Question

我知道这是一个非常常见的问题，我阅读了stackoverflow中提出的大部分问题，但仍然无法弄清楚如何从视图中删除uiactivityindicatorview。请在下面找到代码

@implementation FeedBackViewController
@synthesize m_activity,webView;

-(void)viewDidLoad{

    [super viewDidLoad];


    [webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://equinox.library.pitt.edu/limesurvey/index.php?sid=87435&lang=en"]]];


}

- (void)dealloc {
    [m_activity release];
    [webView release];
    [super dealloc];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    [m_activity stopAnimating];
    [m_activity removeFromSuperview];
    m_activity = nil;
}

- (void)webViewDidStartLoad:(UIWebView *)webView { 
NSLog(@"in webViewDidFinishLoad")    
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    m_activity.center = self.view.center;
    [self.view addSubview: m_activity];
    [m_activity startAnimating];
}

头文件

@interface FeedBackViewController : UIViewController<UIWebViewDelegate>{
    IBOutlet UIWebView *webView;        
    IBOutlet UIActivityIndicatorView *m_activity; 
}
@property (nonatomic, retain) IBOutlet UIWebView *webView;
@property (nonatomic, retain) UIActivityIndicatorView *m_activity;

另外，我已经检查过IB中的方框，说明在停止时隐藏。我将NSLog(@"in webViewDidFinishLoad")放在webViewFinishLoad方法中，似乎由于某种原因它没有触及该方法。和

NSLog(@"m_activity = %@",m_activity);

在viewDidLoad方法中，它在控制台中显示如下消息

> m_activity = <UIActivityIndicatorView:
> 0x4d3d920; frame = (150 79; 20 20);
> hidden = YES; opaque = NO; autoresize
> = RM+BM; layer = <CALayer: 0x4d35ce0>>

Answer 1

您的webViewDidFinishLoad函数可能未被调用。如果Web视图无法打开URL，则可能会发生这种情况。在任何情况下，您还应该实现webView:didFailLoadWithError:方法并在那里停止活动指示器。

-edit -

要从UIWebView接收事件，您需要将控制器设置为UIWebView的委托。仅实现UIWebViewDelegate是不够的。您可以通过更新viewDidLoad方法执行此操作，如下所示：

-(void)viewDidLoad{
 [super viewDidLoad];

 webView.delegate = self;
 [webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://equinox.library.pitt.edu/limesurvey/index.php?sid=87435&lang=en"]]];
}

Answer 2

您应该在代码中添加NSLog(@"in webViewDidFinishLoad")行，并观察控制台以查看代码是否符合这些要点。由于这是一个非常简单的例子，也许m_activity没有连接到实际的对象？在将viewDidLoad添加到viewDidLoad的末尾时，尝试查看是否获得地址或null：

NSLog(@"m_activity = %@",m_activity);

iphone - uiactivityindicatorview并不隐藏

2 个答案: