更改单元格的背景颜色

Posted 2023-02-27

【中文标题】更改单元格的背景颜色

【英文标题】：Change background colour of Cell

【发布时间】：2015-05-01 11:26:19

【问题描述】：

如果插入了新项目，是否可以更改表格单元格的背景颜色。我可以更改所有单元格的背景颜色，但我只是新添加的一个来更改颜色。

有什么办法可以做到吗？

- (void)insertNewObject:(OutgoingHolder*)expense 
    NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
    NSEntityDescription *entity = [[self.fetchedResultsController fetchRequest] entity];
    Outgoing *outgoing = [NSEntityDescription insertNewObjectForEntityForName:[entity name] inManagedObjectContext:context];

    // If appropriate, configure the new managed object.
    // Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the template.
    //[newManagedObject setValue:[NSDate date] forKey:@"timeStamp"];

    // Save the context.

    outgoing.costDescription = expense.costDescription;
    outgoing.amount = [NSNumber numberWithFloat:expense.amount];
    outgoing.date = expense.date;
    outgoing.category = expense.category;


    NSError *error = nil;
    if (![context save:&error]) 
        // Replace this implementation with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    

    //CHANGES HERE
    self.addedNewRow=0;
    [self.tableView reloadData];






#pragma mark - Table View

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
    return [[self.fetchedResultsController sections] count];


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
    id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];
    return [sectionInfo numberOfObjects];


-(NSString*) tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section

    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];

    return[sectionInfo name];




- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath


    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    [self configureCell:cell atIndexPath:indexPath];

    if (_total > 0.0 ) 
        //UPDATE 1:
        NSLog(@"%@",[@"Total : " stringByAppendingString:[NSString stringWithFormat:@"%.2f", self.total]]);
        id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][indexPath.section];
        if ([sectionInfo numberOfObjects]-1  == indexPath.row  && self.addedNewRow!=-1) 
            cell.contentView.backgroundColor = [UIColor orangeColor];
            [cell.textLabel setBackgroundColor:[UIColor clearColor]];
        
    


    return cell;


- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath 
    // Return NO if you do not want the specified item to be editable.
    return YES;


- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath 
    if (editingStyle == UITableViewCellEditingStyleDelete) 
        NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
        [context deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];

        NSError *error = nil;
        if (![context save:&error]) 
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        
    


- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath 
    Outgoing *outgoing = [self.fetchedResultsController objectAtIndexPath:indexPath];
    cell.textLabel.text = outgoing.costDescription;
    cell.detailTextLabel.text = [NSString stringWithFormat:@"%.2f",[outgoing.amount floatValue]];

【问题讨论】：

有什么你试过的，可以给我们看看吗？

您可以更改每个单元格的背景颜色，您不仅限于all。

贴出你尝试过的代码

如何添加新单元格？你也可以发布那个代码吗？

@ViralSavaj 请查看已编辑的代码问题

【参考方案1】：

你可以通过以下方式获取新添加的单元格，前提是新单元格始终添加在最后一个位置。

只需在 .h 文件中定义标志变量，例如

@property (nonatomic, assign) int addedNewRow;

现在在您的.m 文件中初始化addedNewRow 和-1 之类的，

- (void)viewDidLoad 
    [super viewDidLoad];
    self.addedNewRow=-1;
    //other stuff

替换下面两个对您的代码有一点增强的方法，

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath


    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    [self configureCell:cell atIndexPath:indexPath];

    //UPDATE 1:
    id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][indexPath.section];
    if ([sectionInfo numberOfObjects]-1  == indexPath.row  && self.addedNewRow!=-1) 
        cell.contentView.backgroundColor = [UIColor orangeColor];
        [cell.textLabel setBackgroundColor:[UIColor clearColor]];
    

    return cell;


- (IBAction)insertNewElement:(UIBarButtonItem *)sender

    NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
    NSEntityDescription *entity = [[self.fetchedResultsController fetchRequest] entity];
    Outgoing *outgoing = [NSEntityDescription insertNewObjectForEntityForName:[entity name] inManagedObjectContext:context];

    // If appropriate, configure the new managed object.
    // Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the template.
    //[newManagedObject setValue:[NSDate date] forKey:@"timeStamp"];

    // Save the context.

    outgoing.costDescription = expense.costDescription;
    outgoing.amount = [NSNumber numberWithFloat:expense.amount];
    outgoing.date = expense.date;
    outgoing.category = expense.category;


    NSError *error = nil;
    if (![context save:&error]) 
        // Replace this implementation with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    

    //CHANGES HERE
    self.addedNewRow=0;
    [self.tableView reloadData];

希望对你有帮助！！

【讨论】：

我收到关于 id sectionInfo = [self.fetchedResultsController section][section] 的错误；在 [部分]

