当用户多次加载视图时,在uitableview上保存附件复选标记

Question

所以我实现了一个带有tableview的UIViewController,基本上它作为我的uicollectionview的一组"过滤器"加载.

现在,当我点击我的tableview中的复选标记时,它会相应地"过滤"我的单元格,但现在当我再次重新加载视图时,我想显示我使用过的最新"复选标记"或"过滤器".

我已经看到这是用NSUserDefaults实现的,但是我无法成功实现它.

如果有人能帮助我,我将不胜感激.

码

FiltersViewController.m:

#import "FiltersViewController.h"

@interface FiltersViewController ()

@property (nonatomic, strong) NSMutableSet *selectedRowObjects;
//@property (nonatomic, strong) NSArray *filters;

@end

@implementation FiltersViewController


- (void)viewDidLoad
{
    [super viewDidLoad];

    self.selectedRowObjects = [NSMutableSet setWithCapacity:10];
}

- (IBAction)filtersSelected:(id)sender {
    [self.delegate filtersSelected:self.selectedRowObjects];
}

- (IBAction)cancelFilterSelection:(id)sender {
    [self.delegate filterSelectionCancelled];
}

- (NSString *)getKeyForIndex:(int)index
{
    return [NSString stringWithFormat:@"KEY%d",index];
}

- (BOOL) getCheckedForIndex:(int)index
{
    if([[[NSUserDefaults standardUserDefaults] valueForKey:[self getKeyForIndex:index]] boolValue]==YES)
    {
        return YES;
    }
    else
    {
        return NO;
    }
}

- (void) checkedCellAtIndex:(int)index
{
    BOOL boolChecked = [self getCheckedForIndex:index];

    [[NSUserDefaults standardUserDefaults] setValue:[NSNumber numberWithBool:!boolChecked] forKey:[self getKeyForIndex:index]];
    [[NSUserDefaults standardUserDefaults] synchronize];
}


#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return 10;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"filter" forIndexPath:indexPath];
    cell.textLabel.text = [NSString stringWithFormat:@"%u", indexPath.row];



    return cell;
}

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


    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    NSString *obj = cell.textLabel.text;

    if (cell.accessoryType == UITableViewCellAccessoryCheckmark) {
        cell.accessoryType = UITableViewCellAccessoryNone;
        [self.selectedRowObjects removeObject:obj];
    }
    else {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        [self.selectedRowObjects addObject:obj];
    }

    [tableView deselectRowAtIndexPath:indexPath animated:YES];

}
@end

Answer 1

您还需要检查 cellForRowAtIndexPath。把这段代码写在这个

if([[NSUserDefaults standardUserDefaults] objectForKey:[self getKeyForIndex:indexPath.row]])
{
    cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else
{
    cell.accessoryType = UITableViewCellAccessoryNone;
}

是的，不要忘记在 didSelectRowAtIndexPath 中调用此方法

[self checkedCellAtIndex:indexPath.row];

享受。

Answer 2

你几乎做对了所有事情。您只需将用于读取 NSUserDefault 值（针对选中的框）的逻辑放入cellForRowAtIndexPath委托方法中。这是当 UITableViewCells 显示在屏幕上时绘制 UITableViewCells 的方法。像这样的东西：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"filter" forIndexPath:indexPath];
    cell.textLabel.text = [NSString stringWithFormat:@"%u", indexPath.row];

    if ([self getCheckedForIndex:indexPath.row])
    {
        //code to set checkbox
    }

    return cell;
}