DZNEmptyDataSet，优秀的空白页或者出错页封装

## 简单介绍

项目主页:https://github.com/dzenbot/DZNEmptyDataSet

提示：主要用于UITableView和UICollectionView，也能够用于UIScrollView，事实上主要是前两个会用到空白或者网络出错页

採用给UIScrollView加入代理方法来给页面加入空白页，源代码非常有学习意义

导入project

自己主动。

pod 'DZNEmptyDataSet'

手动

https://github.com/dzenbot/DZNEmptyDataSet 下载解压，Source目录下的文件拖入project

导入头文件：

#import "UIScrollView+EmptyDataSet.h"

初始化

    @interface MainViewController : UITableViewController <DZNEmptyDataSetSource, DZNEmptyDataSetDelegate>

    － (void)viewDidLoad {
         [super viewDidLoad];

         self.tableView.emptyDataSetSource = self;
         self.tableView.emptyDataSetDelegate = self;

    //这行代码必须加上，能够去除tableView的多余的线，否则会影响美观
         self.tableView.tableFooterView = [UIView new];
    }

满足代理方法，能够分别配置，都是可选的

空白页图片

    - (UIImage *)imageForEmptyDataSet:(UIScrollView *)scrollView {
    return [UIImage imageNamed:@"empty_placeholder"];
    }

图片的动画效果

    - (CAAnimation *)imageAnimationForEmptyDataSet:(UIScrollView *)scrollView {
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath: @"transform"];

    animation.fromValue = [NSValue valueWithCATransform3D:CATransform3DIdentity];
    animation.toValue = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(M_PI_2, 0.0, 0.0, 1.0)];

    animation.duration = 0.25;
    animation.cumulative = YES;
    animation.repeatCount = MAXFLOAT;

    return animation;
    }

标题文本。具体描写叙述。富文本样式

    - (NSAttributedString *)titleForEmptyDataSet:(UIScrollView *)scrollView {
    NSString *text = @"Please Allow Photo Access";

    NSDictionary *attributes = @{NSFontAttributeName: [UIFont boldSystemFontOfSize:18.0f],
                                 NSForegroundColorAttributeName: [UIColor darkGrayColor]};

    return [[NSAttributedString alloc] initWithString:text attributes:attributes];
    }

    - (NSAttributedString *)descriptionForEmptyDataSet:(UIScrollView *)scrollView {
    NSString *text = @"This allows you to share photos from your library and save photos to your camera roll.";

    NSMutableParagraphStyle *paragraph = [NSMutableParagraphStyle new];
    paragraph.lineBreakMode = NSLineBreakByWordWrapping;
    paragraph.alignment = NSTextAlignmentCenter;

    NSDictionary *attributes = @{NSFontAttributeName: [UIFont systemFontOfSize:14.0f],
                                 NSForegroundColorAttributeName: [UIColor lightGrayColor],
                                 NSParagraphStyleAttributeName: paragraph};

    return [[NSAttributedString alloc] initWithString:text attributes:attributes];                      
    }

按钮文本或者背景样式

    - (NSAttributedString *)buttonTitleForEmptyDataSet:(UIScrollView *)scrollView forState:(UIControlState)state {
    NSDictionary *attributes = @{NSFontAttributeName: [UIFont boldSystemFontOfSize:17.0f]};

    return [[NSAttributedString alloc] initWithString:@"Continue" attributes:attributes];
    }

    - (UIImage *)buttonImageForEmptyDataSet:(UIScrollView *)scrollView forState:(UIControlState)state {
    return [UIImage imageNamed:@"button_image"];
    }

空白页的背景色

    - (UIColor *)backgroundColorForEmptyDataSet:(UIScrollView *)scrollView {
    return [UIColor whiteColor];
    }

假设需求无法满足。你能够自己定义

    - (UIView *)customViewForEmptyDataSet:(UIScrollView *)scrollView {
    //加入你自己定义的view
    UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    [activityView startAnimating];
    return activityView;
    }

其它需求

    //是否显示空白页。默认YES
    - (BOOL)emptyDataSetShouldDisplay:(UIScrollView *)scrollView {
    return YES;
    }

    //是否同意点击，默认YES
    - (BOOL)emptyDataSetShouldAllowTouch:(UIScrollView *)scrollView {
    return YES;
    }

    //是否同意滚动，默认NO
    - (BOOL)emptyDataSetShouldAllowScroll:(UIScrollView *)scrollView {
    return YES;
    }

    //图片是否要动画效果，默认NO
    - (BOOL) emptyDataSetShouldAllowImageViewAnimate:(UIScrollView *)scrollView {
    return YES;
    }

    //空白页点击事件
    - (void)emptyDataSetDidTapView:(UIScrollView *)scrollView {

    }

    //空白页按钮点击事件
    - (void)emptyDataSetDidTapButton:(UIScrollView *)scrollView {

    }

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