iOS UISearchBar用法

//UISearchBar的初始化
 _searchBar = [[UISearchBar alloc]initWithFrame:CGRectMake(40, 26, BESCREEN_W-45, 30)];
    _searchBar.delegate = self;
    _searchBar.placeholder = @"搜索学校名称";
    //修改searchBar搜索框的背景颜色
    UIImageView *barImageView = [[[_searchBar.subviews firstObject] subviews] firstObject];
    barImageView.image = BEIMAGENAME(@"状态栏+导航栏");
    //修改searchBar搜索的小图标
    [_searchBar setImage:[UIImage imageNamed:@"圆角矩形-659"] forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
    [self.bgImageView addSubview:_searchBar];

#pragma mark - 搜索栏代理
- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar{
    //修改cancel按钮
    [UIView animateWithDuration:0.1 animations:^{
    } completion:^(BOOL finished) {
        self.searchBar.frame = CGRectMake(8, 26, BESCREEN_W-8, 30);
        UIImageView *barImageView = [[[_searchBar.subviews firstObject] subviews] firstObject];
        barImageView.image = BEIMAGENAME(@"状态栏+导航栏");
        self.searchBar.showsCancelButton = YES;
        [self.view addSubview:self.grayView];
        for(UIView *view in  [[[self.searchBar subviews] objectAtIndex:0] subviews]) {
            if([view isKindOfClass:[NSClassFromString(@"UINavigationButton") class]]) {
                UIButton * cancel =(UIButton *)view;
                [cancel setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
                [cancel setTitle:@"取消" forState:UIControlStateNormal];
                cancel.titleLabel.font = FontSet(13);
            }
        }
            //修改输入框的字体大小和颜色
        for (UIView* subview in [[searchBar.subviews lastObject] subviews]) {
            if ([subview isKindOfClass:[UITextField class]]) {
                UITextField *textField = (UITextField*)subview;
                textField.textColor = TITLE_COLOR;                         //修改输入字体的颜色
                textField.font = FontSet(13);
                [textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
                [textField setValue:[UIFont boldSystemFontOfSize:13] forKeyPath:@"_placeholderLabel.font"];
                [textField setValue:BECOLOR(176, 176, 176, 1) forKeyPath:@"_placeholderLabel.textColor"];   //修改placeholder的颜色
            }
        }

    }];
    return YES;
}

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
    if (searchText.length>0) {

        self.isSearch = YES;
        [self.grayView removeFromSuperview];
        self.grayView = nil;
        NSPredicate *searchPredicate = [NSPredicate predicateWithFormat:@"SELF CONTAINS[c] %@", self.searchBar.text];
        self.filterArray = [[self.nameArray filteredArrayUsingPredicate:searchPredicate] mutableCopy];
        if (self.filterArray.count==0) {
            self.tableView.hidden = YES;
            [self.view addSubview:self.tipLabel];
        }else{
            self.tableView.hidden = NO;
            [self.tipLabel removeFromSuperview];
            self.tipLabel=nil;
        }
    }else{
        self.isSearch = YES;
        [self.tipLabel removeFromSuperview];
        self.tipLabel=nil;
        [self.view addSubview:self.grayView];
    }
    [self.tableView reloadData];

}

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar{
    [UIView animateWithDuration:0.1 animations:^{
    } completion:^(BOOL finished) {
        _searchBar.frame = CGRectMake(40, 26, BESCREEN_W-45, 30);
        UIImageView *barImageView = [[[_searchBar.subviews firstObject] subviews] firstObject];
        barImageView.image = BEIMAGENAME(@"状态栏+导航栏");
        self.searchBar.showsCancelButton = NO;
    }];
    self.isSearch = NO;
    [self.grayView removeFromSuperview];
    [self.tipLabel removeFromSuperview];
    self.tableView.hidden = NO;
    self.searchBar.text = @"";
    [self.tableView reloadData];
    [self.searchBar resignFirstResponder];
}


- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar{
    [self.searchBar resignFirstResponder];
}