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

您应该在UIApplicationWillEnterForegroundNotification的{{1}}方法中注册ViewController，当应用从后台返回时，您可以在注册通知的方法中执行任何操作。当应用从后台返回到前台时，viewDidLoad的{{1}}或ViewController将不会被调用。

viewWillAppear

不要忘记取消注册您注册的通知。

viewDidAppear

注意如果您为-(void)viewDidLoad{ [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(doYourStuff) name:UIApplicationWillEnterForegroundNotification object:nil]; } -(void)doYourStuff{ [webview reload]; }注册-(void)dealloc { [[NSNotificationCenter defaultCenter] removeObserver:self]; }，那么每次您的应用变为有效时都会调用您的方法，注册此通知是不合适的。< / p>

Answer 2

注册UIApplicationDidBecomeActiveNotification或UIApplicationWillEnterForegroundNotification。

当app来到前台时如何刷新UIWebView？

2 个答案: