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由于项目开始比较急，又是一个人，再加上apple自动布局比较麻烦，衡量以后就用了frame来布局画面。现在稍微闲了一些，就开始对之前的代码做一些优化。其中有一个小功能是这样的，一个可以横向滑动的scrollView，画面加载的时候从服务器取背景图以及文字说明和跳转链接，同时图片做缓存，下一次重新加载的时候如果加载失败，就加载上一次的内容。那么这个地方就涉及了画面，图片缓存两个部分。本文先从画面开始说起。
第一次使用自动布局来写scrollView，就遇到了坑。后来在一个博客中找到了答案。链接如下：UIScrollView添加AutoLayout约束的坑，核心的意思是：
1、scrollView内部子控件的尺寸不能以scrollView的尺寸为参照
2、scrollView内部的子控件的约束必须完整
设计思路，子视图（AdvertisementView）一个view，滚动视图（AdvertisementScrollView）一个view，然后滚动视图中添加scrollView，ViewController里边直接添加滚动视图。
代码如下：
AdvertisementView.h
#import <UIKit/UIKit.h> @interface AdvertisementView : UIView @property (nonatomic, strong) UILabel *textLabel; @property (nonatomic, strong) UILabel *textDetailLabel; - (void)setTextColor:(UIColor *)textColor text:(NSString *)text textDetail:(NSString *)textDetail; @end
AdvertisementView.m
#import "AdvertisementView.h" #import "Define.h" @implementation AdvertisementView - (id)init { self = [super init]; if (self) { self.textLabel = [[UILabel alloc] init]; [self.textLabel setFont:[UIFont fontWithName:FONT_NAME size:15]]; [self.textLabel setTextAlignment:NSTextAlignmentRight]; [self addSubview:self.textLabel]; self.textDetailLabel = [[UILabel alloc] init]; [self.textDetailLabel setFont:[UIFont fontWithName:FONT_NAME size:25]]; [self.textDetailLabel setTextAlignment:NSTextAlignmentRight]; [self addSubview:self.textDetailLabel]; } return self; } - (void)layoutSubviews { [self.textDetailLabel mas_makeConstraints:^(MASConstraintMaker *make) { make.left.equalTo(self).with.offset(0); make.right.equalTo(self).with.offset(-15); make.bottom.equalTo(self).with.offset(-15); make.height.mas_equalTo(@25); }]; [self.textLabel mas_makeConstraints:^(MASConstraintMaker *make) { make.left.equalTo(self).with.offset(0); make.right.equalTo(self).with.offset(-15); make.bottom.equalTo(self.textDetailLabel.mas_top).with.offset(-5); make.height.mas_equalTo(@15); }]; } #pragma mark - load data - (void)setTextColor:(UIColor *)textColor text:(NSString *)text textDetail:(NSString *)textDetail { if (self) { [self.textLabel setText:text]; [self.textLabel setTextColor:textColor]; [self.textDetailLabel setText:textDetail]; [self.textDetailLabel setTextColor:textColor]; } else { NSLog(@"Error : AdvertisementView class is not init successfully."); } } @end
AdvertisementScrollView.h
#import <UIKit/UIKit.h> #import "AdvertisementView.h" @interface AdvertisementScrollView : UIView <UIScrollViewDelegate> { NSArray *_viewArray; } @property (nonatomic, strong) NSArray *viewArray; @end
AdvertisementScrollView.m
#import "AdvertisementScrollView.h" @interface AdvertisementScrollView () @property (nonatomic, strong) UIScrollView *scrollView; @property (nonatomic, strong) UIView *contentView; @property (nonatomic, strong) UIPageControl *pageControl; @end @implementation AdvertisementScrollView - (id)init { self = [super init]; if (self) { [self addSubview:self.scrollView]; } return self; } - (void)layoutSubviews { [super layoutSubviews]; [self.scrollView mas_makeConstraints:^(MASConstraintMaker *make) { make.edges.equalTo(self); }]; [self.pageControl mas_makeConstraints:^(MASConstraintMaker *make) { make.bottom.mas_equalTo(self.mas_bottom); make.centerX.equalTo(self.mas_centerX); make.size.mas_equalTo(CGSizeMake(self.bounds.size.width/2 , 30)); }]; [self.contentView mas_makeConstraints:^(MASConstraintMaker *make) { make.edges.equalTo(self.scrollView); make.height.equalTo(self.scrollView); }]; AdvertisementView *lastAdView = nil; for (AdvertisementView *adView in self.viewArray) { [adView mas_makeConstraints:^(MASConstraintMaker *make) { make.left.equalTo(lastAdView ? lastAdView.mas_right : @0); make.bottom.equalTo(@0); make.width.equalTo(self.scrollView.mas_width); make.height.equalTo(self.scrollView.mas_height); }]; lastAdView = adView; } [self.contentView mas_makeConstraints:^(MASConstraintMaker *make) { make.right.equalTo(lastAdView.mas_right); }]; } #pragma mark - UIScrollViewDelegate - (void)scrollViewDidScroll:(UIScrollView *)scrollView { CGFloat pageWidth = scrollView.frame.size.width; int currentPage = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1; self.pageControl.currentPage = currentPage; } #pragma mark - getters&setters - (UIScrollView *)scrollView { if (_scrollView == nil) { _scrollView = [[UIScrollView alloc] init]; _scrollView.backgroundColor = [UIColor redColor]; _scrollView.delegate = self; _scrollView.bounces = NO; _scrollView.pagingEnabled = YES; _scrollView.showsVerticalScrollIndicator = NO; _scrollView.showsHorizontalScrollIndicator = NO; [_scrollView addSubview:self.contentView]; } return _scrollView; } - (UIView *)contentView { if (_contentView == nil) { _contentView = [[UIView alloc] init]; } return _contentView; } - (UIPageControl *)pageControl { if (_pageControl == nil) { _pageControl = [[UIPageControl alloc] init]; [_pageControl setCurrentPageIndicatorTintColor:[UIColor whiteColor]]; [_pageControl setPageIndicatorTintColor:[UIColor grayColor]]; [_pageControl setCurrentPage:0]; [_pageControl setNumberOfPages:[self.viewArray count]]; } return _pageControl; } - (NSArray *)viewArray { return _viewArray; } - (void)setViewArray:(NSArray *)viewArray { _viewArray = viewArray; for (AdvertisementView *adView in self.viewArray) { [self.contentView addSubview:adView]; } [self addSubview:self.pageControl]; } @end
MainPersonalInfoViewController.h
#import <UIKit/UIKit.h> #import "AdvertisementScrollView.h" #import "AdvertisementView.h" @interface MainPersonalInfoViewController : UIViewController { AdvertisementScrollView *_adScrollView; } @property (nonatomic, strong) AdvertisementScrollView *adScrollView; @end
MainPersonalInfoViewController.m
#import "MainPersonalInfoViewController.h" @interface MainPersonalInfoViewController () @end @implementation MainPersonalInfoViewController - (void)viewDidLoad { [super viewDidLoad]; [self.view addSubview:self.adScrollView]; } - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; [self.adScrollView mas_makeConstraints:^(MASConstraintMaker *make) { make.left.equalTo(self.view).with.offset(0); make.right.equalTo(self.view).with.offset(0); make.top.equalTo(self.view).with.offset(0); make.height.mas_equalTo(@150); }]; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; } #pragma mark - getters&setters - (AdvertisementScrollView *)adScrollView { if (_adScrollView == nil) { _adScrollView = [[AdvertisementScrollView alloc] init]; [_adScrollView setBackgroundColor:[UIColor grayColor]]; AdvertisementView *adView1 = [[AdvertisementView alloc] init]; [adView1 setBackgroundColor:[self randomColor]]; [adView1 setTextColor:[self randomColor] text:@"2.0T四缸又如何？" textDetail:@"测试奥迪Q7 40TFSI S line"]; AdvertisementView *adView2 = [[AdvertisementView alloc] init]; [adView2 setBackgroundColor:[self randomColor]]; [adView2 setTextColor:[self randomColor] text:@"解读低配车" textDetail:@"实拍日产逍客1.2T车型"]; [_adScrollView setViewArray:[@[adView1, adView2] mutableCopy]]; } return _adScrollView; } - (UIColor *)randomColor { CGFloat hue = ( arc4random() % 256 / 256.0 ); // 0.0 to 1.0 CGFloat saturation = ( arc4random() % 128 / 256.0 ) + 0.5; // 0.5 to 1.0, away from white CGFloat brightness = ( arc4random() % 128 / 256.0 ) + 0.5; // 0.5 to 1.0, away from black return [UIColor colorWithHue:hue saturation:saturation brightness:brightness alpha:1]; } @end
以上。
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原文地址：http://www.cnblogs.com/zpz501/p/5112226.html
