ios 最少代码实现 tableview 单行选中 及 默认选中

实现 tableView 中 cell 的单行选中

• 首先自己创建一个列表，实现单选，先定义一个变量记录每次点击的cell的indexPath:
• 先说下 tableView 默认选中行

// 默认选中行
    NSIndexPath *firstPath = [NSIndexPath indexPathForRow:selectRow inSection:0];
    [self.tableView selectRowAtIndexPath:firstPath animated:YES scrollPosition:UITableViewScrollPositionNone];
    if ([self.tableView.delegate respondsToSelector:@selector(tableView:didSelectRowAtIndexPath:)]) {
        [self.tableView.delegate tableView:self.tableView didSelectRowAtIndexPath:firstPath];
    }

• 1. 系统自带的选中效果

Snip20170315_2.png

• 实现代码

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *leftCell = @"ordeDetailCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:leftCell];
    if (!cell) {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:leftCell];
        cell.backgroundColor = [UIColor whiteColor];
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
    }
    cell.textLabel.text = [NSString stringWithFormat:@"%zd行%zd列", indexPath.section, indexPath.row];
    // 当上下拉动的时候，因为cell的复用性，我们需要重新判断一下哪一行是打钩的
    if (_selIndex == indexPath) {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    } else {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    //之前选中的，取消选择
    UITableViewCell *celled = [tableView cellForRowAtIndexPath:_selIndex];
    celled.accessoryType = UITableViewCellAccessoryNone;
    //记录当前选中的位置索引
    _selIndex = indexPath;
    //当前选择的打勾
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    cell.accessoryType = UITableViewCellAccessoryCheckmark;
    
    [tableView reloadData];
    NSLog(@"old : %zd行%zd列 new : %zd行%zd列", _selIndex.section, _selIndex.row, indexPath.section, indexPath.row);
}

• 2.自定义效果

Snip20170315_1.png

• 实现代码

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    // 创建 tableView
   ............
    
    UIImageView *ima = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"icon-successed"]];
    [ima sizeToFit];
    CGFloat width = ima.bounds.size.width;
    CGFloat height = ima.bounds.size.height;
    [cell.contentView addSubview:ima];
    [ima mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerY.equalTo(cell.contentView);
        make.right.equalTo(cell.contentView.right).offset(-2*SPCommonMargin);
        make.width.equalTo(width);
        make.height.equalTo(height);
    }];
    [self.imageArray addObject:ima];
    ima.hidden = YES;
    
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    
    NSLog(@"%zd个 = old : %zd行%zd列 new : %zd行%zd列", self.imageArray.count, _selIndex.section, _selIndex.row, indexPath.section, indexPath.row);
    
    if (self.imageArray.count > 0) {
        
        UIImageView *sender = self.imageArray[_selIndex.row];
        sender.hidden = YES;
        
        _selIndex = indexPath;
        
        UIImageView *newSender = self.imageArray[indexPath.row];
        newSender.hidden = NO;
    }
 }