Web视图上的加载指示器

问题描述

我的应用程序以表格视图显示来自RSS提要的文章，然后当您选择一行时，打开一个Web视图控制器以显示该文章。我正在尝试添加加载指示器。如果选择一行，指示器将短暂显示，然后在页面完全加载之前消失。另外，如果我返回到表格视图并选择其他行，则加载指示符将永远不会显示。我正在使用一个名为SVProgressHUD的自定义加载指示器，该指示器在应用程序的其他位置都可以正常工作。我不认为这是问题所在。我在做什么错？

这是我的表格视图中的didSelectRowAtIndexPath方法：

 -（void）tableView：（UITableView *）tableView didSelectRowAtIndexPath：（NSIndexPath *）indexPath 
 {
 [[webViewController webView] loadRequest：[NSURLRequest requestWithURL：[NSURL URLWithString：@ about ：空白]]]; 
 
 [self.navigationController pushViewController：webViewController动画：是]； 
 
 //抓取所选项目
 RSSItem * entry = [[频道项目] objectAtIndex：[indexPath row]]; 
 
 //使用项目
的链接字符串构造URL NSURL * url = [NSURL URLWithString：[输入链接]]; 
 
 //构造带有该URL的请求对象
 NSURLRequest * req = [NSURLRequest requestWithURL：url]; 
 
 //将请求加载到Web视图中
 [[webViewController webView] loadRequest：req]; 
 webViewController.hackyURL =网址; 
} 
  

加载指示器从WebViewController的viewDidLoad中的这一行开始：

  [SVProgressHUD showWithStatus：@正在加载]; 
  

这是我的WebViewController。

  #import WebViewController.h 
 #import TUSafariActivity.h 
 #import SVProgressHUD.h 
 
 @implementation WebViewController 
 @synthesize webView = webView，hackyURL = hackyURL; 
 
-（void）loadView 
 {
 //创建一个与屏幕一样大的UIWebView实例
 CGRect screenFrame = [[UIScreen mainScreen] applicationFrame]; 
 UIWebView * wv = [[UIWebView alloc] initWithFrame：screenFrame]; 
 webView = wv; 
 NSLog（@％@，webView.request.URL）; 
 //告诉Web视图缩放Web内容以适合Webview的范围
 [wv setScalesPageToFit：YES]; 
 
 [self setView：wv]; 
} 
 
-（UIWebView *）webView 
 {
 return（UIWebView *）[self view]; 
} 
 
-（void）showMenu 
 {
 NSURL * urlToShare = hackyURL; 
 NSArray * activityItems = @ [urlToShare]; 
 TUSafariActivity * activity = [[TUSafariActivity alloc] init]; 
 
 __block UIActivityViewController * activityVC = [[UIActivityViewController alloc] initWithActivityItems：activityItems applicationActivities：@ [activity]]; 
 activityVC.excludedActivityTypes = @ [UIActivityTypeAssignToContact，UIActivityTypePostToWeibo，UIActivityTypeSaveToCameraRoll]; 
 
 [self presentViewController：activityVC动画：是完成：^ {activityVC.excludedActivityTypes = nil; activityVC = nil;}]; 
} 
 
-（void）toggleBars：（UITapGestureRecognizer *）gesture 
 {
 BOOL barsHidden = self.navigationController.navigationBar.hidden; 
 
 if（！barsHidden）
 {
 [[UIApplication sharedApplication] setStatusBarHidden：YES withAnimation：UIStatusBarAnimationSlide]; 
 [self hideTabBar：self.tabBarController]; 
} 
 else if（barsHidden）
 {
 [[UIApplication sharedApplication] setStatusBarHidden：NO withAnimation：UIStatusBarAnimationSlide]; 
 [self showTabBar：self.tabBarController]; 
} 
 
 [self.navigationController setNavigationBarHidden：！barsHidden animation：YES]; 
} 
 
-（void）viewDidLoad 
 {
 [super viewDidLoad]; 
 //从其笔尖加载视图后，执行任何其他设置。 
 
 [SVProgressHUD showWithStatus：@正在加载]; 
 
