Initial commit

Author: Florian Kugler

Item.h

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+//
+//  Item.h
+//  NestedTodoList
+//
+//  Created by Chris Eidhof on 8/14/13.
+//  Copyright (c) 2013 Chris Eidhof. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+#import <CoreData/CoreData.h>
+
+@class Item;
+
+@interface Item : NSManagedObject
+
+@property (nonatomic, retain) NSString* title;
+@property (nonatomic, assign) NSNumber* order;
+@property (nonatomic, retain) Item* parent;
+@property (nonatomic, retain) NSSet* children;
+
++ (instancetype)insertItemWithTitle:(NSString*)title
+                             parent:(Item*)parent
+             inManagedObjectContext:(NSManagedObjectContext*)managedObjectContext;
+
+- (NSFetchedResultsController*)childrenFetchedResultsController;
+
+@end

Item.m

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+//
+//  Item.m
+//  NestedTodoList
+//
+//  Created by Chris Eidhof on 8/14/13.
+//  Copyright (c) 2013 Chris Eidhof. All rights reserved.
+//
+
+#import "Item.h"
+#import "Item.h"
+
+
+@implementation Item
+
+@dynamic title;
+@dynamic parent;
+@dynamic children;
+@dynamic order;
+
++ (instancetype)insertItemWithTitle:(NSString*)title
+                             parent:(Item*)parent
+             inManagedObjectContext:(NSManagedObjectContext *)managedObjectContext
+{
+    NSUInteger order = parent.numberOfChildren;
+    Item* item = [NSEntityDescription insertNewObjectForEntityForName:self.entityName
+                                               inManagedObjectContext:managedObjectContext];
+    item.title = title;
+    item.parent = parent;
+    item.order = @(order);
+    return item;
+}
+
++ (NSString*)entityName
+{
+    return @"Item";
+}
+
+- (NSUInteger)numberOfChildren
+{
+    return self.children.count;
+}
+
+- (NSFetchedResultsController*)childrenFetchedResultsController
+{
+    NSFetchRequest* request = [NSFetchRequest fetchRequestWithEntityName:[self.class entityName]];
+    request.predicate = [NSPredicate predicateWithFormat:@"parent = %@", self];
+    request.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"order" ascending:YES]];
+    return [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
+}
+
+- (void)prepareForDeletion
+{
+    if (self.parent.isDeleted) return;
+    
+    NSSet* siblings = self.parent.children;
+    NSPredicate* predicate = [NSPredicate predicateWithFormat:@"order > %@", self.order];
+    NSSet* itemsAfterSelf = [siblings filteredSetUsingPredicate:predicate];
+    [itemsAfterSelf enumerateObjectsUsingBlock:^(Item* sibling, BOOL* stop)
+    {
+        sibling.order = @(sibling.order.integerValue - 1);
+    }];
+}
+
+@end

NestedTodoList.xcodeproj/project.pbxproj

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+//
+//  AppDelegate.h
+//  NestedTodoList
+//
+//  Created by Chris Eidhof on 8/13/13.
+//  Copyright (c) 2013 Chris Eidhof. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+@class Store;
+@class PersistentStack;
+
+@interface AppDelegate : UIResponder <UIApplicationDelegate>
+
+@property (strong, nonatomic) UIWindow *window;
+
+@end

NestedTodoList/AppDelegate.h

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+//
+//  AppDelegate.m
+//  NestedTodoList
+//
+//  Created by Chris Eidhof on 8/13/13.
+//  Copyright (c) 2013 Chris Eidhof. All rights reserved.
+//
+
+#import "AppDelegate.h"
+#import "ItemViewController.h"
+#import "Store.h"
+#import "PersistentStack.h"
+
+@interface AppDelegate ()
+
+@property (nonatomic, strong) Store* store;
+@property (nonatomic, strong) PersistentStack* persistentStack;
+@end
+
+@implementation AppDelegate
+
+- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions
+{
+    UINavigationController* navigationController = (UINavigationController*) self.window.rootViewController;
+    ItemViewController* rootViewController = (ItemViewController*)navigationController.topViewController;
+    NSAssert([rootViewController isKindOfClass:[ItemViewController class]], @"Should have an item view controller");
+    self.persistentStack = [[PersistentStack alloc] initWithStoreURL:self.storeURL modelURL:self.modelURL];
+    self.store = [[Store alloc] init];
+    self.store.managedObjectContext = self.persistentStack.managedObjectContext;
+    rootViewController.parent = self.store.rootItem;
+    application.applicationSupportsShakeToEdit = YES;
+    return YES;
+}
+
+- (NSURL*)storeURL
+{
+    NSURL* documentsDirectory = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:NULL];
+    return [documentsDirectory URLByAppendingPathComponent:@"db.sqlite"];
+}
+
+- (NSURL*)modelURL
+{
+    return [[NSBundle mainBundle] URLForResource:@"NestedTodoList" withExtension:@"momd"];
+}
+
+- (void)applicationDidEnterBackground:(UIApplication *)application
+{
+    [self.store.managedObjectContext save:NULL];
+}
+
+
+@end

