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我已閱讀每篇文章並多次嘗試所有解決方案，但無法獲得正確的功能。保存，保留和檢索數組中的選定單元格
我有一個來自本地JSON文件的數據的tableview。我需要的用戶能夠：
- 選擇多個單元格
- 顯示覆選標記上選定單元格
- 寫那些選擇到一個數組
- 刪除選擇時選中
5.當用戶切換查看或離開並返回到tableview，關閉並重新打開應用程序等時，用選中標記保存/保留選項。
我已經設法得到1-4的工作，但我被困在＃5，無法想象出我的生活。我儘可能地嘗試了NSUserDefaults。任何幫助表示讚賞。以下是當前的代碼。
此外，爲什麼我不得不雙擊一個單元格取消選中它？
@interface FilterViewController() <UISearchResultsUpdating>
@property (nonatomic, strong) NSArray *IngredientsArray;
@property (nonatomic, strong) UISearchController *searchController;
@property (nonatomic, strong) NSMutableArray *searchResults;
@property (nonatomic, strong) NSMutableArray *selectedCell;
@property (nonatomic, strong) NSMutableArray *selectedIngredients;
//I added this property to keep track of the selected row
@property (strong,nonatomic) NSIndexPath *selectedPath;
@end
@implementation FilterViewController {
NSArray *_locations;
}
- (void)viewDidLoad {
[super viewDidLoad];
self.selectedIngredients = [NSMutableArray array];
self.selectedCell = [NSMutableArray array];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
self.lastIndexPath = [defaults objectForKey:@"lastIndexPathUsed"];
// Create a new JSONLoader with a local file URL
JSONLoaderIngreds *jsonLoader = [[JSONLoaderIngreds alloc] init];
NSURL *url = [[NSBundle mainBundle] URLForResource:@"locations" withExtension:@"json"];
// There's no transition in our storyboard to our search results tableview or navigation controller
// so we'll have to grab it using the instantiateViewControllerWithIdentifier: method
UINavigationController *searchResultsController = [[self storyboard] instantiateViewControllerWithIdentifier:@"FilterViewSearchResultsNavController"];
// Our instance of UISearchController will use searchResults
self.searchController = [[UISearchController alloc] initWithSearchResultsController:searchResultsController];
// The searchcontroller's searchResultsUpdater property will contain our tableView.
self.searchController.searchResultsUpdater = self;
// create the searchBar programatically.
self.searchController.searchBar.frame = CGRectMake(self.searchController.searchBar.frame.origin.x,
self.searchController.searchBar.frame.origin.y,
self.searchController.searchBar.frame.size.width, 44.0);
self.tableView.tableHeaderView = self.searchController.searchBar;
//Sets LocationsViewController as presenter for LocationDetailViewController after searxh results dsiplayed
//and selected.. Required so searchbar doesn't show in detailsview after segue, and instead, default nav
//controller back button displays.
self.definesPresentationContext = true;
// Load the data on a background queue...
// As we are using a local file it's not really necessary, but if we were connecting to an online URL then we'd need it
//NSString *ingreds = [dict objectForKey:@"ingredients"]
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
_locations = [jsonLoader ingredientsFromJSONFile:url];
// Now that we have the data, reload the table data on the main UI thread
[self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:YES];
});
}
// Just before showing the LocationViewController, set the selected Location object
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
LocationsViewController *vc = segue.destinationViewController;
NSIndexPath *indexPath = [self.tableView indexPathForCell:sender];
vc.location = [_locations objectAtIndex:indexPath.row];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)viewWillAppear:(BOOL)animated
{
//I added this if clause to select the row that was last selected
if (self.selectedPath != nil) {
[self.tableView selectRowAtIndexPath:self.selectedPath animated:NO scrollPosition:UITableViewScrollPositionNone];
}
}
#pragma mark - Table View Controller Methods
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
self.selectedPath = indexPath;
NSString *Ingredient = [_locations objectAtIndex:indexPath.row];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if([self isRowSelectedOnTableView:tableView atIndexPath:indexPath]){
[self.selectedCell removeObject:indexPath];
[self.selectedIngredients removeObject:Ingredient];
cell.accessoryType = UITableViewCellAccessoryNone;
} else {
[self.selectedCell addObject:indexPath];
[self.selectedIngredients addObject:Ingredient];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
NSLog(@"***************Selected Ingredients**************** %@", self.selectedIngredients);
NSUserDefaults *userdefaults = [NSUserDefaults standardUserDefaults];
[userdefaults setObject:[NSString stringWithFormat:@"%ld",(long)indexPath.section] forKey:@"lastIndexPathUsed"];
[userdefaults synchronize];
}
-(BOOL)isRowSelectedOnTableView:(UITableView *)tableView atIndexPath:(NSIndexPath *)indexPath
{
return ([self.selectedCell containsObject:indexPath]) ? YES : NO;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *unifiedID = @"FilterCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:unifiedID];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:unifiedID];
}
cell.textLabel.text = [_locations objectAtIndex:indexPath.row];
cell.imageView.image = [UIImage imageNamed:@"ingredientsicon3232.png"];
//if the indexPath was found among the selected ones, set the checkmark on the cell
cell.accessoryType = ([self isRowSelectedOnTableView:tableView atIndexPath:indexPath]) ? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
return cell;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [_locations count];
}
UPDATE：
我設法改變的代碼的建議使用下面的更新的代碼，以節省選擇以陣列NSUserDefaults，但我仍然無法弄清楚，以節省所需的cellForRowAtIndexPath代碼/記住檢查標記。
我該如何編碼cellForRowAtIndexPath來調用複選標記？
保存的選擇要與此代碼數組：
的viewDidLoad代碼：
_selections = [NSMutableArray arrayWithArray:(NSArray *)[[NSUserDefaults standardUserDefaults] objectForKey:@"selections"]];
if(_selections == nil){
_selections = [[NSMutableArray alloc] init];
}
didSelectRowAtIndexPath方法代碼：
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
{
if ([_selections containsObject: cell.textLabel.text] == NO){
[_selections addObject:cell.textLabel.text];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
} else {
[_selections removeObject:cell.textLabel.text];
cell.accessoryType = UITableViewCellAccessoryNone;
}
NSLog(@"***************Selected Ingredients**************** %@", _selections);
NSUserDefaults *userdefaults = [NSUserDefaults standardUserDefaults];
[userdefaults setObject:_selections forKey:@"selections"];
[userdefaults synchronize];
NSLog(@"-------------NSUserDefaults------------%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation])
}
我想我明白了，但是您能否展示如何在代碼中完成這項工作？我嘗試過幾種不同的方式，無法工作。仍在學習。謝謝。 – Jason
我正在旅行。可能在幾個小時內，我可以給你一個例子，但現在你應該嘗試這三個步驟，你會得到它。這並不困難。只要給它一個。 – Harsh
按照你的指示，我已經設法將選擇保存到用戶默認值存儲的數組中，但我無法弄清楚保留選中標記的代碼。你能提供代碼示例嗎？ – Jason