ios - 将数据从一个 View 传递到另一个 View

Question

我正在尝试将数据从一个 Controller 传递到另一个 Controller (不执行任何类型的动画或 segue)以使用数组填充表。填充表格不是问题，因为我已经能够做到这一点，但事实证明，使用表格 View 将数据发送到 Controller 是不可能的。

在过去的 4 天里，我一直在努力弄清楚如何做到这一点。我已经阅读了大量有用的帖子，包括:Passing Data between View Controllers ，绝对没有运气。我对 iOS 开发还很陌生，所以也许我完全忽略了一些应该很简单的东西。

我正在为侧边栏使用 SWRevealViewController。

WebAppViewController.m

- (void)webViewDidFinishLoad:(UIWebView *)webView
{

NSString *html = [webView stringByEvaluatingJavaScriptFromString:
                  @"document.getElementById('json-ios').innerHTML"];
NSData *jsonData = [html dataUsingEncoding:NSUTF8StringEncoding];
NSError *e;
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:nil error:&e];

NSArray *jsonArray = [dict objectForKey:@"results"];

// This is where I would like to pass jsonArray to my sidebar to populate a table (SidebarViewController) each time the page loads
.....

Answer 1

尝试使用 NSNotification 或 Singleton

NS通知:

@implementation TestClass

- (void) dealloc
{
    // If you don't remove yourself as an observer, the Notification Center
    // will continue to try and send notification objects to the deallocated
    // object.
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [super dealloc];
}

- (id) init
{
    self = [super init];
    if (!self) return nil;

    // Add this instance of TestClass as an observer of the TestNotification.
    // We tell the notification center to inform us of "TestNotification"
    // notifications using the receiveTestNotification: selector. By
    // specifying object:nil, we tell the notification center that we are not
    // interested in who posted the notification. If you provided an actual
    // object rather than nil, the notification center will only notify you
    // when the notification was posted by that particular object.

    [[NSNotificationCenter defaultCenter] addObserver:self
        selector:@selector(receiveTestNotification:) 
        name:@"TestNotification"
        object:nil];

    return self;
}

- (void) receiveTestNotification:(NSNotification *) notification
{
    // [notification name] should always be @"TestNotification"
    // unless you use this method for observation of other notifications
    // as well.

    if ([[notification name] isEqualToString:@"TestNotification"])
        NSLog (@"Successfully received the test notification!");
}

@end

...另一个类(class)的其他地方...

- (void) someMethod
{

    // All instances of TestClass will be notified
    [[NSNotificationCenter defaultCenter] 
        postNotificationName:@"TestNotification" 
        object:self];

}

source

单例:

创建单例的标准方法就像...

单例.h

@interface MySingleton : NSObject

+ (MySingleton*)sharedInstance;

@end

单例.m

#import "MySingleton.h"

@implementation MySingleton

#pragma mark - singleton method

+ (MySingleton*)sharedInstance
{
    static dispatch_once_t predicate = 0;
    __strong static id sharedObject = nil;
    //static id sharedObject = nil;  //if you're not using ARC
    dispatch_once(&predicate, ^{
        sharedObject = [[self alloc] init];
        //sharedObject = [[[self alloc] init] retain]; // if you're not using ARC
    });
    return sharedObject;
}

@end

source

P.S.单例不可能不工作。

单例就像一个静态对象。你会想在这里保存数据，整个应用程序都可以访问这些数据，而无需对代码进行太多更改。(它就像一个全局对象)而 NSNotification 是 self 解释和谷歌搜索