把背景的灰色改成透明色

   [[[[self.searchBar.subviews objectAtIndex:0]subviews]objectAtIndex:0]removeFromSuperview];
    [self.searchBar setBackgroundColor:[UIColor clearColor]];



    // 方法二
    [searchBar setBackgroundImage:[[UIImage alloc]init]];

当searchBar进入编辑状态时显示取消的按钮，当非编辑状态时不显示取消按钮

-(void)SearchBarBase
{
    self.searchBar=[[UISearchBar alloc]init];
    self.searchBar.delegate=self;
    self.searchBar.placeholder=@"搜素你的小区或大厦、街道名称";
    
    [self.view addSubview:self.searchBar];
    __weak typeof(self)weakself=self;
    [self.searchBar mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(weakself.view.mas_top).with.mas_offset(64);
        make.left.equalTo(weakself.view.mas_left);
        make.right.equalTo(weakself.view.mas_right);
        make.height.equalTo(@(44*HeigheScale));
    }];
    
    UIView *searchBarBackView =[[UIView alloc]init];
    searchBarBackView.backgroundColor =[UIColor colorWithRed:245/255.0 green:245/255.0 blue:245/255.0 alpha:1];
    [self.searchBar insertSubview:searchBarBackView atIndex:1];
    
    [searchBarBackView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(weakself.searchBar.mas_top);
        make.left.equalTo(weakself.searchBar.mas_left);
        make.right.equalTo(weakself.searchBar.mas_right);
        make.bottom.equalTo(weakself.searchBar.mas_bottom);

    }];
   
}


-(BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar
{
    [searchBar setShowsCancelButton:YES animated:YES];
    for (UIView *v in searchBar.subviews)
    {
        if ([v isKindOfClass:[UIButton class]])
        {
            UIButton *btn = (UIButton *)v;
            [btn setTitle:@"取消" forState:UIControlStateNormal];
            [btn setTitleColor:[UIColor darkGrayColor] forState:0];
        }
    }

    
    return  YES;
}

-(void)searchBarCancelButtonClicked:(UISearchBar *)searchBar
{
    [searchBar setShowsCancelButton:NO animated:YES];
    
    //取消成为第一响应者
    [self.searchBar resignFirstResponder];
    
}
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar
{
    [searchBar setShowsCancelButton:NO animated:YES];

}

遍历searchBar的子控件，这样就可以操作你想要的自视图了

for(id subView in [self.searchBar subviews]){
if([subView isKindOfClass:[UIButton class]]){
UIButton btn = (UIButton )subView;
[btn setTitle:@"取消" forState:UIControlStateNormal];
}
}