设置搜索框后面的取消按钮，字体，颜色。

 mySearchBar.tintColor= [UIColorwhiteColor];

   mySearchBar.barTintColor=kRedHuangColor;

   mySearchBar.backgroundImage= [UIImageimageWithColor:kRedHuangColorsize:CGSizeMake(kScreenWidth,40)];

    [mySearchBarbecomeFirstResponder];

    mySearchBar.hidden=NO;

 mySearchBar.showsCancelButton=YES;

    UIButton *cancelButton;

    UIView *topView = mySearchBar.subviews[0];

    for (UIView *subView in topView.subviews) {

       if([subViewisKindOfClass:NSClassFromString(@"UINavigationButton")]) {

            cancelButton = (UIButton *)subView;

        }

    }

    if (cancelButton) {

        [cancelButtonsetTitle:@"取消"forState:UIControlStateNormal];

        [cancelButtonsetTitleColor:[UIColorwhiteColor]forState:UIControlStateNormal];

        cancelButton.titleLabel.tintColor = [UIColor whiteColor];

    }