已将观察者添加到我的视图控制器,如下所示.但我不知道进一步的实施.

[[UIMenuController sharedMenuController] addObserver:self 
                                          forKeyPath:UIMenuControllerWillShowMenuNotification
                                             options:nil
                                             context:nil
 ];

Answer 1

萨格尔,

你的问题已经有几个月了,但我终于想到了这个,所以我想我会回答它,以防它帮助别人.

我将以下代码添加到包含webview的视图控制器的viewDidAppear:方法中.

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];

    UIMenuItem *customMenuItem1 = [[[UIMenuItem alloc] initWithTitle:@"Custom 1" action:@selector(customAction1:)] autorelease];
    UIMenuItem *customMenuItem2 = [[[UIMenuItem alloc] initWithTitle:@"Custom 2" action:@selector(customAction2:)] autorelease];
    [[UIMenuController sharedMenuController] setMenuItems:[NSArray arrayWithObjects:customMenuItem1, customMenuItem2, nil]];
}

在我的viewDidDisappear:中,我继续删除这些项目:

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];

    [[UIMenuController sharedMenuController] setMenuItems:nil];
}

然后,我在视图控制器中实现了canPerformAction:withSender:方法.它有助于理解响应者和响应者链的概念,以了解这里发生了什么.基本上,你的uiviewcontroller是响应者链的一部分,所以它会被问到它是否可以处理响应者链上方的对象(如UIWebView)不知道如何处理的任何操作(比如上面添加的自定义操作)有关详细信息,请参阅UIResponder文档和iOS事件处理指南.

现在,当为webview调用canPerformAction:withSender:时,sender参数设置为nil.所以,我试着对我如何写这个函数有点聪明.基本上,我确保发件人是零,我向用户显示webview,页面上的任何其他控件都不是第一个响应者.如果是这种情况,那么我检查这是否是我在上面定义的操作之一,如果是,则返回YES.在所有其他情况下,我通过在super上调用相同的方法从UIViewController返回默认值.

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
    if (webView.superview != nil && ![urlTextField isFirstResponder]) {
        if (action == @selector(customAction1:) || action == @selector(customAction2:)) {
            return YES;
        }
    }

    return [super canPerformAction:action withSender:sender];
}

当然,现在下一步是弄清楚如何实际选择(可能是通过在webview中运行一些JavaScript).

Answer 2

迅速：

class ViewController: UIViewController {
    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)

        // add two custom menu items to the context menu of UIWebView (assuming in contenteditable mode)
        let menuItem1 = UIMenuItem(title: "Foo", action: #selector(ViewController.foo))
        let menuItem2 = UIMenuItem(title: "Bar", action: #selector(ViewController.bar))
        UIMenuController.sharedMenuController().menuItems = [menuItem1, menuItem2]
    }

    override func viewDidDisappear(animated: Bool) {
        super.viewDidAppear(animated)
        UIMenuController.sharedMenuController().menuItems = nil
    }

    override func canPerformAction(action: Selector, withSender sender: AnyObject?) -> Bool {
        if webView?.superview != nil {
            if action == #selector(ViewController.foo) || action == #selector(ViewController.bar) {
                return true
            }
        }

        return super.canPerformAction(action, withSender: sender)
    }

    func foo() {
        print("foo")
    }

    func bar() {
        print("bar")
    }
}

注意：#selector 在 Swift 2.2 中可用。