I am developing an app in Xcode but am having trouble with one part.
Basicly on the main app page, there is a small section that contains a web view. Everytime I change to another view controller and back, i see it flicker and reload. Is there a way to prevent it from reloading every time i open the view? instead just reloading every time I open the app.
This is the code:
NSURL *webUrl = [NSURL URLWithString:#"myurl.com"];
NSURLRequest *webrequestUrl = [NSURLRequest requestWithURL:webUrl];
[webView loadRequest:webrequestUrl];
webView.scrollView.scrollEnabled = NO;
webView.scrollView.bounces = NO;
Your webview is reloading every time you go to that screen is probably because you added it to either viewDidAppear: or viewWillAppear.
Add your block of code to the viewDidLoad method so it only gets executed when the view is loaded (aka when it's shown for the first time).
- (void)viewDidLoad:(BOOL)animated {
NSURL *webUrl = [NSURL URLWithString:#"myurl.com"];
NSURLRequest *webrequestUrl = [NSURLRequest requestWithURL:webUrl];
[webView loadRequest:webrequestUrl];
webView.scrollView.scrollEnabled = NO;
webView.scrollView.bounces = NO;
}
Edit: Oh by going to another view and back you meant going back on the navigation stack (or switching the navigation stack). In that case, you can keep a strong reference to your view controller with the webview and reuse it. Though I wouldn't suggest it doing it this was, unless that screen is the most important screen of your application.
Hope you are having your logic in other than the method
- (void)viewDidLoad
move your code to - viewDidLoad
even if your are having trouble then pass the preloaded UIWebView when ever you are navigating.
Related
I m just trying to fix all the contents of html according to the device screen.
I have to put html data at proper place for iPhone & iPad in webview.
Please help me!!!
I am going to assume that this question is a very basic one.
Suppose that you have placed a UIWebView in a view in your storyboard, and you have set layout constraints so that the UIWebView fills the view.
Then
Add an IBOutlet to your view controller, and connect it to the web view.
In the view controllers viewDidLoad: method, tell the web view what to display. Here is an example:
-(void)viewDidLoad {
[super viewDidLoad];
NSURL* url = [NSURL URLWithString:#"http://www.apple.com"];
NSURLRequest* r = [NSURLRequest requestWithURL:url];
[_webView loadRequest:r];
}
This loadRequest: call is asynchronous, meaning that the page may not show up immediately.
If this is not answering your question, please add more information.
Before I present my issue, I want to mention that I tried looking for solutions here and here.
I am creating a hybrid application which uses native UIWebView for rendering the responsive designed web application. Following is the issue description :
1. I have a UITabBarController.
2. Each of the tab has a UIWebView.
3. I have to preload all tabs.
4. I am showing a UIActivityIndicator till the content loads on the first tab.
5. White screen appears for about 8-10 seconds and then the content starts to appear.
I will be happy to see this time become 2-4 seconds.
Following is my implementation :
[self performSelectorOnMainThread:#selector(loadAllTabs) withObject:nil waitUntilDone:YES];
-(void) loadAllTabs
{
for(UIViewController * viewController in self.viewControllers){
if(![[NSUserDefaults standardUserDefaults]boolForKey:#"isSessionExpired"])
{
if((int)[self.viewControllers indexOfObject:viewController] != 4)
{
viewController.tabBarItem.tag = (int)[[self viewControllers] indexOfObject:viewController];
[viewController view];
}
}
}
}
In WebView controller's viewDidLoad I have :
[_tgWebView loadRequest:[NSURLRequest requestWithURL:homeURL]];
I was looking forward to suppressesIncrementalRendering, but since I am preloading all tabs, this does not work.
Since my app supports iOS 7+, thus WKWebView can't be applied here.
I also thought of increasing the launch image duration but learned that is won't be a good practice.
Can this be implemented using GCD?
Please bring out the pitfalls in my implementations so that my application makes better performance.
First, have UIWebView on each tab hidden until it has finished loading, then show it. Underneath the UIWebView you can have some placeholder image to describe it loading. Then using the webViewDidFinishLoad delegate method show the web view when it has finished loading. This approach will be non blocking.
- (void)webViewDidFinishLoad:(UIWebView *)webview
{
if (webview.isLoading)
return;
else
webView.hidden = false;
}
Second, preload the first tab then load the subsequent tabs while displaying the first. You can do that by placing the following code in the first tabs viewDidLoad method:
// Preload the subsquent tabs
for (UIViewController *aVC in self.tabBarController.viewControllers)
if ([aVC respondsToSelector:#selector(view)] && aVC != self)
aVC.view;
This way, the additional tabs web views are loaded in the background in a non blocking manner. You could combine it with hiding the web views while loading in case the user navigates to the additional tabs before their pages load.
I tested this with three tabs and it worked nicely.
So the first view controller could look something like this:
#implementation FirstViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Load the website
[self loadWebView];
// Preload the subsquent tabs
for (UIViewController *aVC in self.tabBarController.viewControllers)
if ([aVC respondsToSelector:#selector(view)] && aVC != self)
aVC.view;
}
-(void)loadWebView
{
// Create Request
NSURL *url = [NSURL URLWithString:#"http://anandTech.com"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
// Load the page
[webView loadRequest:request];
}
- (void)webViewDidFinishLoad:(UIWebView *)webview
{
if (webview.isLoading)
return;
else
webView.hidden = false;
}
EDIT:
Removed GDC as it was crashing when the views had WebViews
This post made my day. I am now using NSNotificationCenter for this.
It's hard to identify the where the problem is directly.
First, I suggest that you check your network connection by loading the page on a desktop machine on the same Wifi to see if it is your server that is too slow.
