从 DetailView 将单元格添加到“收藏夹”TableView
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【中文标题】从 DetailView 将单元格添加到“收藏夹”TableView【英文标题】:Add Cell to "Favorites" TableView from DetailView 【发布时间】:2013-08-03 23:35:30 【问题描述】:我有一个现有的 UITableView,其中列出了该地区的许多咖啡馆。每个咖啡馆的数据都是从 mysql 数据库中提取的。当用户点击咖啡馆(单元格)时,它会将用户带到详细视图。目前,用户可以通过单击每个单元格中的星形图像来“收藏”一家咖啡馆(这会将收藏的单元格添加到收藏夹表视图中)。但是,我希望用户也能够从 DetailView 将咖啡馆添加到 FavoritesTableView(换句话说,从 DetailView “收藏”咖啡馆)。有谁知道我将如何实现这个?
现在,我的 DetailView.m(咖啡馆详情)中有星形按钮:
- (IBAction)buttonpressed:(UIButton *)fave
if (!checked)
[checkedButton setImage:[UIImage imageNamed:@"checked.png"] forState:UIControlStateNormal];
checked = YES;
else if (checked)
[checkedButton setImage:[UIImage imageNamed:@"unchecked.png"] forState:UIControlStateNormal];
checked = NO;
ViewController.m(咖啡桌视图)
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
static NSString *strainTableIdentifier = @"StrainTableCell";
StrainTableCell *cell = (StrainTableCell *)[tableView dequeueReusableCellWithIdentifier:strainTableIdentifier];
if (cell == nil)
cell = [[StrainTableCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:strainTableIdentifier];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
cell.selectionStyle = UITableViewCellSelectionStyleBlue;
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"StrainTableCell" owner:self options:nil];
cell = [nib objectAtIndex:0];
if (tableView == self.searchDisplayController.searchResultsTableView)
NSLog(@"Using the search results");
cell.titleLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Title"];
cell.descriptionLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Description"];
cell.ratingLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Rating"];
cell.ailmentLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Ailment"];
cell.actionLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Action"];
cell.ingestLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Ingestion"];
NSLog(@"%@", searchResults);
else
NSLog(@"Using the FULL LIST!!");
cell.titleLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Title"];
cell.descriptionLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Description"];
cell.ratingLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Rating"];
cell.ailmentLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Ailment"];
cell.actionLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Action"];
cell.ingestLabel.text = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Ingestion"];
NSMutableDictionary *item = [Strains objectAtIndex:indexPath.row];
cell.textLabel.text = [item objectForKey:@"text"];
[item setObject:cell forKey:@"StrainTableCell"];
BOOL checked = [[item objectForKey:@"checked"] boolValue];
NSLog(@"%i",checked);
UIImage *image = (checked) ? [UIImage imageNamed:@"checked.png"] : [UIImage imageNamed:@"unchecked.png"];
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
CGRect frame = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
button.frame = frame;
[button setBackgroundImage:image forState:UIControlStateNormal];
[button addTarget:self action:@selector(checkButtonTapped:event:) forControlEvents:UIControlEventTouchUpInside];
button.backgroundColor = [UIColor clearColor];
cell.accessoryView = button;
return cell;
- (void)checkButtonTapped:(id)sender event:(id)event
NSLog(@"made it here and event is %@",event);
NSSet *touches = [event allTouches];
UITouch *touch = [touches anyObject];
CGPoint currentTouchPosition = [touch locationInView:self.StrainTableView];
NSIndexPath * indexPath ;
indexPath = [self.StrainTableView indexPathForRowAtPoint: currentTouchPosition];
NSLog(@"indexpath is below");
NSLog(@"%@",indexPath);
if (indexPath != Nil)
NSMutableDictionary *item = [Strains objectAtIndex:indexPath.row];
BOOL isItChecked = [[item objectForKey:@"checked"] boolValue];
NSMutableArray *quickArray = [[NSMutableArray alloc] initWithArray:Strains];
[quickArray replaceObjectAtIndex:indexPath.row withObject:item];
[item setObject:[NSNumber numberWithBool:!isItChecked] forKey:@"checked"];
Strains = [quickArray copy];
[StrainTableView reloadData];
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
StrainDetailViewController *detailViewController = [[StrainDetailViewController alloc] initWithNibName:@"StrainDetailViewController" bundle:nil]; if ([searchResults count])
detailViewController.title = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Title"];
detailViewController.strainDetail = [searchResults objectAtIndex:indexPath.row];
else
detailViewController.title = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Title"];
detailViewController.strainDetail = [Strains objectAtIndex:indexPath.row];
NSLog(@"%@", Strains);
[self.navigationController pushViewController:detailViewController animated:YES];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
- (void)viewWillAppear:(BOOL)animated
[super viewWillAppear:animated];
if ([[NSUserDefaults standardUserDefaults] objectForKey:@"strains"] != Nil)
NSData *dataSave = [[NSUserDefaults standardUserDefaults] objectForKey:@"strains"];
Strains = [NSKeyedUnarchiver unarchiveObjectWithData:dataSave];
if (favoritesArray == Nil)
favoritesArray = [[NSMutableSet alloc] init];
if ([[NSUserDefaults standardUserDefaults] objectForKey:@"favorites"] != Nil)
NSData *dataSave = [[NSUserDefaults standardUserDefaults] objectForKey:@"favorites"];
favoritesArray = [NSKeyedUnarchiver unarchiveObjectWithData:dataSave];
我只是不确定我会添加什么样的代码以使“已检查”按钮将选定的单元格从 UITableView 添加到收藏夹表视图。
希望这是有道理的。有什么想法吗?
