I have one webview in my view controller that I want to use as a reader. How can I switch between multiple (x)html files in this webview? I retrieve them one by one with the following code:
apiClient.getData(forFile: file) { (data, error) in
if let error = error {
//show error
return
}
if let data = data {
self.data = data
self.webView.load(data, mimeType: mimeType, textEncodingName: "utf-8", baseURL: URL(string: "")!)
}
}
Right now When a user scrolls (horizontal) through the pages of an epub and transitions from one file to another, there is a short loading time (because it is retrieving the next xhtml from the server).
Right now, it is a jarring experience, preventing the user from scrolling forward. When the next file is loaded, the page jumps to the new one.
Related
This may sound silly... but is there any way to embed all videos in a directory to a webpage? I'm hosting some videos on my website but right now you have to manually browse the directory and just click a link to a video.
I know I can just embed those videos to a html page but is there any way to make it adapt automatically when I add new videos?
How you do this will depend on how you are building your server code and web page code, but the example below which is node and angular based does exactly what you are asking:
// GET: route to return list of upload videos
router.get('/video_list', function(req, res) {
//Log the request details
console.log(req.body);
// Get the path for the uploaded_video directory
var _p;
_p = path.resolve(__dirname, 'public', 'uploaded_videos');
//Find all the files in the diectory and add to a JSON list to return
var resp = [];
fs.readdir(_p, function(err, list) {
//Check if the list is undefined or empty first and if so just return
if ( typeof list == 'undefined' || !list ) {
return;
}
for (var i = list.length - 1; i >= 0; i--) {
// For each file in the directory add an id and filename to the response
resp.push(
{"index": i,
"file_name": list[i]}
);
}
// Set the response to be sent
res.json(resp);
});
});
This code is old in web years (i.e. about 3 years old) so the way node handles routes etc is likely different now but the concepts remains the same, regardless of language:
go to the video directory
get the lit of video files in it
build them into a JSON response and send them to the browser
browser extracts and displays the list
The browser code corresponding to the above server code in this case is:
$scope.videoList = [];
// Get the video list from the Colab Server
GetUploadedVideosFactory.getVideoList().then(function(data) {
// Note: should really do some type checking etc here on the returned value
console.dir(data.data);
$scope.videoList = data.data;
});
You may find some way to automatically generate a web page index from a directory, but the type of approach above will likely give you more control - you can exclude certain file names types etc quite easily, for example.
The full source is available here: https://github.com/mickod/ColabServer
Im creating a pdf file out of html content in swift 3.0:
/**
*
*/
func exportHtmlContentToPDF(HTMLContent: String, filePath: String) {
// let webView = UIWebView(frame: CGRect(x: 0, y: 0, width: 694, height: 603));
// webView.loadHTMLString(HTMLContent, baseURL: nil);
let pdfPrinter = PDFPrinter();
let printFormatter = UIMarkupTextPrintFormatter(markupText: HTMLContent);
// let printFormatter = webView.viewPrintFormatter();
pdfPrinter.addPrintFormatter(printFormatter, startingAtPageAt: 0);
let pdfData = self.drawPDFUsingPrintPageRenderer(printPageRenderer: pdfPrinter);
pdfData?.write(toFile: filePath, atomically: true);
}
/**
*
*/
func drawPDFUsingPrintPageRenderer(printPageRenderer: UIPrintPageRenderer) -> NSData! {
let data = NSMutableData();
UIGraphicsBeginPDFContextToData(data, CGRect.zero, nil);
printPageRenderer.prepare(forDrawingPages: NSMakeRange(0, printPageRenderer.numberOfPages));
let bounds = UIGraphicsGetPDFContextBounds();
for i in 0...(printPageRenderer.numberOfPages - 1) {
UIGraphicsBeginPDFPage();
printPageRenderer.drawPage(at: i, in: bounds);
}
UIGraphicsEndPDFContext();
return data;
}
Everything is rendered fine except my base64 encoded images. The HTML content itself in a webview or inside safari or chrome browser is presented correctly and is showing all images correctly. But the images are never rendered into the pdf.
Why are the images not rendered and how can I get them to be rendered?
This happens because WebKit first parses the HTML into a DOM, and renders content on multiple event loop cycles. You therefore need to wait for not just the page DOM to be ready but for the resource loading to be complete. As you also suggest, you need to refactor your code such that the webview gets loaded first, and you only then export its contents.
To determine the correct time to fire the export, you can observe for the state of the DOM document in the web view. There are multiple ways to do this, but the most readable option I find is a port of an answer to a related Objective-C question: in your UIWebViewDelegate implementation, implement webViewDidFinishLoad in the following way to monitor document.readyState:
func webViewDidFinishLoad(_ webView: UIWebView) {
guard let readyState = webView.stringByEvaluatingJavaScript(from: "document.readyState"),
readyState == "complete" else
{
// document not yet parsed, or resources not yet loaded.
return
}
// This is the last webViewDidFinishLoad call --> export.
//
// There is a problem with this method if you have JS code loading more content:
// in that case -webViewDidFinishLoad can get called again still after document.readyState has already been in state 'complete' once or more.
self.exportHtmlContentToPDF(…)
}
I found the solution!
The export to PDF happens before the rendering process is finished. If you put in a very small picture it is showing up in the PDF. If the picture is too big the rendering process takes too much time but the PDF export isnt waiting for the rendering to finish.
So what I did to make it work is the following:
Before I export to PDF I show the Result of the HTML in a WebView. The WebView is rendering everything correctly and now when I press on export to PDF the PDF is showing up correctly with all images inside.
So I guess this is a huge lag that there is no way to tell the PDF Exporter to wait for the rendering process to finish.
I am trying to get a code that is sent to me in the title element of a web view. I need to send an initial request and display that view so that the user can input a password, then the response to that will be the view that I want with the code in the title element. Is there a way to get and examine the html code's title element before it gets displayed like some sort of function call from the UIWebView? I'm using this to send the initial request and to print the view with the code after I see it, but I don't really ever want to see it, I just want to examine the html and pull out the code in the title element.
let url2 = NSURL(string: "myURLString") //real string is hidden
let task = NSURLSession.sharedSession().dataTaskWithURL(url2!) {(data, response, error) in
print(NSString(data: data!, encoding: NSUTF8StringEncoding))
}
task.resume()
// later I push a button and print the current page when I see my code
// on the web view with this
webView.reloadInputViews()
let html = webView.stringByEvaluatingJavaScriptFromString("document.all[0].outerHTML")
// print(html)
if let page = html{
print(html)
}
So is there a way to know that my webview has loaded a new page, or do i just have to continuously examine it and see if it has changed?
In my app I have a UICollectionView that get data from a server and shows cells with an image and user name and comment.
Every time a user posts a new image and comment a new cell is created. Right now, the UICollectionView shows the new feed just if I reload the view 2 times.
I was wondering if there is a way to update the data in the user’s interface as it changes. Without refreshing the app actually like Facebook app does?
i have been updating like this
override func viewDidLoad() {
super.viewDidLoad()
var timer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: "callbackFunction", userInfo: nil, repeats: true)
}
internal func callbackFunction() {
// do your busines logic
}
i want to load the Kepler reference Page with HttpClient like this:
string resourceAddress = _url;
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, resourceAddress);
HttpClient httpClient = new HttpClient();
// Do not buffer the response:
HttpResponseMessage response = new HttpResponseMessage();
response = await httpClient.SendAsync(request,
HttpCompletionOption.ResponseContentRead);
using (Stream responseStream = await response.Content.ReadAsStreamAsync())
{
int read = 0;
byte[] responseBytes = new byte[(Int32)responseStream.Length];
do
{
read = await responseStream.ReadAsync(responseBytes, 0, responseBytes.Length);
} while (read != 0);
}
But i think, the Page won´t be loaded complete, like without all images and iframes etc...
Downloading just the first piece of html is rarely going to be enough to give you all the elements of the page, even if you parse it and include all the linked images etc. There is also css and javascript that will bring new content into view when you open a page in a browser and getting all this yourself is going to be an effort similar to implementing your own browser. Your best bet would be to either just load the page once in a WebView control and let it cache its content or use a WebView and scan the DOM to try to get all the elements. You could also write a web service that would download the page for you and just deliver you the whole package... assuming that the page doesn't require authentication.