Question

我有一个应用程序，用户可以在桌面视图中喜欢和不喜欢不同的项目。每个表格视图单元格都有一个相似的按钮，单击该按钮时会执行类似的操作，该操作通过在我保存的字典中递增相似计数来记录。然后，用户可以再次单击该按钮而不是该行，因此减少相同的计数。单击like按钮时，将调用以下方法：

- (void)next:(UIButton *)button

现在我正在使用[button setAlpha:0.1];（更改不透明度）来表明它是否被喜欢。 这是我的问题：由于某种原因另一个表格视图单元格受到影响/更改，除了目标单元格！因此，例如，如果我调用此方法并单击第1行，另外，第4行将受到影响。

喜欢和不喜欢的地方叫：

- (void)likeToObject:(BOOL)liked object:(PFObject*)object {
    PFQuery *query = [PFQuery queryWithClassName:@"Item"];
    [query whereKey:@"objectId" equalTo:[object objectId]];
    [query getFirstObjectInBackgroundWithBlock:^(PFObject *foundObject, NSError *error) {
        if (!error) {
            if (liked) {
                int currentLikes = [foundObject[@"likes"] intValue];
                [foundObject setObject:[NSNumber numberWithInt:currentLikes+1] forKey:@"likes"];
                [foundObject saveInBackground];
                [self loadObjects];
                [self.tableView reloadData];
            } else {
                int currentLikes = [foundObject[@"likes"] intValue];
                [foundObject setObject:[NSNumber numberWithInt:currentLikes-1] forKey:@"likes"];
                [foundObject saveInBackground];
                [self loadObjects];
                [self.tableView reloadData];
            }
        } else {
            [self.tableView reloadData];
        }
    }];
}

感谢您的帮助！

编辑：这是我的UI /表格视图代码。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *identifier = @"ParseProduct";
    PFProductTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier forIndexPath:indexPath];
    if (!cell) {
        cell = [[PFProductTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
    }
    PFObject *product = self.objects[indexPath.row];
    [cell configureProduct:product];
    [cell.orderButton addTarget:self action:@selector(next:) forControlEvents:UIControlEventTouchUpInside];
    cell.orderButton.tag = indexPath.row;
    [cell.buyButton addTarget:self action:@selector(buy:) forControlEvents:UIControlEventTouchUpInside];
    cell.buyButton.tag = indexPath.row;
    [cell.shareButton addTarget:self action:@selector(share:) forControlEvents:UIControlEventTouchUpInside];
    cell.shareButton.tag = indexPath.row;
    return cell;
}

- (void)next:(UIButton *)button {
    PFObject *object = [self.objects objectAtIndex:button.tag];
    if (![[likesDict objectForKey:object.objectId] boolValue]) {
        [likesDict setObject:@YES forKey:object.objectId];
        [self likeToObject:YES object:object];
    } else {
        [likesDict setObject:@NO forKey:object.objectId];
        [self likeToObject:NO object:object];
    }
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    [likesDict writeToFile:[documentsDirectory stringByAppendingPathComponent:@"likes.plist"] atomically:YES];
    [button setAlpha:0.1];
}