NestedTodoList/AppDelegate.m

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+//
+// Created by Chris Eidhof
+//
+
+
+#import <Foundation/Foundation.h>
+#import <CoreData/CoreData.h>
+
+@class NSFetchedResultsController;
+
+@protocol FetchedResultsControllerDataSourceDelegate
+
+- (void)configureCell:(id)cell withObject:(id)object;
+- (void)deleteObject:(id)object;
+
+@end
+
+
+
+@interface FetchedResultsControllerDataSource : NSObject <UITableViewDataSource, NSFetchedResultsControllerDelegate>
+
+@property (nonatomic, strong) NSFetchedResultsController* fetchedResultsController;
+@property (nonatomic, weak) id<FetchedResultsControllerDataSourceDelegate> delegate;
+@property (nonatomic, copy) NSString* reuseIdentifier;
+@property (nonatomic) BOOL paused;
+
+- (id)initWithTableView:(UITableView*)tableView;
+- (id)selectedItem;
+
+@end

NestedTodoList/[email protected]

@@ -0,0 +1,112 @@
+//
+// Created by Chris Eidhof
+//
+
+
+#import <CoreData/CoreData.h>
+#import "FetchedResultsControllerDataSource.h"
+
+
+@interface FetchedResultsControllerDataSource ()
+
+@property (nonatomic, strong) UITableView* tableView;
+
+@end
+
+@implementation FetchedResultsControllerDataSource
+
+- (id)initWithTableView:(UITableView*)tableView
+{
+    self = [super init];
+    if (self) {
+        self.tableView = tableView;
+        self.tableView.dataSource = self;
+    }
+    return self;
+}
+
+- (NSInteger)numberOfSectionsInTableView:(UITableView*)tableView
+{
+    return self.fetchedResultsController.sections.count;
+}
+
+- (NSInteger)tableView:(UITableView*)tableView numberOfRowsInSection:(NSInteger)sectionIndex
+{
+    id<NSFetchedResultsSectionInfo> section = self.fetchedResultsController.sections[sectionIndex];
+    return section.numberOfObjects;
+}
+
+- (UITableViewCell*)tableView:(UITableView*)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath
+{
+    id object = [self.fetchedResultsController objectAtIndexPath:indexPath];
+    id cell = [tableView dequeueReusableCellWithIdentifier:self.reuseIdentifier forIndexPath:indexPath];
+    [self.delegate configureCell:cell withObject:object];
+    return cell;
+}
+
+- (BOOL)tableView:(UITableView*)tableView canEditRowAtIndexPath:(NSIndexPath*)indexPath
+{
+    return YES;
+}
+
+- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
+    if (editingStyle == UITableViewCellEditingStyleDelete) {
+        [self.delegate deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];
+    }
+}
+
+#pragma mark NSFetchedResultsControllerDelegate
+
+- (void)controllerWillChangeContent:(NSFetchedResultsController*)controller
+{
+    [self.tableView beginUpdates];
+}
+
+- (void)controllerDidChangeContent:(NSFetchedResultsController*)controller
+{
+    [self.tableView endUpdates];
+}
+
+- (void)controller:(NSFetchedResultsController*)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath*)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath*)newIndexPath
+{
+    if (type == NSFetchedResultsChangeInsert) {
+        [self.tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
+    } else if (type == NSFetchedResultsChangeMove) {
+        [self.tableView moveRowAtIndexPath:indexPath toIndexPath:newIndexPath];
+    } else if (type == NSFetchedResultsChangeDelete) {
+        [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
+    } else {
+        NSAssert(NO,@"");
+    }
+}
+
+- (void)setFetchedResultsController:(NSFetchedResultsController*)fetchedResultsController
+{
+    NSAssert(_fetchedResultsController == nil, @"TODO: you can currently only assign this property once");
+    _fetchedResultsController = fetchedResultsController;
+    fetchedResultsController.delegate = self;
+    [fetchedResultsController performFetch:NULL];
+}
+
+
+- (id)selectedItem
+{
+    NSIndexPath* path = self.tableView.indexPathForSelectedRow;
+    return path ? [self.fetchedResultsController objectAtIndexPath:path] : nil;
+}
+
+
+- (void)setPaused:(BOOL)paused
+{
+    _paused = paused;
+    if (paused) {
+        self.fetchedResultsController.delegate = nil;
+    } else {
+        self.fetchedResultsController.delegate = self;
+        [self.fetchedResultsController performFetch:NULL];
+        [self.tableView reloadData];
+    }
+}
+
+
+@end

NestedTodoList/Default.png

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+//
+// Created by Chris Eidhof
+//
+
+
+#import <Foundation/Foundation.h>
+
+@class FetchedResultsControllerDataSource;
+@class Store;
+@class Item;
+
+
+@interface ItemViewController : UITableViewController
+
+@property (nonatomic, strong) Item* parent;
+
+@end