如何為iPhone刷新UIWebview？

Question

我有一個擁有UIWebView的iPhone應用程序。 在X小時后，用戶再次啟動應用程序，我發現即使頁面可能包含新內容，webview也會顯示相同的數據。 當用戶在X小時后第二次啟動應用程序時，如何自動讓UIWebView刷新頁面？

Answer 1

用於重新加載webView使用

[webView reload];

用於計算時差：

- (NSTimeInterval)timeIntervalSinceDate:(NSDate *)anotherDate

為計算X小時，請執行以下操作

添加這是viewDidLoad：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationEnteredBackground) name:UIApplicationDidEnterBackgroundNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationEnteredForeground) name:UIApplicationDidEnterForegroundNotification object:nil];

寫通知處理功能

 -(void)applicationEnteredBackground
 {
  //storing timestamp when user goes background 
  NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];
  [userDefaults setObject:[NSDate date] forKey:@"timeStamp"];
  [userDefaults synchronize];    
 }

 -(void)applicationEnteredForeground
 {
   NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];
   NSString *lastTimeOpened= [userDefaults objectForKey:@"timeStamp"];
   NSDateFormatter *formatter=[[NSDateFormatter alloc]init];
   //set formatter style as long
   if([[NSDate date] timeIntervalSinceDate:[formatter dateFromString:lastTimeOpened]] > X hours)
   {
     //reload your webview here.
   }
 }