我在一个多星期前提交了应用,今天收到了可怕的拒绝邮件。它告诉我,我的应用程序不能被接受,因为我使用的是非公共API;具体来说,它说,

应用程序中包含的非公共API是firstResponder。

现在,违规的API调用实际上是一个解决方案,我发现这里的SO:

UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
UIView   *firstResponder = [keyWindow performSelector:@selector(firstResponder)];

如何在屏幕上显示当前的第一响应器?我正在寻找一种不会让我的应用程序被拒绝的方法。


当前回答

romeo https://stackoverflow.com/a/2799675/661022的解决方案很酷,但我注意到代码还需要一个循环。我在使用tableViewController。 我编辑了剧本,然后检查了一下。一切都很完美。

我建议你这样做:

- (void)findFirstResponder
{
    NSArray *subviews = [self.tableView subviews];
    for (id subv in subviews )
    {
        for (id cell in [subv subviews] ) {
            if ([cell isKindOfClass:[UITableViewCell class]])
            {
                UITableViewCell *aCell = cell;
                NSArray *cellContentViews = [[aCell contentView] subviews];
                for (id textField in cellContentViews)
                {
                    if ([textField isKindOfClass:[UITextField class]])
                    {
                        UITextField *theTextField = textField;
                        if ([theTextField isFirstResponder]) {
                            NSLog(@"current textField: %@", theTextField);
                            NSLog(@"current textFields's superview: %@", [theTextField superview]);
                        }
                    }
                }
            }
        }
    }
}

其他回答

下面是一个基于Jakob Egger最优秀的答案在Swift中实现的扩展:

import UIKit

extension UIResponder {
    // Swift 1.2 finally supports static vars!. If you use 1.1 see: 
    // http://stackoverflow.com/a/24924535/385979
    private weak static var _currentFirstResponder: UIResponder? = nil
    
    public class func currentFirstResponder() -> UIResponder? {
        UIResponder._currentFirstResponder = nil
        UIApplication.sharedApplication().sendAction("findFirstResponder:", to: nil, from: nil, forEvent: nil)
        return UIResponder._currentFirstResponder
    }
    
    internal func findFirstResponder(sender: AnyObject) {
        UIResponder._currentFirstResponder = self
    }
}

斯威夫特4

import UIKit    

extension UIResponder {
    private weak static var _currentFirstResponder: UIResponder? = nil
    
    public static var current: UIResponder? {
        UIResponder._currentFirstResponder = nil
        UIApplication.shared.sendAction(#selector(findFirstResponder(sender:)), to: nil, from: nil, for: nil)
        return UIResponder._currentFirstResponder
    }
    
    @objc internal func findFirstResponder(sender: AnyObject) {
        UIResponder._currentFirstResponder = self
    }
}

对于Swift 3和4版本的nevyn的回答:

UIApplication.shared.sendAction(#selector(UIView.resignFirstResponder), to: nil, from: nil, for: nil)

这是我在UIViewController类别中的东西。对很多事情都很有用,包括获取第一响应者。积木很棒!

- (UIView*) enumerateAllSubviewsOf: (UIView*) aView UsingBlock: (BOOL (^)( UIView* aView )) aBlock {

 for ( UIView* aSubView in aView.subviews ) {
  if( aBlock( aSubView )) {
   return aSubView;
  } else if( ! [ aSubView isKindOfClass: [ UIControl class ]] ){
   UIView* result = [ self enumerateAllSubviewsOf: aSubView UsingBlock: aBlock ];

   if( result != nil ) {
    return result;
   }
  }
 }    

 return nil;
}

- (UIView*) enumerateAllSubviewsUsingBlock: (BOOL (^)( UIView* aView )) aBlock {
 return [ self enumerateAllSubviewsOf: self.view UsingBlock: aBlock ];
}

- (UIView*) findFirstResponder {
 return [ self enumerateAllSubviewsUsingBlock:^BOOL(UIView *aView) {
  if( [ aView isFirstResponder ] ) {
   return YES;
  }

  return NO;
 }];
}

遍历可能是第一响应器的视图,并使用- (BOOL)isFirstResponder来确定它们当前是否是。

如果你的最终目标只是辞职第一个响应者,这应该工作:[self。视图endEditing:是的)