@John，很好 'UPDATE 1:' 从已编辑的答案更新并替换下一行

这仍然突出显示所有单元格。当应用程序加载时，背景颜色不会出现，但是当我添加一个新项目时，所有单元格都会突出显示

我还有一个 if 语句来检查一个值是否大于另一个值。如果该值更大，那么我是否希望突出显示新单元格。其余的将保持不变。

我想要做的只是在我拥有的总数大于 0 时突出显示添加的新单元格。如果我添加一个新单元格，如果值仍然更大，则新突出显示的单元格应该保持突出显示.但是如果该值不大于则背景将是默认的

【参考方案2】：

试试这个，

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath

    if (indexPath.row % 2 == 0)
    
        cell.backgroundColor =[UIColor blueColor];
     else 
        cell.backgroundColor =[UIColor redColor];
    

【讨论】：

你确定这会工作，只有新添加的单元格？

【参考方案3】：

存储新插入的indexPath，并在willDisplayingCell:forRowAtIndexPath:委托方法中检查该indexPath，并更改单元格的contentView的背景颜色。

【参考方案4】：

使用tableView: willDisplayCell:方法改变颜色

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath 
    if (...) //do your stuff.
        [cell.backView setBckgroundColor:[UIColor redColor];
     else 
        [cell.backView setBckgroundColor:[UIColor whiteColor];
    

change the background color of customize tableViewCell

【参考方案5】：

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath

    cell.backgroundColor = [UIColor whiteColor];

    if (indexPath.row == dataArray.count-1)
    
        [cell setBackgroundColor:[UIColor colorWithRed:123/255.0 green:234.0/255.0 blue:255/225.0 alpha:1.0]];
    

【参考方案6】：

更新答案：

numberOfRowsInSection 方法：

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

    return [dataArray count];

在 cellForRowAtIndexPath 方法内：

if(indexPath.row == dataArray.count-1)
    cell.contentView.backgroundColor = [UIColor blueColor];

编辑 1：

dataArray 是用于填充表格行的数组，用于检查数组中元素的总数以在numberOfRowsInSection 方法中加载到表格中。

【讨论】：

dataArray 的用途是什么？

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath]; [self configureCell:cell atIndexPath:indexPath]; if(indexPath.row == dataArray.count-1) cell.contentView.backgroundColor = [UIColor blueColor]; 返回单元格；

dataArray 是用于馈送表格行的数组。

我对表格视图相当陌生，我在 dataArray 上收到一个错误，我不完全确定我的数组是什么。它会在哪里声明？

问题已更新！最好发布有问题的代码。

【参考方案7】：

您可以在cellForRowAtIndexPath 中为新添加的单元格应用验证。

在.h文件中声明一个变量。

Outgoing *lastOutgoing;

作为viewDidLoad 方法中的初始lastOutgoing = nil。一旦添加了新对象。在lastOutgoing 中保留该对象的引用。这里是insertNewObject修改的方法。

- (void)insertNewObject:(OutgoingHolder*)expense 
    NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
    NSEntityDescription *entity = [[self.fetchedResultsController fetchRequest] entity];
    Outgoing *outgoing = [NSEntityDescription insertNewObjectForEntityForName:[entity name] inManagedObjectContext:context];

    // If appropriate, configure the new managed object.
    // Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the template.
    //[newManagedObject setValue:[NSDate date] forKey:@"timeStamp"];

    // Save the context.

    outgoing.costDescription = expense.costDescription;
    outgoing.amount = [NSNumber numberWithFloat:expense.amount];
    outgoing.date = expense.date;
    outgoing.category = expense.category;


    NSError *error = nil;
    if (![context save:&error]) 
        // Replace this implementation with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    

  lastOutgoing = outgoing;
  [self.tableView reloadData];

在configureCell方法中

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath 
    Outgoing *outgoing = [self.fetchedResultsController objectAtIndexPath:indexPath];
    cell.textLabel.text = outgoing.costDescription;
    cell.detailTextLabel.text = [NSString stringWithFormat:@"%.2f",[outgoing.amount floatValue]];

   if([lastOutgoing isEqual:outgoing])
      cell.backgroundColor = [UIColor orangeColor];
   

希望对你有所帮助..

【讨论】：

最初，不添加新单元格，它会改变最后一个单元格的颜色。

@viral - 您不希望第一次加载表格时最后一个单元格颜色不同，仅在添加新单元格/行时更改颜色？

@the_UB，刚刚对初始数据加载应用了另一项验证。

@None 我无法找到输入该方法的数组。你的是dataArray，但我不知道我的是什么

@John，你不需要那个代码。刚刚删除。