Note_Master-Detail Application(iOS template)_05_ YJYMasterViewController.m

//  YJYMasterViewController.m

#import "YJYMasterViewController.h"

#import "YJYDetailViewController.h"

 /*

@interface:接口,提供类的公共描述,接口里面包含了使用该类的所需信息,编译此部分后,就能够使用该的对象及调用类方法。

@implementation:实现,告诉编译器如何让该类工作,实现了接口中声明的方法。

代码分为接口和实现两部分,

接口部分包含:@interface指令、公共struct定义、enum常量、@defines和extern全局变量等。

实现部分包含:@implementation指令、全局变量的定义、私有struct等。

#import:导入头文件:头文件包含元素声明(如,结构体、符号常量、函数原型等),#import同c语言中的#include类似,它们的区别在于,在c语言中,通常使用#ifdef命令来避免一个头文件包含另一个文件,而#import可保证头文件只被包含一次。

带尖括号语句用来导入系统头文件(只读),带引号的语句用来导入项目本地头文件(可读)。

*/

@interface YJYMasterViewController ()

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath;

@end

@implementation YJYMasterViewController

 /*

当.nib文件被加载的时候,会发送一个awakeFromNib的消息到.nib文件中的每个对象,每个对象都可以定义自己的 awakeFromNib函数来响应这个消息,

执行一些必要的操作。也就是说通过nib文件创建view对象是执行awakeFromNib

*/

- (void)awakeFromNib

{

    self.clearsSelectionOnViewWillAppear = NO;

    self.contentSizeForViewInPopover = CGSizeMake(320.0, 600.0);

    [superawakeFromNib];

}

//当view对象被加载到内存是就会执行viewDidLoad,所以不管通过nib文件还是代码的方式创建对象都会执行viewDidLoad

- (void)viewDidLoad

{//释放视图资源

    NSLog(@"viewDidLoad() begin...");

    [super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

    self.navigationItem.leftBarButtonItem = self.editButtonItem;

    UIBarButtonItem *addButton = [[UIBarButtonItemalloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAddtarget:selfaction:@selector(insertNewObject:)];

    self.navigationItem.rightBarButtonItem = addButton;

    self.detailViewController = (YJYDetailViewController *)[[self.splitViewController.viewControllerslastObject] topViewController];

    NSLog(@"viewDidLoad() over...");

}

- (void)didReceiveMemoryWarning

{

    NSLog(@"didReceiveMemoryWarning() begin...over");

    [superdidReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

- (void)insertNewObject:(id)sender

{

    NSLog(@"insertNewObject() begin...");

    NSManagedObjectContext *context = [self.fetchedResultsControllermanagedObjectContext];

    NSEntityDescription *entity = [[self.fetchedResultsControllerfetchRequest] entity];

    NSManagedObject *newManagedObject = [NSEntityDescriptioninsertNewObjectForEntityForName:[entity name] inManagedObjectContext:context];

    

    // If appropriate, configure the new managed object.

    // Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the template.

    [newManagedObject setValue:[NSDate date] forKey:@"timeStamp"];

    

    // Save the context.

    NSError *error = nil;

    if (![context save:&error]) {

         // 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. 

        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);

        abort();

    }

    

    NSLog(@"insertNewObject() over...");

}

#pragma mark - Table View

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

{

    NSLog(@"numberOfSectionsInTableView being...over");

    return [[self.fetchedResultsControllersections] count];

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

{

    NSLog(@"tableView numberOfRowsInSection() beging...");

    id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];

    NSLog(@"tableView numberOfRowsInSection() over...");

    return [sectionInfo numberOfObjects];

}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    NSLog(@"tableView cellForRowAtIndexPath() beging...");

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"forIndexPath:indexPath];

    [self configureCell:cell atIndexPath:indexPath];

    NSLog(@"tableView cellForRowAtIndexPath() over...");

    return cell;

}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath

{//该方法控制master区的可编辑(删除)操作

    // Return NO if you do not want the specified item to be editable.

    return YES;

}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath

{

    if (editingStyle == UITableViewCellEditingStyleDelete) {

        NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];

        [context deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];

        

        NSError *error = nil;

        if (![context save:&error]) {

             // 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. 

            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);

            abort();

        }

    }   

}

- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath

{

    // The table view should not be re-orderable.

    returnYES;

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

    NSManagedObject *object = [[self fetchedResultsController] objectAtIndexPath:indexPath];

    self.detailViewController.detailItem = object;

}

#pragma mark - Fetched results controller

- (NSFetchedResultsController *)fetchedResultsController

{

    if (_fetchedResultsController != nil) {

        return_fetchedResultsController;

    }

    

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

    // Edit the entity name as appropriate.

    NSEntityDescription *entity = [NSEntityDescriptionentityForName:@"Event"inManagedObjectContext:self.managedObjectContext];

    [fetchRequest setEntity:entity];

    

    // Set the batch size to a suitable number.

    [fetchRequest setFetchBatchSize:20];

    

    // Edit the sort key as appropriate.

    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];

    NSArray *sortDescriptors = @[sortDescriptor];

    

    [fetchRequest setSortDescriptors:sortDescriptors];

    

    // Edit the section name key path and cache name if appropriate.

    // nil for section name key path means "no sections".

    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsControlleralloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContextsectionNameKeyPath:nilcacheName:@"Master"];

    aFetchedResultsController.delegate = self;

    self.fetchedResultsController = aFetchedResultsController;

    

NSError *error = nil;

if (![self.fetchedResultsControllerperformFetch:&error]) {

    // 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. 

    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);

    abort();

}

    

    return_fetchedResultsController;

}    

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller

{

    [self.tableViewbeginUpdates];

}

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo

           atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type

{

    switch(type) {

        caseNSFetchedResultsChangeInsert:

            [self.tableViewinsertSections:[NSIndexSetindexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];

            break;

            

        caseNSFetchedResultsChangeDelete:

            [self.tableViewdeleteSections:[NSIndexSetindexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];

            break;

    }

}

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject

       atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type

      newIndexPath:(NSIndexPath *)newIndexPath

{

    UITableView *tableView = self.tableView;

    

    switch(type) {

        caseNSFetchedResultsChangeInsert:

            [tableView insertRowsAtIndexPaths:@[newIndexPath]withRowAnimation:UITableViewRowAnimationFade];

            break;

            

        caseNSFetchedResultsChangeDelete:

            [tableView deleteRowsAtIndexPaths:@[indexPath]withRowAnimation:UITableViewRowAnimationFade];

            break;

            

        caseNSFetchedResultsChangeUpdate:

            [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];

            break;

            

        caseNSFetchedResultsChangeMove:

            [tableView deleteRowsAtIndexPaths:@[indexPath]withRowAnimation:UITableViewRowAnimationFade];

            [tableView insertRowsAtIndexPaths:@[newIndexPath]withRowAnimation:UITableViewRowAnimationFade];

            break;

    }

}

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller

{

    [self.tableViewendUpdates];

}

/*

// 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. 

 

 - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller

{

    // In the simplest, most efficient, case, reload the table view.

    [self.tableView reloadData];

}

 */

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath

{

    NSLog(@"configureCell atIndexPath() begin...");

    

    NSManagedObject *object = [self.fetchedResultsController objectAtIndexPath:indexPath];

    cell.textLabel.text = [[object valueForKey:@"timeStamp"] description];

    NSLog(@"configureCell atIndexPath() over...");

}

@end

原文地址:https://www.cnblogs.com/allearner/p/3623110.html