objective-c - "no known class method for selector"困惑

Question

可能是菜鸟问题，但就是这样。我让我的 AppDelegate 从“application didFinishLaunchingWithOptions”中的文件实例化一个新字典。我有一个 addViewController ，我想传递一个新对象以添加到 AppDelegate 的字典中，以便稍后保存到磁盘。这是我所掌握的一些片段。

//
//  AppDelegate.m
//  PersonLibraryiOS
//
//  Created by Joey on 11/7/12.
//  Copyright (c) 2012 Joey. All rights reserved.
//

#import "AppDelegate.h"
#import "AddViewController.h"
#import "Person.h"
@implementation AppDelegate
@synthesize PersonDict;

-(void)addtoDict:(Person *)newPerson
{
    [PersonDict setObject:@"newPerson" forKey:[newPerson name]];
}



- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    return YES;
    PersonDict = [NSMutableDictionary dictionaryWithContentsOfFile:@"diskDict"];

和AddViewController:

//
//  AddViewController.m
//  personLibraryiOS
//
//  Created by Joey on 11/8/12.
//  Copyright (c) 2012 Joey. All rights reserved.
//

#import "AddViewController.h"
#import "TableViewController.h"
#import "person.h"
#import "AppDelegate.h"

@implementation AddViewController
@synthesize nameLabel;
@synthesize ageLabel;
@synthesize heightLabel;
@synthesize weightLabel;
@synthesize hairColorLabel;
@synthesize eyeColorLabel;


- (IBAction)saveButton:(id)sender
{
    person *newperson = [[person alloc]init];

    newperson.name = [nameLabel text];
    newperson.age = [ageLabel text];
    newperson.height = [heightLabel text];
    newperson.weight = [weightLabel text];
    newperson.hairColor = [hairColorLabel text];
    newperson.eyeColor = [eyeColorLabel text];



    [AppDelegate addtoDict:newperson];  <---- the error is here

     }

我知道这可能是基本的，但我真的很困惑。我正在 addViewController 中导入 AppDelegate.h 文件，因此它应该了解有关 AppDelegate 方法的所有信息。

谢谢大家。

Answer 1

AppDelegate 是一个类。您可能想要与充当应用程序委托(delegate)的类的特定实例进行通信，该实例是 [[UIApplication sharedApplication] delegate]。类与其实例不可互换。