当app来到前台时如何刷新UIWebView？

Question

每当我的应用程序到达前台时,我想刷新UIWebView.我在ViewController.m中真正拥有的是一种检查互联网访问(hasInternet)和viewDidLoad的方法.

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

@synthesize webview;

-(BOOL)hasInternet{
    Reachability *reach = [Reachability reachabilityWithHostName:@"www.google.com"];
    NetworkStatus internetStats = [reach currentReachabilityStatus];

    if (internetStats == NotReachable) {
        UIAlertView *alertOne = [[UIAlertView alloc] initWithTitle:@"You're not connected to the internet." message:@"Please connect to the internet and restart the app." delegate:self cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
        [alertOne show];
    }

    return YES;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self hasInternet];
    [webView loadRequest: [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://warm-chamber-7399.herokuapp.com/"]] ];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

有关如何启用此功能的任何建议？它是在AppDelegate中还是在ViewController.m中创建另一个方法？

Answer 1

您应该UIApplicationWillEnterForegroundNotification在自己ViewController的viewDidLoad方法中注册一个,每当应用程序从后台返回时,您可以在注册通知的方法中执行任何操作.ViewController的viewWillAppear或viewDidAppear当应用程序回来,从后台到前台就不会被调用.

-(void)viewDidLoad{

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(doYourStuff)

    name:UIApplicationWillEnterForegroundNotification object:nil];
}

-(void)doYourStuff{

  [webview reload];
}

不要忘记取消注册您注册的通知.

-(void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

请注意,如果您注册了viewControllerfor,UIApplicationDidBecomeActiveNotification那么每次您的应用程序变为活动状态时都会调用您的方法,注册此通知是不合适的.