Also you can load your pages one by one instead of load all pages concurrently, since multiple HTTP request are not processed in a FIFO sequence, they may be processed out of order, and your page may need all resource to be loaded before displaying.
Do you control the web page your self? You can use safari inspector to inspect your web page to see where is the time spent, is it resource loading, javascript processing or rendering.
If I have a UIWebView with mediaPlaybackRequiresUserAction = YES, then later in my app create a new UIWebView and set mediaPlaybackRequiresUserAction = NO on it, it also changes the value of that property on the first instance.
e.g. I have a UIWebView and then present a second UIWebView modally (for an ad), changing mediaPlaybackRequiresUserAction on the modal webView affects the presenting UIWebView.
Any ideas why this is? Are UIWebViews all backed by a single instance?
Link to sample project here.
not sure your app purpose, just try this way:
- (IBAction)unwind:(UIStoryboardSegue *)unwindSegue
{
[self TS_updateLabel];
[[self webView] setMediaPlaybackRequiresUserAction:YES];
[self TS_reloadWebView];
}
....
in method TS_reloadWebView
if (self.webView.isLoading) {
[self.webView stopLoading];
}
[self.webView loadHTMLString:htmlString baseURL:baseURL];
I guess it also is UIWebView bug .... but now this way maybe can solve your problem.
I have an app where on the very last UIViewController there is a UIWebView... the user navigates through the app and at the very end they can transition (modal) to the final UIViewController with a UIWebView... in it's viewDidLoad I have the UIWebView load the page.
The problem is it takes about 8 seconds to load this page and that annoys users.
How can I load the UIWebView way ahead of time (like when the app is first launched!) if that UIViewController hasn't even been presented yet?
I had your same problem for UIWebView inside a UIPageViewController and I found a better solution.
If you are in FirstViewController and you have your webView in your SecondViewController put the loadHTMLString or loadRequest method in the viewDidLoad of your SecondViewController and call [secondViewController.view layoutSubviews] for start loading in your FirstViewController.
Ex:
FirstViewController
-(void)viewDidLoad{
[super viewDidLoad];
// _secondViewController -> An instance of SecondVieController
[_secondViewController.view layoutSubviews];
}
SecondViewController
-(void)viewDidLoad{
[super viewDidLoad];
NSURL *url =[NSURL URLWithString:#"http://www.google.it"];
NSURLRequest *request =[NSURLRequest requestWithURL:url];
[self.webView loadRequest:request];
}
What u can do is, load the html string
NSString *htmlFile = [[NSBundle mainBundle] pathForResource:self.path ofType:#"htm"];
NSError * error;
NSString* htmlString = [NSString stringWithContentsOfFile:htmlFile encoding:NSUTF8StringEncoding error:&error];
and when u display the webView load this content in your webView
[self.webView loadHTMLString:htmlString baseURL:[[NSBundle mainBundle] bundleURL]];
then your webview need only render your content and doesn't load the data
/// In Swift 2.0
do{
let path = NSBundle.mainBundle().pathForResource("theName", ofType: "html")!
let html = try String(contentsOfFile: path, encoding: NSUTF8StringEncoding)
webView.loadHTMLString(html, baseURL: nil)
}catch{
print("Error is happend")
}
Note: It works the same way for WKWebView
Not sure how much work you want to do for this but I think you could cache/store the data from the URL in something like a NSDictionary, or something similar, using [NSUserDefaults standardUserDefaults] and use that information before actually loading the page.
So, load the first time you use it, after it has been seen then store the data using NSUserDefaults. Next time you go to this page, load from the NSUserDefaults first and call the URL/API in the back ground then update NSUserDefaults with this new data.
If you are requesting or pulling specific information each time, then I don't think this will work. If that is your case, you can probably try loading the data/website in an earlier view controller (probably one that takes the user a while to navigate to) and then send that data to the webview. Something like delegate/protocol or maybe even NSNotificationCenter. Hope this helps.
UIWebView is very tricky object. Simple answer would be: no you can't.
UIWebView won't load a document or an URL if it is not in views hierarchy.
Don't try doing it in different thread/queue either.
What you can do is to add UIWebView to the views hierarchy at the very beginning (as you've mentioned) and then pass it to the last view controller with preloaded data. This may work, but it's not an elegant way.
Side questions is: why does it take 8 secs to load a page? Maybe you can download the content of this page earlier? Is it static or dynamic?
I have a UIViewController with a UIWebView where I'm placing a PDF.
The issue I'm facing is when I click on a table cell to show the PDF it does not show the first time however if i go back to the table and click on the cell again it appears.
I call the PDF to get loaded using the following:
if ([indexPath row] == 2)
{
NSString *path = [[NSBundle mainBundle] pathForResource:#"myFirstPdf" ofType:#"pdf"];
NSURL *url = [NSURL fileURLWithPath:path];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[webViewVC.webView loadRequest:request];
webViewVC.parent = _parent;
[_parent pushViewController:webViewVC];
}
The webViewVC itself I allocate using an initWithNib which has the UIWebView - nothing fancy there, simply a UIWebView with a IBOutlet.
Any ideas?
I think you should try 2 things:
(1) First, try loading the PDF from the web view controller. This is really the standard way to do this, rather than doing a load request for a web view that is not even on screen yet. All outlets are guaranteed to be loaded only in viewDidLoad of the controller.
(2) Second, try making use of the UIWebViewDelegate. For example, you could call setNeedsDisplay on the web view once loading is finished.
My idea : the first time you try the action your "webViewVC" hasn't been loaded yet, so webViewVC.webView is nil
the second time as you have displayed the webViewVC in your first attempt, it has been loaded, so webViewVC.webView isn't nil;
create a property on your webViewVC where you will set your request
and on your webViewVC viewWillAppear method do your [self.webView loadRequest:self.request];