美团HD(7)-添加取消搜索按钮

DJSelectCityViewController.m

#pragma mark - UISearchBar 代理方法

/** SearchBar开始编辑 */
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar {

    // 隐藏导航栏
    [self.navigationController setNavigationBarHidden:YES animated:YES];
    // 显示遮罩
    UIView *cover = [[UIView alloc] init];
    cover.backgroundColor = [UIColor blackColor];
    cover.alpha = 0.2;
    cover.frame = self.cityTableView.frame;
    cover.tag = DJCoverTag;
    
    // 由于UIView 不是UIControl,所以没有addTarget方法，可以使用UITapGestureRecognizer代替
    // 当conver被点击时，移除第一响应者
    [cover addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:searchBar action:@selector(resignFirstResponder)]];
    [self.view addSubview:cover];
    // 设置当前搜索框背景为高亮背景
    [searchBar setBackgroundImage:[UIImage imageNamed:@"bg_login_textfield_hl"]];
    // 显示取消按钮
    [searchBar setShowsCancelButton:YES animated:YES];
    
}



/** SearchBar结束编辑 */
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar {

    // 显示导航栏
    [self.navigationController setNavigationBarHidden:NO animated:YES];
    // 隐藏遮罩
    [[self.view viewWithTag:DJCoverTag] removeFromSuperview];
    // 设置当前搜索框背景为普通背景
    [searchBar setBackgroundImage:[UIImage imageNamed:@"bg_login_textfield"]];
    // 隐藏取消按钮
    [searchBar setShowsCancelButton:NO animated:YES];
    
}


/** 当searchBar上面的取消按钮被点击时调用此方法 */
- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar {
    // 隐藏键盘
    [searchBar resignFirstResponder];
    // 清空输入内容
    searchBar.text = @"";
}


/** 当searchBar内的文字发生改变时调用此方法 */
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {

    UIView *cover = [self.view viewWithTag:DJCoverTag];
    if (searchText.length) { // 当前输入内容不为空
        if(cover.subviews.count <= 0) {
            cover.alpha = 1.0;
            self.searchResultVC.view.frame = CGRectMake(0, 0, cover.width, cover.height);
            [cover addSubview:self.searchResultVC.view];
        }
    } else { // 当前输入内容为空
        [self.searchResultVC.view removeFromSuperview];
         cover.alpha = 0.2;
    }
    
}