【问题讨论】:
当您导航到详细信息视图时,您的表视图是否会被释放,或者您的详细信息视图是否被推送到表视图顶部?您的表格视图中的咖啡馆列表是否有最喜欢的标志(或类似标志)? 嗨杰夫!详细信息视图被推送到表格视图的顶部(我相信)。是的,咖啡馆列表目前有一个最喜欢的标志(一颗星)。我已经更新了上面的代码,这样您就可以看到现有的“收藏夹”功能是如何工作的。为代码过载道歉。 【参考方案1】:从可维护性的角度来看,我通常采用的方法可能不是最好的。但是,从实现的角度来看,这非常容易。我将对我的对象(在您的情况下,选择的表视图的对象)的引用传递给详细信息视图。从详细信息视图中,我可以通过切换标志来更新该对象。由于该对象与表格视图是同一个对象,因此更新它也会更新表格视图(您可能必须重新绘制表格视图单元格)。最后,我从详细信息视图更新数据库。
编辑
所以在你的代码中,它看起来像这样。
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
StrainDetailViewController *detailViewController = [[StrainDetailViewController alloc] initWithNibName:@"StrainDetailViewController" bundle:nil]; if ([searchResults count])
detailViewController.title = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Title"];
//YOU'RE ALREADY DOING IT :)
detailViewController.strainDetail = [searchResults objectAtIndex:indexPath.row];
else
detailViewController.title = [[Strains objectAtIndex:indexPath.row] objectForKey:@"Title"];
//YOU'RE ALREADY DOING IT :)
detailViewController.strainDetail = [Strains objectAtIndex:indexPath.row];
NSLog(@"%@", Strains);
[self.navigationController pushViewController:detailViewController animated:YES];
您已经发送了对详细信息视图的引用!这使事情变得容易。在您的详细信息视图中,每当有人喜欢某个菌株时,请为该 strainDetail 对象设置最喜欢的标志。这也将更新 table view 中的 strainDetail 对象。它的工作原理是这样的,因为您将引用(也称为指针)传递给详细视图。换句话说,您的两个 strainDetail 对象都不是对象,而是指向内存地址的指针。如果您更新任一应变详细信息,则这两个应变详细信息的内存地址都会更改。不是 strainDetail 指针本身。这是进一步解释的链接https://softwareengineering.stackexchange.com/questions/17898/whats-a-nice-explanation-for-pointers
所以您的详细信息视图处理程序将如下所示
- (IBAction)buttonpressed:(UIButton *)fave
if (!checked)
[checkedButton setImage:[UIImage imageNamed:@"checked.png"] forState:UIControlStateNormal];
checked = YES;
else if (checked)
[checkedButton setImage:[UIImage imageNamed:@"unchecked.png"] forState:UIControlStateNormal];
checked = NO;
//updates in both the detail view and the table view
BOOL isItChecked = [[self.strainDetail objectForKey:@"checked"] boolValue];
[self.strainDetail setObject:[NSNumber numberWithBool:checked] forKey:@"checked"];
我还建议创建一个应变类来保存所有应变数据。使用字典并不好玩,容易出错,而且要花很长时间才能弄清楚您需要什么键。
【讨论】:
好的,请原谅我的无知(我还在学习/掌握术语,哈哈),但是这在我的代码中会是什么样子?帮助:) 我更新了我的帖子。另外,我认为当您的表格视图发生变化时,您不需要替换整个对象和数组。您应该能够修改对象而不需要所有其他东西。【参考方案2】:您可以将“最喜欢的”状态保存在全局变量/单例中,并在需要时检索它。
这样,即使您的表格视图被释放,您也不会丢失其单元格的状态。
【讨论】:
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