如何在objective c中实现一个全选/全选的按钮，而在上面的tableview？

// 在视图控制器中定义全选按钮和数据源数组
@interface YourViewController ()
@property (nonatomic, strong) UIButton *selectAllButton;
@property (nonatomic, strong) NSMutableArray *selectionArray;
@end

@implementation YourViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 创建全选按钮
    self.selectAllButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [self.selectAllButton setTitle:@"全选" forState:UIControlStateNormal];
    [self.selectAllButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [self.selectAllButton addTarget:self action:@selector(selectAllButtonTapped:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.selectAllButton];
    
    // 初始化数据源数组
    self.selectionArray = [NSMutableArray arrayWithCapacity:yourNumberOfRows];
    for (int i = 0; i < yourNumberOfRows; i++) {
        [self.selectionArray addObject:@NO]; // 初始状态为未选中
    }
}

- (void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];
    
    // 设置全选按钮的位置
    self.selectAllButton.frame = CGRectMake(0, 0, self.view.bounds.size.width, 50);
}

- (void)selectAllButtonTapped:(UIButton *)sender {
    // 全选按钮点击事件
    BOOL selectAll = !sender.selected;
    sender.selected = selectAll;
    
    // 更新数据源数组的值为全选按钮的选中状态
    for (int i = 0; i < self.selectionArray.count; i++) {
        self.selectionArray[i] = @(selectAll);
    }
    
    // 刷新TableView以更新所有cell的选中状态
    [self.tableView reloadData];
}

#pragma mark - UITableViewDataSource

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return yourNumberOfRows;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CellIdentifier" forIndexPath:indexPath];
    
    // 根据数据源数组中对应位置的值，设置cell的选中状态
    BOOL selected = [self.selectionArray[indexPath.row] boolValue];
    cell.accessoryType = selected ? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
    
    return cell;
}

#pragma mark - UITableViewDelegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    // 点击cell时更新数据源数组的对应位置的值，并刷新cell的选中状态
    BOOL selected = [self.selectionArray[indexPath.row] boolValue];
    self.selectionArray[indexPath.row] = @(!selected);
    [tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationNone];
}

@end