【发布时间】：2016-10-12 08:39:16
【问题描述】：
我正在尝试从this 很好的例子开始快速制作日历。到目前为止，我设法展示了自定义 UICollectionViewLayout 的网格和所有补充视图。问题是当我尝试在日历中添加事件时。日期行和日历都在同一个NSMutableDictionary 中，它有一个使用此格式2016-10-12 表示日期（字符串）的键。目标c代码是
-(void)groupEventsBySection{
//toDeviceTimezoneDateString simply take a Date and make a string
_eventsBySection = [mEvents groupBy:@"StartDate.toDeviceTimezoneDateString"].mutableCopy;
// after groupBy is performed _eventsBySection contains only those keys found in mEvents with inside an array of objects {
// "2016-10-12" = (
// "<MSEvent: 0x60000004a680>",
// "<MSEvent: 0x60000004a380>");
// "2016-10-13" = (
// "<MSEvent: 0x600000049b10>");
// "2016-10-17" = (
// "<MSEvent: 0x600000049fc0>");
// }
NSDate* date = [NSDate today:@"device"]; // today's date
if(self.daysToShow == 1 && _eventsBySection.count == 1){
date = [NSDate parse:_eventsBySection.allKeys.firstObject];
}
//here it adds the remaining "daysToShow" if the key doesn't already exist in the MutableDictionary.
for(int i = 0; i< self.daysToShow; i++){
if(![_eventsBySection.allKeys containsObject:date.toDeviceTimezoneDateString]){
[_eventsBySection setObject:@[] forKey:date.toDeviceTimezoneDateString];
}
date = [date addDay]; // this just add one day to date
}
}
到目前为止，这很清楚。问题是当我尝试更改目标 c 中的 groupBy 函数时：
- (NSDictionary*)groupBy:(NSString*)keypath{
return [self groupBy:keypath block:^NSString *(id object, NSString *key) {
return key;
}];
}
- (NSDictionary*)groupBy:(NSString*)keypath block:(NSString*(^)(id object, NSString* key))block{
NSMutableDictionary *result = [NSMutableDictionary new];
NSString* finalKeypath = [NSString stringWithFormat:@"%@.@distinctUnionOfObjects.self",keypath];
NSArray *distinct = [self valueForKeyPath:finalKeypath];
[distinct each:^(NSString* value) {
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K = %@", keypath,value];
NSArray *objects = [self filteredArrayUsingPredicate:predicate];
[result setObject:objects forKey:block(objects[0],value)];
}];
return result;
}
- (NSDictionary*)expand:(NSString*)keypath{
return [self expand:keypath unique:NO];
}
到目前为止，这是我在 swift 中所做的：
我有这个类，在原始代码中是MSEvent
class Event : NSObject {
var title:String?
var location:String?
var startTime:Date?
var endTime:Date?
var duration:Int?
var subtitle:String?
init(startTime: Date, duration: Int, title: String, subtitle: String) {
super.init()
self.startTime = startTime
self.duration = duration
self.title = title
self.subtitle = subtitle
}
我创建了一些假事件：
override func viewDidLoad() {
let today = Date()
let event1 = Event(startTime: today, duration: 60, title: "prova", subtitle: "HEllo")
let event2 = Event(startTime: today, duration: 60, title: "prova", subtitle: "HEllo")
let event3 = Event(startTime: today.dateByAddingDays(days: 1), duration: 60, title: "prova", subtitle: "HEllo")
var array:[Event] = []
array.append(event1)
array.append(event2)
array.append(event3)
calendarView.setEvents(events: array)
}
func setEvents(events:[Event]){
mEvents = events as NSArray
print(mEvents)
//this right now returns the 3 event objects I added:
// (
// "<myapp.Event: 0x60800032ba40>",
// "<myapp.Event: 0x60800032bae0>",
// "<myapp.Event: 0x60800032bcc0>"
// )
self.forceReload(reloadEvent: true) //force reload eventually call the groupEventsBy days
}
func groupEventsByDays(){
// of course everything works without the next line of code
eventsBySection = mEvents.groupBy(keypath: "startTime").mutableCopy() as! NSMutableDictionary
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
var date = dateFormatter.date(from: "2016-10-01")
// right now daysToShow is equal to 30
for _ in 0..<daysToShow{
eventsBySection.setObject([], forKey: self.setFormatDate(date: date!) as NSCopying)
date = self.addDay(date: date!)
}
}
这就是问题所在。这是我的扩展。 扩展 NSArray{
func groupBy(keypath:NSString)->NSDictionary{
return self.groupBy(keypath: keypath, block: { (object, key) -> NSString in
return key
})
}
func groupBy(keypath:NSString,block:@escaping ((_ object: Any, _ key:NSString )-> NSString))-> NSDictionary{
let result:NSMutableDictionary = NSMutableDictionary()
let finalKeypath = String.localizedStringWithFormat("%@.distinctUnionOfObjects.self", keypath)
let distinct:NSArray = self.value(forKey: finalKeypath) as! NSArray
(distinct as AnyObject).each(operation: { (value) in
let predicate = NSPredicate(format: "%K = %@", keypath,value as! CVarArg)
let objects = self.filtered(using: predicate)
result.setObject(objects, forKey: (block(objects[0], value as! NSString)))
})
return result;
}
func each(operation:@escaping ((_ object: AnyObject)-> Void)){
self.enumerateObjects({ (object, idx, stop) in
operation(object as AnyObject)
})
}
}
它因错误this class is not key value coding-compliant for the key startTitle.distinctUnionOfObjects.self.' 而崩溃
我试过像这样使用map
let startDate = array.map ({ $0.startTime })
我设法获得了所有日期（虽然没有不同），但我不知道如何使用 swift 实现上述代码中显示的相同结果。
【问题讨论】：
-
它应该可以工作，但是
self你在哪里查询 NSObject 的子类，并且 startTitle 是一个对 Objective-C 运行时可见的属性？ （即它是否属于与 Objective-C 兼容的类型 - 我根据其名称推测String？） -
啊，没关系，它在一个 NSArray 扩展中，所以
self确实是。但是，关于startTitle的问题仍然存在。
标签： swift swift3 key-value-coding distinct-values