iOS中讓Settings Bundle中的變化立即在App中反應出來的兩種方法

iOS中讓Settings Bundle中的變化立即在App中反應出來的兩種方法

為了能夠在Settings Bundle中的變化在進入App後能夠立即反應出來,我們必須牢牢守住一個位置:即當App從後台進入前台時.

我們有2種辦法在該時刻做一些讀取的操作,一種是在- (void)applicationWillEnterForeground:(UIApplication *)application方法中處理,一種是註冊UIApplicationWillEnterForegroundNotification通知.

我們分別來看一下,首先是applicationWillEnterForeground方法,很簡單,在其中做我們想要的:

- (void)applicationWillEnterForeground:(UIApplication *)application {    [_viewController refreshFields];}

然後是UIApplicationWillEnterForegroundNotification通知,我們可以在視圖的某個進入方法裡調用:

-(void)viewDidAppear:(BOOL)animated{    [super viewDidAppear:animated];    [self refreshFields];    UIApplication *app = [UIApplication sharedApplication];    [[NSNotificationCenter defaultCenter]addObserver:self selector:                                    @selector(applicationWillEnterFg:) name:                                    UIApplicationWillEnterForegroundNotification object:app];}

最後是回調方法的實現:

-(void)applicationWillEnterFg:(NSNotification*)notification{    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];    [defaults synchronize];    [self refreshFields];}