ios-表视图－demo3-单选

#import "RootViewController.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)loadView
{
    UIView *view = [[UIView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
    self.view = view;
    [view release];
    
    _listArray = [[UIFont familyNames] retain];
    
    _tableView = [[UITableView alloc] initWithFrame:view.bounds style:UITableViewStylePlain];
    _tableView.dataSource = self; // 设置数据源
    _tableView.delegate   = self; // 设置委托
    [self.view addSubview:_tableView];
    
    _index = -1;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - TableView Datasource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
{
    return [_listArray count];
} // section 中包含row的数量

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    // 定义一个静态标识符
    static NSString *cellIdentifier = @"cell";
    // 检查是否限制单元格
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    // 创建单元格
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] autorelease];
    }
    // 给cell内容赋值
    NSString *fontName = _listArray[indexPath.row];
    cell.textLabel.text = fontName;
    cell.textLabel.font = [UIFont fontWithName:fontName size:18];
    
    if (_index == indexPath.row) {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    }else {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }
    
    return cell;
    
} // 创建单元格

/*
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    
} // 表视图当中存在secion的个数，默认是1个
 */

/* question
 * 1、单选
 * 2、重用
 */

#pragma mark - UITableViewDelegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    //  NSIndexPath -> max row  取消上一次选中
    NSIndexPath *lastIndex = [NSIndexPath indexPathForRow:_index inSection:0];
    UITableViewCell *lastCell = [tableView cellForRowAtIndexPath:lastIndex];
    lastCell.accessoryType = UITableViewCellAccessoryNone;
    // 用户选中了新的一行
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    cell.accessoryType = UITableViewCellAccessoryCheckmark;
    _index = indexPath.row;

    [_tableView performSelector:@selector(deselectRowAtIndexPath:animated:) withObject:indexPath afterDelay:.5];
}

- (void)dealloc
{
    [_tableView release];
    _tableView = nil;
    [super dealloc];
}

@end

 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
    // 不加此句时，在二级栏目点击返回时，此行会由选中状态慢慢变成非选中状态。
    // 加上此句，返回时直接就是非选中状态。
}