- (void)configureProduct:(PFObject *)product {
    UIImage *backgroundImage = [UIImage imageNamed:@"Screen Shot 2014-06-16 at 6.34.53 PM.png"];
    UIEdgeInsets backgroundInsets = UIEdgeInsetsMake(backgroundImage.size.height/2.0f, backgroundImage.size.width/2.0f, backgroundImage.size.height/2.0f, backgroundImage.size.width/2.0f);
    UIImageView *backgroundImageView = [[UIImageView alloc] initWithImage:[backgroundImage resizableImageWithCapInsets:backgroundInsets]];
    self.backgroundView = backgroundImageView;
    self.imageView.file = (PFFile *)product[@"image"];
    self.imageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.imageView loadInBackground];
    self.priceLabel.text = [NSString stringWithFormat:@"$%d", [product[@"price"] intValue]];
    self.likeNumberLabel.text = [NSString stringWithFormat:@"%d",[product[@"likes"] intValue]];
    self.textLabel.text = product[@"name"];
    self.textLabel.font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:17.0f];
    self.textLabel.textColor = [UIColor colorWithRed:82.0f/255.0f green:87.0f/255.0f blue:90.0f/255.0f alpha:1.0f];
    self.textLabel.shadowColor = [UIColor colorWithWhite:1.0f alpha:0.7f];
    self.textLabel.shadowOffset = CGSizeMake(0.0f, 0.5f);
    self.textLabel.backgroundColor = [UIColor clearColor];
    self.textLabel.numberOfLines = 2;
    if ([product[@"hasSize"] boolValue]) {
        self.sizeButton = [UIButton buttonWithType:UIButtonTypeCustom];
        self.sizeButton.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
        [self.sizeButton setTitle:NSLocalizedString(@"Select Size", @"Select Size") forState:UIControlStateNormal];
        [self.sizeButton setTitleColor:[UIColor colorWithRed:95.0f/255.0f green:95.0f/255.0f blue:95.0f/255.0f alpha:1.0f] forState:UIControlStateNormal];
        [self.sizeButton setTitleEdgeInsets:UIEdgeInsetsMake(0.0f, 16.0f, 0.0f, 0.0f)];
        self.sizeButton.titleLabel.font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:16.0f];
        [self.sizeButton setTitleShadowColor:[UIColor whiteColor] forState:UIControlStateNormal];
        self.sizeButton.titleLabel.textColor = [UIColor colorWithRed:95.0f/255.0f green:95.0f/255.0f blue:90.0f/255.0f alpha:1.0f];
        self.sizeButton.titleLabel.shadowOffset = CGSizeMake(0.0f, 0.5f);
        UIImage *sizeImage = [UIImage imageNamed:@"DropdownButton.png"];
        UIImage *sizePressedImage = [UIImage imageNamed:@"DropdownButtonPressed.png"];
        UIEdgeInsets insets = UIEdgeInsetsMake(sizeImage.size.height/2, sizeImage.size.width/2, sizeImage.size.height/2, sizeImage.size.width/2);
        [self.sizeButton setBackgroundImage:[sizeImage resizableImageWithCapInsets:insets] forState:UIControlStateNormal];
        [self.sizeButton setBackgroundImage:[sizePressedImage resizableImageWithCapInsets:insets] forState:UIControlStateHighlighted];
        UIImage *arrowImage = [UIImage imageNamed:@"Arrow.png"];
        UIImageView *arrowView = [[UIImageView alloc] initWithImage:arrowImage];
        arrowView.frame = CGRectMake(140.0f, (40.0f - arrowImage.size.height)/2.0f, arrowImage.size.width, arrowImage.size.height);
        [self.sizeButton addSubview:arrowView];
        [self addSubview:self.sizeButton];

    }
}

Answer 1

我花了一些时间编辑你的问题来清理代码和英语。我还发现你正在初始化orderButton以及表视图初始化中的其他按钮。每个按钮应该是一个新创建的表视图单元实例！将按钮分配给新初始化的UIButton实例，并设置视图属性，所有这些都在cellForRowAtIndexPath:内。原因是，当您更改按钮的不透明度时，该按钮被分配给多个表视图单元格，因此其他单元格也会更改。第四个表视图单元格正在改变的原因，我可能是错的，也许是你必须滚动到的那个，因此它正在重新加载具有该不透明度集的视图。

此外，我认为将这些设置写入字典并通过plist将其保存在文件系统中是一种非常糟糕的设计。我要做的是子类PFObject并拥有自己的自定义类，它存储一个布尔属性，如isLiked，这样值就会直接存储到指针中，你可以评估以下操作/步骤从数组中检索对象并评估isLiked（然后可以更改）。

Answer 2

此代码应该这样做

- (void)next:(UIButton *)button {
NSLog(@"nextButton");

PFQuery *query = [PFQuery queryWithClassName:@"Item"];
PFObject *object = [self.objects objectAtIndex:button.tag];

[query whereKey:@"objectId" equalTo:[object objectId]];

if ([[likesDict objectForKey:object.objectId] boolValue] == NO) {
    [likesDict setObject:[NSNumber numberWithBool:YES] forKey:[NSString stringWithFormat:@"%@",object.objectId]];
    [button setTitle:@"unlike" forState:UIControlStateNormal];
    [self likeToObject:YES object:object];
} else if ([[likesDict objectForKey:object.objectId] boolValue] == YES) {
    [likesDict setObject:[NSNumber numberWithBool:NO] forKey:[NSString stringWithFormat:@"%@",object.objectId]];
    [button setTitle:@"like" forState:UIControlStateNormal];
    [self likeToObject:NO object:object];
}
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
[likesDict writeToFile:[documentsDirectory stringByAppendingPathComponent:@"likes.plist"] atomically:YES];

}

在表视图上选择后更改按钮状态

2 个答案: