ios - 如何在 UICollectionViewCell 上显示标准复选标记？

Question

我正在设计一个带有 UICollectionView 的 iOS 应用程序，我希望用户能够在此 View 中选择多个项目。 Apple 在这种情况下似乎使用了一种标准样式的复选标记。例如，在下图中，您可以在共享表中选择多张照片时看到它。

根据documentation ，您负责更新单元格的 UI 以反射(reflect)它们的选择状态。我知道在 UITableViewCell 上你可以设置 accessoryType 属性来添加复选标记，但我似乎找不到 UICollectionViewCell 的任何等效项。

除了尝试从屏幕截图中删除此图标外，Apple 是否提供了一种在我的应用程序中使用此复选标记的方法？

Answer 1

我最终使用 PaintCode 重新创建了复选标记.它们的外观如下:

它们是用矢量图形绘制的，因此无论您想要什么尺寸，它们都会看起来很棒。这些是 30x30。我还包括一个选项，可以在未选择项目时使用灰色复选标记而不是空心圆圈。

要使用这些，请将以下类复制到您的项目中。然后，将 UIView 添加到您的 Storyboard或 xib，并将其自定义类设置为 SSCheckMark。

SSCheckMark.h

#import <UIKit/UIKit.h>

typedef NS_ENUM( NSUInteger, SSCheckMarkStyle )
{
    SSCheckMarkStyleOpenCircle,
    SSCheckMarkStyleGrayedOut
};

@interface SSCheckMark : UIView

@property (readwrite) bool checked;
@property (readwrite) SSCheckMarkStyle checkMarkStyle;

@end

SSCheckMark.m

#import "SSCheckMark.h"

@implementation SSCheckMark

- (void) drawRect:(CGRect)rect
{
    [super drawRect:rect];

    if ( self.checked )
        [self drawRectChecked:rect];
    else
    {
        if ( self.checkMarkStyle == SSCheckMarkStyleOpenCircle )
            [self drawRectOpenCircle:rect];
        else if ( self.checkMarkStyle == SSCheckMarkStyleGrayedOut )
            [self drawRectGrayedOut:rect];
    }
}

- (void) setChecked:(bool)checked
{
    _checked = checked;
    [self setNeedsDisplay];
}

- (void) setCheckMarkStyle:(SSCheckMarkStyle)checkMarkStyle
{
    _checkMarkStyle = checkMarkStyle;
    [self setNeedsDisplay];
}

- (void) drawRectChecked: (CGRect) rect
{
    //// General Declarations
    CGContextRef context = UIGraphicsGetCurrentContext();

    //// Color Declarations
    UIColor* checkmarkBlue2 = [UIColor colorWithRed: 0.078 green: 0.435 blue: 0.875 alpha: 1];

    //// Shadow Declarations
    UIColor* shadow2 = [UIColor blackColor];
    CGSize shadow2Offset = CGSizeMake(0.1, -0.1);
    CGFloat shadow2BlurRadius = 2.5;

    //// Frames
    CGRect frame = self.bounds;

    //// Subframes
    CGRect group = CGRectMake(CGRectGetMinX(frame) + 3, CGRectGetMinY(frame) + 3, CGRectGetWidth(frame) - 6, CGRectGetHeight(frame) - 6);


    //// Group
    {
        //// CheckedOval Drawing
        UIBezierPath* checkedOvalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(CGRectGetMinX(group) + floor(CGRectGetWidth(group) * 0.00000 + 0.5), CGRectGetMinY(group) + floor(CGRectGetHeight(group) * 0.00000 + 0.5), floor(CGRectGetWidth(group) * 1.00000 + 0.5) - floor(CGRectGetWidth(group) * 0.00000 + 0.5), floor(CGRectGetHeight(group) * 1.00000 + 0.5) - floor(CGRectGetHeight(group) * 0.00000 + 0.5))];
        CGContextSaveGState(context);
        CGContextSetShadowWithColor(context, shadow2Offset, shadow2BlurRadius, shadow2.CGColor);
        [checkmarkBlue2 setFill];
        [checkedOvalPath fill];
        CGContextRestoreGState(context);

        [[UIColor whiteColor] setStroke];
        checkedOvalPath.lineWidth = 1;
        [checkedOvalPath stroke];


        //// Bezier Drawing
        UIBezierPath* bezierPath = [UIBezierPath bezierPath];
        [bezierPath moveToPoint: CGPointMake(CGRectGetMinX(group) + 0.27083 * CGRectGetWidth(group), CGRectGetMinY(group) + 0.54167 * CGRectGetHeight(group))];
        [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(group) + 0.41667 * CGRectGetWidth(group), CGRectGetMinY(group) + 0.68750 * CGRectGetHeight(group))];
        [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(group) + 0.75000 * CGRectGetWidth(group), CGRectGetMinY(group) + 0.35417 * CGRectGetHeight(group))];
        bezierPath.lineCapStyle = kCGLineCapSquare;

