27_Blog Reader

这个App是用来读取 Official Google Blog 的内容，然后显示出来。

用了新建工程时用了 Master-Detail Application 这个模板。用了Core Data用来存储内容，不过每次启动App还是会删除内容，然后重新下载最新的20条。所以如果没有网络的时候打开不显示内容。

在原工程的基础上，我在Core Data中增加了date这项，为了排列时按照时间排列。获取的内容中有published和updated两个时间，用published好一些。这里只简单的转了String而不是Date类型。

//
//  MasterViewController.swift
//  Blog Reader
//
//  Created by zcdll on 16/1/24.
//  Copyright © 2016年 ZC. All rights reserved.
//

import UIKit
import CoreData

class MasterViewController: UITableViewController, NSFetchedResultsControllerDelegate {

    var detailViewController: DetailViewController? = nil
    var managedObjectContext: NSManagedObjectContext? = nil

    override func viewDidLoad() {
        super.viewDidLoad()

        let appDel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

        let context: NSManagedObjectContext = appDel.managedObjectContext

        let url = NSURL(string: "https://www.googleapis.com/blogger/v3/blogs/10861780/posts?key=AIzaSyCxL3Iltcd-oLc-dFUtdDG9TTuJGWilsYw")!

        let session = NSURLSession.sharedSession()

        let task = session.dataTaskWithURL(url) { (data, response, error) -> Void in

            if error != nil {

                print(error)

            } else {

                if let data = data {

                    //print(NSString(data: data, encoding: NSUTF8StringEncoding))

                    do {

                        let jsonResult = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers) as! NSDictionary

                        if jsonResult.count > 0 {

                            if let items = jsonResult["items"] as? NSArray {

                                let request = NSFetchRequest(entityName: "BlogItems")

                                request.returnsObjectsAsFaults = false

                                do {

                                    let results = try context.executeFetchRequest(request)

                                    if results.count > 0 {

                                        for result in results {

                                            context.deleteObject(result as! NSManagedObject)

                                            do { try context.save() } catch {}

                                        }

                                    }

                                } catch {

                                    print("Context fetched failed")

                                }

                                for item in items {

                                    if let title = item["title"] as? String {

                                        if let content = item["content"] as? String {

                                            if let date = item["published"] as? String {

                                                let updatedDate = date.componentsSeparatedByString("-08:00")[0]

                                                print(updatedDate)

                                                //print(title)
                                                //print(content)

                                                let newPost: NSManagedObject = NSEntityDescription.insertNewObjectForEntityForName("BlogItems", inManagedObjectContext: context)

                                                newPost.setValue(title, forKey: "title")
                                                newPost.setValue(content, forKey: "content")
                                                newPost.setValue(updatedDate, forKey: "date")

                                            }

                                        }

                                    }

                                    //print(items)
                                }

                            }

                        }

                    } catch {}

                }

            }

        }

        task.resume()

        // Do any additional setup after loading the view, typically from a nib.
        if let split = self.splitViewController {
            let controllers = split.viewControllers
            self.detailViewController = (controllers[controllers.count-1] as! UINavigationController).topViewController as? DetailViewController
        }
    }

    override func viewWillAppear(animated: Bool) {
        self.clearsSelectionOnViewWillAppear = self.splitViewController!.collapsed
        super.viewWillAppear(animated)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Segues

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "showDetail" {
            if let indexPath = self.tableView.indexPathForSelectedRow {
            let object = self.fetchedResultsController.objectAtIndexPath(indexPath)
                let controller = (segue.destinationViewController as! UINavigationController).topViewController as! DetailViewController
                controller.detailItem = object
                controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
                controller.navigationItem.leftItemsSupplementBackButton = true
            }
        }
    }

