UIScrollView 上如果有UITextField的話，結束編輯（退出鍵盤）直接用touchesBegan方法無效，需要再給UIScrollView加一個分類，重寫幾個方法。
網上已經有很多前輩給了相關代碼是這樣的（閱前提示：這樣是有問題的！）：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [[self nextResponder] touchesBegan:touches withEvent:event];
    [super touchesBegan:touches withEvent:event];
    
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [[self nextResponder] touchesMoved:touches withEvent:event];
    [super touchesMoved:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [[self nextResponder] touchesEnded:touches withEvent:event];
    [super touchesEnded:touches withEvent:event];
}

這樣會有一個嚴重問題，就是使用手寫輸入法輸入中文會導致崩潰（雖然使用手寫輸入法的人不多，但也不能無視他們）。被坑死，問題是百度出來尼瑪80~90%全是這種解決方法。坑死人！

有一些前輩對于“UIScrollView點擊空白處退出鍵盤”就提出了另一種解決方法：加一層view，給view一個點擊事件，退出鍵盤。

但是我的項目中已經被前一種方法坑了，已經有用戶反映手寫崩潰，換第二種方法的話很麻煩，需要修改之后重新提交審核，不能及時解決，我需要及時的用JSPatch線上打補丁解決。調試了很久，我發現手寫鍵盤在調用UIScrollView的這個分類的方法時，self的類型是UIKBCandidateCollectionView，一種系統沒有暴露出來的類型，應該是UIScrollView的一個子類，所以解決辦法就呼之欲出了，直接上代碼。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    if (![self isMemberOfClass:[UIScrollView class]]) {
        
    } else {
        [[self nextResponder] touchesBegan:touches withEvent:event];
        if ([super respondsToSelector:@selector(touchesBegan:withEvent:)]) {
            [super touchesBegan:touches withEvent:event];
        }
    }
    
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    if (![self isMemberOfClass:[UIScrollView class]]) {
        
    } else {
        [[self nextResponder] touchesMoved:touches withEvent:event];
        if ([super respondsToSelector:@selector(touchesBegan:withEvent:)]) {
            [super touchesMoved:touches withEvent:event];
        }
    }
    
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    if (![self isMemberOfClass:[UIScrollView class]]) {
        
    } else {
        [[self nextResponder] touchesEnded:touches withEvent:event];
        if ([super respondsToSelector:@selector(touchesBegan:withEvent:)]) {
            [super touchesEnded:touches withEvent:event];
        }
    }
}

手寫輸入法崩潰完美解決O(∩_∩)O~~