ios - 透明的 UITableViewHeaderFooterView

Question

我正在尝试为这个 UITableView 创建一个自定义标题 View ，我希望它是透明的。

我的代码...

界面...

typedef void(^ActionBlock)();

@interface MyViewHeaderView : UITableViewHeaderFooterView

@property (nonatomic, strong) UIImageView *flagImageView;
@property (nonatomic, strong) UILabel *leagueNameLabel;

@property (nonatomic, copy) ActionBlock tapAction;

@end

实现...

#import "MyViewHeaderView.h"

@interface MyViewHeaderView ()

@end

@implementation MyViewHeaderView

- (id)initWithReuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithReuseIdentifier:reuseIdentifier];
    if (self) {
        // Add customisation here...

        // I have tried everything here...
        self.tintColor = [UIColor colorWithWhite:0.961 alpha:1.0];
        self.alpha = 0.5;

        // self.contentView.backgroundColor = [UIColor colorWithWhite:0.5 alpha:0.5];
        // self.backgroundColor = [UIColor colorWithWhite:0.5 alpha:0.5];
        // can't remember what else.
        // none of it makes it transparent. It sets the colour against
        // a white background. i.e. 50% transparent but with a white opaque background.
        // so I can't see the content of the table scrolling behind it.

        self.flagImageView = [[UIImageView alloc] init];
        self.flagImageView.image = [UIImage imageNamed:@"placeholder_flag"];
        [self.flagImageView setTranslatesAutoresizingMaskIntoConstraints:NO];
        [self.contentView addSubview:self.flagImageView];

        self.leagueNameLabel = [[UILabel alloc] init];
        [self.leagueNameLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
        [self.contentView addSubview:self.leagueNameLabel];

        UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(viewTapped)];
        tapGestureRecognizer.numberOfTapsRequired = 1;
        tapGestureRecognizer.numberOfTouchesRequired = 1;
        [self.contentView addGestureRecognizer:tapGestureRecognizer];

        [self setupConstraints];
    }
    return self;
}

- (void)setupConstraints
{
    // adding constraints...
}

- (void)viewTapped
{
    self.tapAction();
}

@end

在我的 UITableViewDelegate 中，我正在加载 header ，例如...

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
    MyViewHeaderView *headerView = [tableView dequeueReusableHeaderFooterViewWithIdentifier:@"HeaderView"];

    League *league = self.leagues[(NSUInteger) section];

    headerView.leagueNameLabel.text = league.name;
    headerView.tapAction = ^(){
        [self leagueTapped:league];
    };

    return headerView;
}

这工作正常，标题显示正确。只是没有透明度。

我想要一个像标准 View 一样的标题 View ，您可以在其中看到在它后面滚动的表格 View 内容。

请告诉我该怎么做。

Answer 1

制作一个具有透明背景颜色的 View 并将其分配给 UITableViewHeaderFooterView 的 backgroundView 属性。

class HeaderView: UITableViewHeaderFooterView{

    override
    init(reuseIdentifier: String?){
        super.init(reuseIdentifier: reuseIdentifier)
        self.backgroundView = UIView()
        self.backgroundView!.backgroundColor = UIColor.clearColor()
    }

    required
    init(coder: NSCoder){
        super.init(coder: coder)
    }

    override
    init(frame: CGRect){
        super.init(frame: frame)
    }
}