        [[UIColor whiteColor] setStroke];
        bezierPath.lineWidth = 1.3;
        [bezierPath stroke];
    }
}

- (void) drawRectGrayedOut: (CGRect) rect
{
    //// General Declarations
    CGContextRef context = UIGraphicsGetCurrentContext();

    //// Color Declarations
    UIColor* grayTranslucent = [UIColor colorWithRed: 1 green: 1 blue: 1 alpha: 0.6];

    //// Shadow Declarations
    UIColor* shadow2 = [UIColor blackColor];
    CGSize shadow2Offset = CGSizeMake(0.1, -0.1);
    CGFloat shadow2BlurRadius = 2.5;

    //// Frames
    CGRect frame = self.bounds;

    //// Subframes
    CGRect group = CGRectMake(CGRectGetMinX(frame) + 3, CGRectGetMinY(frame) + 3, CGRectGetWidth(frame) - 6, CGRectGetHeight(frame) - 6);


    //// Group
    {
        //// UncheckedOval Drawing
        UIBezierPath* uncheckedOvalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(CGRectGetMinX(group) + floor(CGRectGetWidth(group) * 0.00000 + 0.5), CGRectGetMinY(group) + floor(CGRectGetHeight(group) * 0.00000 + 0.5), floor(CGRectGetWidth(group) * 1.00000 + 0.5) - floor(CGRectGetWidth(group) * 0.00000 + 0.5), floor(CGRectGetHeight(group) * 1.00000 + 0.5) - floor(CGRectGetHeight(group) * 0.00000 + 0.5))];
        CGContextSaveGState(context);
        CGContextSetShadowWithColor(context, shadow2Offset, shadow2BlurRadius, shadow2.CGColor);
        [grayTranslucent setFill];
        [uncheckedOvalPath fill];
        CGContextRestoreGState(context);

        [[UIColor whiteColor] setStroke];
        uncheckedOvalPath.lineWidth = 1;
        [uncheckedOvalPath stroke];


        //// Bezier Drawing
        UIBezierPath* bezierPath = [UIBezierPath bezierPath];
        [bezierPath moveToPoint: CGPointMake(CGRectGetMinX(group) + 0.27083 * CGRectGetWidth(group), CGRectGetMinY(group) + 0.54167 * CGRectGetHeight(group))];
        [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(group) + 0.41667 * CGRectGetWidth(group), CGRectGetMinY(group) + 0.68750 * CGRectGetHeight(group))];
        [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(group) + 0.75000 * CGRectGetWidth(group), CGRectGetMinY(group) + 0.35417 * CGRectGetHeight(group))];
        bezierPath.lineCapStyle = kCGLineCapSquare;

        [[UIColor whiteColor] setStroke];
        bezierPath.lineWidth = 1.3;
        [bezierPath stroke];
    }
}

- (void) drawRectOpenCircle: (CGRect) rect
{
    //// General Declarations
    CGContextRef context = UIGraphicsGetCurrentContext();


    //// Shadow Declarations
    UIColor* shadow = [UIColor blackColor];
    CGSize shadowOffset = CGSizeMake(0.1, -0.1);
    CGFloat shadowBlurRadius = 0.5;
    UIColor* shadow2 = [UIColor blackColor];
    CGSize shadow2Offset = CGSizeMake(0.1, -0.1);
    CGFloat shadow2BlurRadius = 2.5;

    //// Frames
    CGRect frame = self.bounds;

    //// Subframes
    CGRect group = CGRectMake(CGRectGetMinX(frame) + 3, CGRectGetMinY(frame) + 3, CGRectGetWidth(frame) - 6, CGRectGetHeight(frame) - 6);


    //// Group
    {
        //// EmptyOval Drawing
        UIBezierPath* emptyOvalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(CGRectGetMinX(group) + floor(CGRectGetWidth(group) * 0.00000 + 0.5), CGRectGetMinY(group) + floor(CGRectGetHeight(group) * 0.00000 + 0.5), floor(CGRectGetWidth(group) * 1.00000 + 0.5) - floor(CGRectGetWidth(group) * 0.00000 + 0.5), floor(CGRectGetHeight(group) * 1.00000 + 0.5) - floor(CGRectGetHeight(group) * 0.00000 + 0.5))];
        CGContextSaveGState(context);
        CGContextSetShadowWithColor(context, shadow2Offset, shadow2BlurRadius, shadow2.CGColor);
        CGContextRestoreGState(context);

        CGContextSaveGState(context);
        CGContextSetShadowWithColor(context, shadowOffset, shadowBlurRadius, shadow.CGColor);
        [[UIColor whiteColor] setStroke];
        emptyOvalPath.lineWidth = 1;
        [emptyOvalPath stroke];
        CGContextRestoreGState(context);
    }
}

@end