这几天一直在进行知乎日报的仿写，仿写过程中积累了许多实用的开发经验，并对MVC有了更深的了解，特撰此篇作以总结
目录
第一周
将网络请求封装在一个单例类Manager中
由于知乎日报所请求的API较多，若将网络请求三板斧直接写在Controller中会代码十分冗杂，干脆直接将AFNetWorking和JSONModel封装到一个全局的Manager单例类中，在Manager类中进行网络请求和数据解析，不同的API写成不同的方法，具体实现看这篇博客（）
typedef void(^LatestStoriesBlock)(LatestStoriesModel* latestStoriesModel);
typedef void(^BeforeStoriesModelBlock)(StoriesModel* beforeStoriesModel);
typedef void(^StoriesContentBlock)(StoriesContentModel* storiesContentModel);
typedef void(^StoriesExtraContentBlock)(StoriesExtraContentModel* storiesExtraContentModel);
typedef void(^ErrorBlock)(NSError* error);
@interface Manager : NSObject
//单例实例
+ (instancetype)sharedManager;
//请求最新消息
- (void)requestTopStoriesData: (LatestStoriesBlock)success failure: (ErrorBlock)failure;
//缓存网络图片
+ (void)setImage: (id)imageView WithString: (NSString *)string;
//请求指定日期的消息内容
- (void)requestBeforeDate: (NSString *)date beforeStoriesData: (BeforeStoriesModelBlock)success failure: (ErrorBlock)failure;
//加载Web网页在WebView中
- (void)setWebView: (WKWebView *)webView WithString: (NSString *)string;
//请求指定网页的内容（主要为了获取share_url）
- (void)requestWebContentWithID: (NSString *)string StoriesContentData: (StoriesContentBlock)success failure: (ErrorBlock)failure;
//请求制定网页的额外内容
- (void)requestExtraContentWithID: (NSString *)string StoriesExtraContentData: (StoriesExtraContentBlock)success failure: (ErrorBlock)failure;
@end
解析下来的数据用Block传值（【iOS】属性传值、代理传值（委托）、通知传值、KVO传值、Block传值、单例传值）的方式在Controller中接收
SDWebImage库的简单使用
使用WebImage库主要是为了缓存网络图片并加载在UIImageView上，只需在loadRequest:方法中传入指定的NSURL
+ (void)setImage:(UIImageView *)imageView WithString:(NSString *)string {
string = [string stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
NSURL* url = [NSURL URLWithString:string];
[imageView sd_setImageWithURL: url placeholderImage: [UIImage imageNamed: @"placeholder.png"]];
}
运用时间戳处理当前时间
处理方法单独写在一个工具类中方便管理
@interface DateModel : NSObject
+ (NSTimeInterval)getTimestampWithTimeString: (NSString *)timeString;
+ (NSString *)getMonthWithTimeString: (NSString *)timeString;
+ (NSString *)getDayWithTimeString: (NSString *)timeString;
+ (NSString *)getDateWithTimeString: (NSString *)timeString;
+ (NSString *)getBeforeDateWithTimeString: (NSString *)timeString;
@end
获取时间戳方法
//传入时间格式：20230917
+ (NSTimeInterval)getTimestampWithTimeString: (NSString *)timeString {
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat: @"YYYYMMdd"];
NSDate* date = [dateFormatter dateFromString: timeString];
NSTimeInterval timeStamp = [date timeIntervalSince1970];
return timeStamp;
}
通过时间戳处理指定时间
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
//YYYY获取年份 MM获取月份 dd获取日份
//当然也可以混用，如：@"MM月dd日"，这样就会得到一个指定格式的时间字符串
[dateFormatter setDateFormat: @"MM"];
NSTimeInterval timeStamp = [self getTimestampWithTimeString: timeString];
NSDate* date = [NSDate dateWithTimeIntervalSince1970: timeStamp];
NSString* string = [dateFormatter stringFromDate: date];
自定义NavigationBar
在push页面过程中，使用系统的NavigationBar会发现UI是逐渐消失的，而知乎日报App是第二个页面直接覆盖过去的，想不到什么实现这种效果的巧妙方法，这里我直接在NavigationBar的位置直接粘上一个UIView，并在当前控制器隐藏NavigationBar
- (void)viewWillAppear:(BOOL)animated {
[self.navigationController setNavigationBarHidden: YES animated: YES];
}
- (void)viewWillDisappear:(BOOL)animated {
[self.navigationController setNavigationBarHidden: NO animated: YES];
}
这两个方法涉及UIViewController的生命周期【iOS】ViewController生命周期
第二周
在UITableView的section之间的headerView上画UI
tableView提供了这样一个协议方法自定义section
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
if (section > 1) {
UIView* view = [[UIView alloc] init];
UILabel* dateLabel = [[UILabel alloc] init];
dateLabel.textColor = [UIColor grayColor];
dateLabel.font = [UIFont boldSystemFontOfSize: 15];
dateLabel.text = [DateModel getDateWithTimeString: self.beforeDateArray[section - 1]];
[view addSubview: dateLabel];
UIView* grayView = [[UIView alloc] init];
grayView.backgroundColor = [UIColor colorWithRed: 231.0 / 255 green: 231.0 / 255 blue: 231.0 / 255 alpha: 1];
[view addSubview: grayView];
[dateLabel makeConstraints:^(MASConstraintMaker *make) {
make.left.equalTo(view.left).offset(MINIGAP);
make.centerY.equalTo(view.centerY);
}];
[grayView makeConstraints:^(MASConstraintMaker *make) {
make.height.equalTo(1);
make.left.equalTo(dateLabel.right).offset(MINIGAP);