 UIBarButtonItem * systemAction = [[UIBarButtonItem alloc] initWithBarButtonSystemItem：UIBarButtonSystemItemAction target：self action：@selector（showMenu）]; 
 self.navigationItem.rightBarButtonItem = systemAction; 
 
 UITapGestureRecognizer * singleTap = [[UITapGestureRecognizer alloc] initWithTarget：self action：@selector（toggleBars :)]; 
 [webView addGestureRecognizer：singleTap]; 
 singleTap.delegate =自我; 
 
 // self.hidesBottomBarWhenPushed = YES; 
} 
 
-（布尔）gestureRecognizer：（UIGestureRecognizer *）gestureRecognizer应该可以同时识别WithGestureRecognizer：（UIGestureRecognizer *）otherGestureRecognizer 
 {
 return YES; 
} 
 
-（void）hideTabBar：（UITabBarController *）tabbarcontroller 
 {
 CGRect screenRect = [[UIScreen mainScreen] bounds]; 
 
 [UIView beginAnimations：nil context：NULL]; 
 [UIView setAnimationDuration：0.5]; 
 float fHeight = screenRect.size.height; 
 if（UIDeviceOrientationIsLandscape（[UIApplication sharedApplication] .statusBarOrientation））
 {
 fHeight = screenRect.size.width; 
} 
 
 for（UIView * tabbarcontroller.view.subviews中的视图）
 {
 if（[view isKindOfClass：[UITabBar class]]）
 {
 [view setFrame：CGRectMake（view.frame.origin.x，fHeight，view.frame.size.width，view.frame.size.height）]]； 
} 
其他
 {
 [view setFrame：CGRectMake（view.frame.origin.x，view.frame.origin.y，view.frame.size.width，fHeight ）]; 
 view.backgroundColor = [UIColor blackColor]; 
} 
} 
 [UIView commitAnimations]; 
} 
 
-（void）showTabBar：（UITabBarController *）tabbarcontroller 
 {
 CGRect screenRect = [[UIScreen mainScreen] bounds]; 
 float fHeight = screenRect.size.height-49.0; 
 
 if（UIDeviceOrientationIsLandscape（[UIApplication sharedApplication] .statusBarOrientation））
 {
 fHeight = screenRect.size.width-49.0; 
} 
 
 [UIView beginAnimations：nil context：NULL]; 
 [UIView setAnimationDuration：0.5]; 
 for（UIView * tabbarcontroller.view.subviews中的视图）
 {
 if（[view isKindOfClass：[UITabBar class]]）
 {
 [view setFrame： CGRectMake（view.frame.origin.x，fHeight，view.frame.size.width，view.frame.size.height）]; 
} 
其他
 {
 [view setFrame：CGRectMake（view.frame.origin.x，view.frame.origin.y，view.frame.size.width，fHeight ）]; 
} 
} 
 [UIView commitAnimations]; 
} 
 
-（void）webViewDidFinishLoad：（UIWebView *）webView 
 {
 //加载完成后停止活动指示器
 [SVProgressHUD关闭] ; 
} 
 
 @end 
  

解决方案

您应该使用网络视图的 delegate 功能

 -（void）webViewDidStartLoad：（UIWebView *）webView {
 // SHOW HUD 
} 
 
-（ void）webView：（UIWebView *）webView didFailLoadWithError：（NSError *）error {
 //杀死HUD 
} 
 
-（void）webViewDidFinishLoad：（UIWebView *）webView { 
 
 if（！webView.loading）{
 //杀死HUD 
} 
} 
  

在 webview 中通常会发生缓存，因此HUD可能不会显示很长时间，因为它将在第一次加载时显示。 p>

我希望它会对您有所帮助。

My app shows articles from an RSS feed in a table view then when you select a row, opens a web view controller to show the article. I'm trying to add a loading indicator. If I select a row, the indicator will show briefly and then disappear before the page is fully loaded. Also, if I go back to the table view and select a different row, the loading indicator never shows up. I'm using a custom loading indicator called SVProgressHUD and it works fine elsewhere in the app. I don't think that is the problem though. What am I doing wrong?

