AppDelegate共有インスタンスのデリゲート

Question

    MyAppDelegate *appD;        
    appD = [UIApplication sharedApplication];

    if(appD.sw1.on)
        NSLog(@"It is ON");
    else
        NSLog(@"It is OFF");

.

コンパイル中にエラーを与えません。警告なしで実行されますが、機能しません。

問題が何であるか見てはいけません。

...

編集： OMGは、Delegateメソッドを呼び出したはずです：

appD = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];

.

Answer 1

I recommend you this method to share the app delegate: https://coderwall.com/p/z4h4uw?i=2&p=1&q=&t%5B%5D=%21%21mine&t%5B%5D=%21%21bookmarks

Answer 2

and instantiated an appDelegate …

No, you haven't instantiated anything, you've just declared a variable that can point to your app delegate. But you haven't assigned anything to that variable yet.

And instantiating another object would be wrong here since the app delegate instance already exists. You just have to reference the existing app delegate and assign it to your variable:

appD = (myAppDelegate *)[[UIApplication sharedApplication] delegate];

(Btw, you should follow the naming conventions. Class names should always begin with a capital letter.)