通过加载 NSUserDefaults 检查多行

Posted 2023-03-12

【中文标题】通过加载 NSUserDefaults 检查多行

【英文标题】：Checkmark multiple rows by loading NSUserDefaults

【发布时间】：2017-03-14 13:14:30

【问题描述】：

我要求用户在 UITableView 中选择选项，然后将选择保存在 NSUserDefaults 中。我确保如果用户选择一个选项两次，它只会被添加一次......即没有重复。

我正在加载NSUserDefaults，然后尝试将行显示为“已选中”..以便用户记住他/她在之前运行应用程序时选择的内容。

现在，我知道只有cellForRowAtIndexPath 方法可以设置复选标记。 下面的代码只勾选最后一个对象。但是如何获得多个复选标记？

这就是我已经走了多远。

- (void)viewDidLoad 
[super viewDidLoad];
appSettings = [NSUserDefaults standardUserDefaults];
self.title = @"Select News Categories";
_selectedCategoriesArray = [[NSMutableArray alloc] init];
[self initNewsCategories];
[self loadNewsSelectedCategories];

#pragma mark UITableViewDataSource methods

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 

return 1;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 

return [_newsCategoriesArray count];



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cellNewsCategory" forIndexPath:indexPath];

// Configure the cell...
cell.textLabel.text = [NSString stringWithFormat:@"%@",[_newsCategoriesArray objectAtIndex:indexPath.row]];
NSString * cellText = [[cell textLabel] text];
for (NSString * lbl in _selectedNewsCategories)

    if ([cellText isEqualToString:lbl])
    
        [cell setAccessoryType:UITableViewCellAccessoryCheckmark];
    
    else
    
        [cell setAccessoryType:UITableViewCellAccessoryNone];
    


return cell;

#pragma mark UITableViewDelegate methods
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

[tableView deselectRowAtIndexPath:indexPath animated:YES];
UITableViewCell * selectedCell = [tableView cellForRowAtIndexPath:indexPath];
NSString * selectedCategory = [[selectedCell textLabel] text];
if ([tableView cellForRowAtIndexPath:indexPath].accessoryType == UITableViewCellAccessoryNone)

    [[tableView cellForRowAtIndexPath:indexPath] setAccessoryType:UITableViewCellAccessoryCheckmark];
    NSLog(@"%@", selectedCategory);
    [_selectedCategoriesArray addObject:selectedCategory];
    NSLog(@"_selectedCategoriesArray:%@", _selectedCategoriesArray);
    [appSettings setObject:_selectedCategoriesArray forKey:@"selectedNewsCategories"];


else if ([tableView cellForRowAtIndexPath:indexPath].accessoryType == UITableViewCellAccessoryCheckmark)

    [[tableView cellForRowAtIndexPath:indexPath] setAccessoryType:UITableViewCellAccessoryNone];
    NSLog(@"%@", selectedCategory);
    [_selectedCategoriesArray removeObject:selectedCategory];
    NSLog(@"_selectedCategoriesArray:%@", _selectedCategoriesArray);
    [appSettings setObject:_selectedCategoriesArray forKey:@"selectedNewsCategories"];

else

    [[tableView cellForRowAtIndexPath:indexPath] setAccessoryType:UITableViewCellAccessoryNone];

[appSettings synchronize];

#pragma mark Helper methods
-(void) initNewsCategories

_newsCategoriesArray = [NSArray arrayWithObjects:@"Arts",@"Business",@"Company",
                        @"Entertainment",@"Environment",@"Health",@"Lifestyle",
                        @"Media",@"Money",@"Most Read",@"Trending",@"World",nil];

-(void) loadNewsSelectedCategories

_selectedNewsCategories = [[NSMutableArray alloc] init];
_selectedNewsCategories = [appSettings objectForKey:@"selectedNewsCategories"];

【问题讨论】：

你的表格是否允许多选

【参考方案1】：

这段代码有问题：

for (NSString * lbl in _selectedNewsCategories)

    if ([cellText isEqualToString:lbl])
    
        [cell setAccessoryType:UITableViewCellAccessoryCheckmark];
    
    else
    
        [cell setAccessoryType:UITableViewCellAccessoryNone];
    

您首先选中单元格，然后继续搜索并取消标记单元格。 你需要使用这个：

for (NSString * lbl in _selectedNewsCategories)

    if ([cellText isEqualToString:lbl])
    
        [cell setAccessoryType:UITableViewCellAccessoryCheckmark];
        break;
    
    else
    
        [cell setAccessoryType:UITableViewCellAccessoryNone];
    

或者这个

if([_selectedNewsCategories indexOfObject: cellText] != NSNotFound)

  [cell setAccessoryType:UITableViewCellAccessoryCheckmark];
else

  [cell setAccessoryType:UITableViewCellAccessoryNone];