make.right.equalTo(view.right);
make.centerY.equalTo(view.centerY);
}];
return view;
} else {
return nil;
}
}
但section之间的距离跟返回view的高度是没有关系的，要想消除分区之间的留白，给以下属性赋值即可
self.tableView.sectionHeaderTopPadding = 0;
WKWebView的使用
只需传入NSRequest即可在webView上加载web网页
- (void)setWebView:(WKWebView *)webView WithString:(NSString *)string {
//NSLog(@"%@", string);
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString: string]];
[webView loadRequest: request];
}
WKWebView网页加载不出来
大概查了一下
出现加载不出来本质原因是，如果没在plist文件中设置App Transport Security Settings的话，加载https链接，肯定是加载不出来的，第一次加载不出来，产生了缓存，第二次再去加载也加载不出来了，可以尝试一下就知道了
线程问题
网络请求是在Controller中调用的，请求下来的数据会赋值给View的各种属性，但请求是需要时间的，如果在viewDidLoad里面先初始化view，那么还没等数据请求下来，UI就已经布局，那么只会显示空白的UI控件，未解决这一问题，用到了GCD的一个方法：
dispatch_async(dispatch_get_main_queue(), ^{
[self sendViewStories: latestStoriesModel];
[self createTopImages];
[self setViewAndModel];
[self requestBeforeStoriesWithDate: self.latestStoriesModel.date];
});
第三周
attempting to add unsupported attribute: (null)错误
使用masonry，设置约束时，约束冲突或约束不全
解决方法就是补充必要的约束或者调整调用顺序
FMDB数据库的简单使用
FMDB库将C语言风格的MySqlite数据库封装成了OC风格的方法，而且操作比C语言文件操作更容易
以点赞集合（存储相应网页的ID）为例，实现了数据库的增删改查：
#pragma mark 点赞操作
- (void)createStoriesLikeSet {
NSString* doc = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString* fileName = [doc stringByAppendingPathComponent: @"likeDatabase.sqlite"];
NSLog(@"%@", fileName);
self.likeDatabase = [FMDatabase databaseWithPath: fileName];
if ([self.likeDatabase open]) {
BOOL result = [self.likeDatabase executeUpdate: @"CREATE TABLE IF NOT EXISTS likeDatabase (idLabel text NOT NULL)"];
if (result) {
FMResultSet* resultSet = [self.likeDatabase executeQuery: @"SELECT * FROM likeDatabase"];
while([resultSet next]) {
[self.storiesLikeSet addObject:[resultSet stringForColumn: @"idLabel"]];
}
NSLog(@"create table succeed");
} else {
NSLog(@"fail to open database");
}
[self.likeDatabase close];
}
}
- (void)saveStoriesLikeSet {
if ([self.likeDatabase open]) {
for (NSString* ID in self.storiesLikeSet) {
FMResultSet* resultSet = [self.likeDatabase executeQuery: @"SELECT * FROM likeDatabase WHERE idLabel = ?", ID];
if (![resultSet next]) {
BOOL result = [self.likeDatabase executeUpdate: @"INSERT INTO likeDatabase (idLabel) VALUES (?)", ID];
if (result) {
NSLog(@"insert table succeed");
} else {
NSLog(@"insert table error");
}
}
}
[self.likeDatabase close];
}
}
- (void)deleteLikeSetWithID:(NSString*)ID {
if ([self.likeDatabase open]) {
BOOL result = [self.likeDatabase executeUpdate: @"delete from likeDatabase WHERE idLabel = ?", ID];
if (result) {
NSLog(@"delete table succeed");
} else {
NSLog(@"delete table error");
}
[self.likeDatabase close];
}
}
WebView界面无限右滑
向右加载新一天的消息时，主页的tableViewCell也要更新，这里使用了通知中心进行消息传递
if (self.scrollView.contentOffset.x == Screen_WIDTH * self.numberOfStories) {
[[NSNotificationCenter defaultCenter] postNotificationName: @"upDateRight" object: nil];
return;
}
滑到了新增加的画布时，先通知首页更新一天数据：
//更新首页
[[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(upDateRight) name: @"upDateRight" object: nil];
- (void) upDateRight {
StoriesModel* storiesModel = [self.beforeStoriesModelArray lastObject];
NSString* beforeDate = storiesModel.date;
[self requestBeforeStoriesWithDate: beforeDate];
}
然后将更新后的数据传回WebView相关页面，加载新的Web
- (void)requestBeforeStoriesWithDate: (NSString *)date {
[self.manager requestBeforeDate: date beforeStoriesData:^(StoriesModel * _Nonnull beforeStoriesModel) {
if (!self.beforeStoriesModelArray) {
self.beforeStoriesModelArray = [[NSMutableArray alloc] init];
}
[self.beforeStoriesModelArray addObject: beforeStoriesModel];
//NSLog(@"%@", beforeStoriesModel.date);
dispatch_async(dispatch_get_main_queue(), ^{
[self sendViewStories: beforeStoriesModel];
self.mainView.isLoading = NO;
[self.mainView.tableView reloadData];
NSMutableArray* storiesArray = [[NSMutableArray alloc] init];
for (Stories* stories in beforeStoriesModel.stories) {
[storiesArray addObject: stories.id];
}
[[NSNotificationCenter defaultCenter] postNotificationName: @"upDateRight-Two" object:nil userInfo: @{@"value" : storiesArray}];
});
} failure:^(NSError * _Nonnull error) {
NSLog(@"请求过往消息失败");
}];
}
但这里面遇到了数组越界问题，向右滑着滑着就访问到了不存在的索引，目前尚未解决
源码
这里先挂一个半成品，之后会想办法解决这个bug，并尝试实现评论区、收藏夹和夜间模式等。