    // MARK: - Table View

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let sectionInfo = self.fetchedResultsController.sections![section]
        return sectionInfo.numberOfObjects
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
        self.configureCell(cell, atIndexPath: indexPath)
        return cell
    }

    override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }

    override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
        if editingStyle == .Delete {
            let context = self.fetchedResultsController.managedObjectContext
            context.deleteObject(self.fetchedResultsController.objectAtIndexPath(indexPath) as! NSManagedObject)

            do {
                try context.save()
            } catch {
                // Replace this implementation with code to handle the error appropriately.
                // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                //print("Unresolved error \(error), \(error.userInfo)")
                abort()
            }
        }
    }

    func configureCell(cell: UITableViewCell, atIndexPath indexPath: NSIndexPath) {
        let object = self.fetchedResultsController.objectAtIndexPath(indexPath)
        cell.textLabel!.text = object.valueForKey("title")!.description
    }

    // MARK: - Fetched results controller

    var fetchedResultsController: NSFetchedResultsController {
        if _fetchedResultsController != nil {
            return _fetchedResultsController!
        }

        let fetchRequest = NSFetchRequest()
        // Edit the entity name as appropriate.
        let entity = NSEntityDescription.entityForName("BlogItems", inManagedObjectContext: self.managedObjectContext!)
        fetchRequest.entity = entity

        // Set the batch size to a suitable number.
        fetchRequest.fetchBatchSize = 20

        // Edit the sort key as appropriate.
        let sortDescriptor = NSSortDescriptor(key: "date", ascending: false)

        fetchRequest.sortDescriptors = [sortDescriptor]

        // Edit the section name key path and cache name if appropriate.
        // nil for section name key path means "no sections".
        let aFetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: self.managedObjectContext!, sectionNameKeyPath: nil, cacheName: "Master")
        aFetchedResultsController.delegate = self
        _fetchedResultsController = aFetchedResultsController

        do {
            try _fetchedResultsController!.performFetch()
        } catch {
             // Replace this implementation with code to handle the error appropriately.
             // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
             //print("Unresolved error \(error), \(error.userInfo)")
             abort()
        }

        return _fetchedResultsController!
    }
    var _fetchedResultsController: NSFetchedResultsController? = nil

    func controllerWillChangeContent(controller: NSFetchedResultsController) {
        self.tableView.beginUpdates()
    }

    func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
        switch type {
            case .Insert:
                self.tableView.insertSections(NSIndexSet(index: sectionIndex), withRowAnimation: .Fade)
            case .Delete:
                self.tableView.deleteSections(NSIndexSet(index: sectionIndex), withRowAnimation: .Fade)
            default:
                return
        }
    }

    func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
        switch type {
            case .Insert:
                tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Fade)
            case .Delete:
                tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)
            case .Update:
                self.configureCell(tableView.cellForRowAtIndexPath(indexPath!)!, atIndexPath: indexPath!)
            case .Move:
                tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)
                tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Fade)
        }
    }

    func controllerDidChangeContent(controller: NSFetchedResultsController) {
        self.tableView.endUpdates()
    }

    /*
     // Implementing the above methods to update the table view in response to individual changes may have performance implications if a large number of changes are made simultaneously. If this proves to be an issue, you can instead just implement controllerDidChangeContent: which notifies the delegate that all section and object changes have been processed.

     func controllerDidChangeContent(controller: NSFetchedResultsController) {
         // In the simplest, most efficient, case, reload the table view.
         self.tableView.reloadData()
     }
     */

}

//
//  DetailViewController.swift
//  Blog Reader
//
//  Created by zcdll on 16/1/24.
//  Copyright © 2016年 ZC. All rights reserved.
//

import UIKit

class DetailViewController: UIViewController {

    @IBOutlet weak var webview: UIWebView!

    var detailItem: AnyObject? {
        didSet {
            // Update the view.
            self.configureView()
        }
    }

    func configureView() {
        // Update the user interface for the detail item.
        if let detail = self.detailItem {
            if let postWebView = self.webview {

                postWebView.loadHTMLString(detail.valueForKey("content")!.description, baseURL: NSURL(string: "https://googleblog.blogspot.com/"))

            }
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.configureView()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

工程：27_Blog Reader