IOS點擊searchBar時，取消背景變暗的效果

     最近項目想在點擊searchBar時，默認彈出搜索歷史，而不是背景變黑的dimming效果。在網上查找了幾種方法，發現最好用的還是在keyboard彈出和隱藏時將searchDisplayController中得dimmingView背景色設置爲透明。以下爲代碼:

1、首先在controller load的時候添加對彈出和隱藏鍵盤事件的監聽：

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow) name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow) name:UIKeyboardWillHideNotification object:nil];

2、實現keyboardWillShow函數：

- (void) keyboardWillShow

{

    for(UIView * v in searchDisplayController_.searchContentsController.view.subviews)

    {

        if([v isMemberOfClass:[UIControl class]])

        {

            v.backgroundColor = [UIColor clearColor];

        }

    }

}