Here is my didSelectRowAtIndexPath method in my table view:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [[webViewController webView]loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"about:blank"]]];

    [self.navigationController pushViewController:webViewController animated:YES];

    // Grab the selected item
    RSSItem *entry = [[channel items]objectAtIndex:[indexPath row]];

    // Construct a URL with the link string of the item
    NSURL *url = [NSURL URLWithString:[entry link]];

    // Construct a request object with that URL
    NSURLRequest *req = [NSURLRequest requestWithURL:url];

    // Load the request into the web view
    [[webViewController webView]loadRequest:req];
    webViewController.hackyURL = url;
}

The loading indicator is started on this line in viewDidLoad of the WebViewController:

[SVProgressHUD showWithStatus:@"Loading"];

And here is my WebViewController.

#import "WebViewController.h"
#import "TUSafariActivity.h"
#import "SVProgressHUD.h"

@implementation WebViewController
@synthesize webView=webView, hackyURL=hackyURL;

- (void)loadView
{
    // Create an instance of UIWebView as large as the screen
    CGRect screenFrame = [[UIScreen mainScreen]applicationFrame];
    UIWebView *wv = [[UIWebView alloc]initWithFrame:screenFrame];
    webView = wv;
    NSLog(@"%@",webView.request.URL);
    // Tell web view to scale web content to fit within bounds of webview
    [wv setScalesPageToFit:YES];

    [self setView:wv];
}

- (UIWebView *)webView
{
    return (UIWebView *)[self view];
}

- (void) showMenu
{
    NSURL *urlToShare = hackyURL;
    NSArray *activityItems = @[urlToShare];
    TUSafariActivity *activity = [[TUSafariActivity alloc] init];

    __block UIActivityViewController *activityVC = [[UIActivityViewController alloc]initWithActivityItems:activityItems applicationActivities:@[activity]];
    activityVC.excludedActivityTypes = @[UIActivityTypeAssignToContact, UIActivityTypePostToWeibo, UIActivityTypeSaveToCameraRoll];

    [self presentViewController:activityVC animated:YES completion:^{activityVC.excludedActivityTypes = nil; activityVC = nil;}];
}

- (void)toggleBars:(UITapGestureRecognizer *)gesture
{
    BOOL barsHidden = self.navigationController.navigationBar.hidden;

    if (!barsHidden)
    {
        [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationSlide];
        [self hideTabBar:self.tabBarController];
    }
    else if (barsHidden)
    {
        [[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationSlide];
        [self showTabBar:self.tabBarController];
    }

    [self.navigationController setNavigationBarHidden:!barsHidden animated:YES];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    [SVProgressHUD showWithStatus:@"Loading"];

    UIBarButtonItem *systemAction = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:@selector(showMenu)];
    self.navigationItem.rightBarButtonItem = systemAction;

    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(toggleBars:)];
    [webView addGestureRecognizer:singleTap];
    singleTap.delegate = self;

    // self.hidesBottomBarWhenPushed = YES;
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

- (void) hideTabBar:(UITabBarController *) tabbarcontroller
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];
    float fHeight = screenRect.size.height;
    if(  UIDeviceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation) )
    {
        fHeight = screenRect.size.width;
    }

    for(UIView *view in tabbarcontroller.view.subviews)
    {
        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, fHeight, view.frame.size.width, view.frame.size.height)];
        }
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, fHeight)];
            view.backgroundColor = [UIColor blackColor];
        }
    }
    [UIView commitAnimations];
}

- (void) showTabBar:(UITabBarController *) tabbarcontroller
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    float fHeight = screenRect.size.height - 49.0;

    if(  UIDeviceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation) )
    {
        fHeight = screenRect.size.width - 49.0;
    }

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];
    for(UIView *view in tabbarcontroller.view.subviews)
    {
        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, fHeight, view.frame.size.width, view.frame.size.height)];
        }
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, fHeight)];
        }
    }
    [UIView commitAnimations];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    //stop the activity indicator when done loading
    [SVProgressHUD dismiss];
}

@end

解决方案

You should use the delegate functions of a webview see below

-(void)webViewDidStartLoad:(UIWebView *)webView{
   //SHOW HUD
}

-(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{
  //KILL HUD
}

-(void)webViewDidFinishLoad:(UIWebView *)webView{

    if(!webView.loading){
         //KILL HUD
    }
}

In webview normally caching happens, so HUD might not show for long as it will show for the first load.

I hope it will help you.

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