在iOS 7的UITableViewCell之间绘制自定义分隔线

问题描述

因为在我要使用自己的UITableViewCell之间使用默认分隔线时遇到了一些麻烦.因此，我正在使用自动布局. C#是我使用的语言.您当然可以在Objective-C中提供解决方案.

Because I had some troubles using the default separator line between the UITableViewCell I want to use my own. Therefore I'm using auto layout. C# is the language I used. You can of course provide solutions in Objective-C.

在我的自定义单元格的构造函数中，添加我的视图UIView:

In the constructor of my custom cell I add my view UIView:

separator = new DividerView ();
ContentView.Superview.AddSubview (separator);

必须将其添加到超级视图中，否则它不会覆盖附件区域.在updateConstraints中，我设置了约束:

One has to add it to the superview otherwise it doesn't cover the accessory area. In updateConstraints I set up my constraints:

separator.TranslatesAutoresizingMaskIntoConstraints = false;

this.ContentView.Superview.AddConstraints (NSLayoutConstraint.FromVisualFormat ("H:|[separator]|", (NSLayoutFormatOptions)0, null, viewsDictionary));
this.ContentView.Superview.AddConstraints (NSLayoutConstraint.FromVisualFormat ("V:|-(82@999)-[separator(1)]|", (NSLayoutFormatOptions)0, null, viewsDictionary));

例如，这确实适用于iOS 8，但不适用于iOS7.同样，此约束V:[separator(1)]|适用于iOS 8，但不适用于iOS 7.

This for example, does work on iOS 8 but not on iOS 7. Also this constraint V:[separator(1)]| would work on iOS 8 but not on iOS 7.

推荐答案

此代码对我有用(UITableViewCell的子类):

This code works for me (subclass of UITableViewCell):

- (void)awakeFromNib {
    // Initialization code
    [super awakeFromNib];
    PCTableViewCellSeparatorView *sV = [[PCTableViewCellSeparatorView alloc] initWithFrame:CGRectMake(0, 0, 0, 1.0)]; // my custom subclass of UIView for drawing 1px line
    sV.backgroundColor = [UIColor clearColor];
    self.accessoryView.backgroundColor = [UIColor clearColor];
    [sV setTranslatesAutoresizingMaskIntoConstraints:NO];
    [self.contentView addSubview:sV];
    // horizontal
    NSNumber *space     = [NSNumber numberWithFloat:0.0f];
    NSNumber *space2    = [NSNumber numberWithFloat:-64.0f]; // MAGIC HERE
    NSDictionary *views = NSDictionaryOfVariableBindings(sV, self.contentView);
    NSDictionary *metrics = NSDictionaryOfVariableBindings(space, space2);
    NSString *horizontalFormat =@"|-space-[sV]-space2-|";
    NSArray* horizontal = [NSLayoutConstraint constraintsWithVisualFormat:horizontalFormat                                                              options:NSLayoutFormatDirectionLeadingToTrailing
                                                              metrics:metrics
                                                                views:views];
    // height
    NSLayoutConstraint *height = [NSLayoutConstraint constraintWithItem:sV attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:0 multiplier:1.0f constant:1.0f];
    // bottom
    NSLayoutConstraint *vertical1 = [NSLayoutConstraint constraintWithItem: sV
                                                             attribute: NSLayoutAttributeBottom
                                                             relatedBy: NSLayoutRelationEqual
                                                                toItem: self.contentView
                                                             attribute: NSLayoutAttributeBottom
                                                            multiplier: 1.0f
                                                              constant: 0.0f
                                 ];
    [self.contentView addConstraints:horizontal];
    [self.contentView addConstraints:@[vertical1,height]];
    self.separatorView = sV; // my own cell's property
}

PCTableViewCellSeparatorView的代码:

Code of PCTableViewCellSeparatorView:

#import <UIKit/UIKit.h>
@interface PCTableViewCellSeparatorView : UIView

@end

#import "PCTableViewCellSeparatorView.h"
#import "UIColor+Utilities.h"

@implementation PCTableViewCellSeparatorView

// -----------------------------------------------------------------------
#pragma mark - Drawing
// -----------------------------------------------------------------------
- (void)drawRect:(CGRect)rect
{
    [super drawRect:rect];

    CGFloat inset;
    switch ([UIScreen screenScale]) {
        case ScreenScale2x:
            inset = 0.5f/2.0f;
            break;
        case ScreenScale3x:
            inset = 0.5f/3.0f;
            break;
        default:
            inset = 0.5f;
            break;
    }

    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);
    // draw
    CGContextSetLineWidth(context, inset);
    CGContextSetStrokeColorWithColor(context, [UIColor colorWithRGB:PCColorGrey].CGColor);
    CGContextMoveToPoint(context, 0, CGRectGetHeight(rect)-inset);
    CGContextAddLineToPoint(context, CGRectGetWidth(rect), CGRectGetHeight(rect)-inset);
    CGContextStrokePath(context);
    CGContextRestoreGState(context);
}

@end

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