I am developing Android web application by using PhoneGap, it works well at most part, but sometime when I want to download or upload files, the application hang up and does not respond to any touch event till the task is finished. I am going to describe more about code I have written;
HTML code:
<a id="download">Download/a>
JavaScript code:
$("#download").click(function() {
/*Here I used a plugin which is a Java class, and call this plugin and pass the required parameters*/
var data = [id, fileName];
window.download(callServiceSuccessCallBack,
callServiceFailCallBack, "download", data);
});
The XML config file which register the plugin here:
<plugins>
<plugin name="DowloadFilePlugin" value="com.example.plugin.DowloadFilePlugin" />
</plugins>
Java code:
#Override
public boolean execute(String action, JSONArray args,
CallbackContext callbackContext) throws JSONException {
if ("download".equals(action)) {
// do something
}
return true;
}
When I press the button then the application hanged till the file downloaded.
If anyone knows about this problem please let me know how to solve, in addition i also tried window.setTimeout(code, 0); did not solve the problem.
Thanks in advance!
Try to use a setTimeout with a delay of 0 or 100ms to start your action :
$("#download").click(function() {
/*Here I used a plugin which is a Java class, and call this plugin and pass the required parameters*/
var data = [id, fileName];
setTimeout(function(){
window.download(callServiceSuccessCallBack,
callServiceFailCallBack, "download", data);
},0);
});
I solve the problem by adding thread in JAVA code as below:
#Override
public boolean execute(String action, JSONArray args, final CallbackContext callbackContext) throws JSONException {
if ("beep".equals(action)) {
final long duration = args.getLong(0);
cordova.getThreadPool().execute(new Runnable() {
public void run() {
// do something....
}
});
return true;
}
return false;
}
Related
Recently I've had the assignment to create a bi-directional interop bridge between a shell app and a webpage in .NET MAUI. Not finding any way to solve this I had the idea of creating it in Xamarin.Forms first seeing as MAUI is a continuation on it.
After having created this app, I've tried to convert it over to MAUI using Microsoft's instructions on the dotnet/maui github wiki.
The main problem i'm encountering right now is that I've been using extensions on Android's WebViewRenderer, WebViewClient and Java.Lang.Object to be able to send and receive javascript to and from the WebView.
public class ExtendedWebViewRenderer : WebViewRenderer
{
private const String JavascriptFunction = "function invokeCSharpAction(data){jsBridge.invokeAction(data);}";
public ExtendedWebViewRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<WebView> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
Control.RemoveJavascriptInterface("jsBridge");
((ExtendedWebView)Element).Cleanup();
}
if (e.NewElement != null)
{
Control.SetWebViewClient(new JavascriptWebViewClient($"javascript: {JavascriptFunction}"));
Control.AddJavascriptInterface(new JsBridge(this), "jsBridge");
}
}
}
public class JavascriptWebViewClient : WebViewClient
{
private readonly String _javascript;
public JavascriptWebViewClient(String javascript)
{
_javascript = javascript;
}
public override void OnPageFinished(WebView view, String url)
{
base.OnPageFinished(view, url);
view.EvaluateJavascript(_javascript, null);
}
}
public class JsBridge : Java.Lang.Object
{
private readonly WeakReference<ExtendedWebViewRenderer> _extendedWebViewMainRenderer;
public JsBridge(ExtendedWebViewRenderer extendedRenderer)
{
_extendedWebViewMainRenderer = new WeakReference<ExtendedWebViewRenderer>(extendedRenderer);
}
[JavascriptInterface]
[Export("invokeAction")]
public void InvokeAction(String data)
{
if (_extendedWebViewMainRenderer != null && _extendedWebViewMainRenderer.TryGetTarget(out var extendedRenderer))
{
((ExtendedWebView)extendedRenderer.Element).InvokeAction(data);
}
}
}
All three of these are either not available right now, or will not be implemented in MAUI, since a lot of platform dependent code has been automated now. Which leaves me with the problem that I can't seem to figure out how to change my current code to accomplish the same thing in MAUI.
Seeing as MAUI is currently not even fully released, I was wondering if this is currently just not possible or if there is some workaround to make it possible.
Any help would be greatly appreciated.
Calling C# from a webview is actually extremely simple. Just navigate and then intercept that in c#.
the xaml:
<WebView WidthRequest="400" HeightRequest="400" Navigating="WebView1_Navigating">
<WebView.Source>`enter code here`
<HtmlWebViewSource>
<HtmlWebViewSource.Html>
<![CDATA[
<HTML>
<script>
function callCsharp(){
window.location.href = 'http://poc.MyFunction?name=john&country=DK';
}
</script>
<BODY
A link that triggers C#
<br>
<button onclick="callCsharp()" type="button">A button calling javascript</button>
</BODY>
</HTML>
]]>
</HtmlWebViewSource.Html>
</HtmlWebViewSource>
</WebView.Source>
The C#:
private async void WebView1_Navigating(object sender, WebNavigatingEventArgs e)
{
var urlParts = e.Url.Split(".");
if (urlParts[0].ToLower().Equals("http://poc"))
{
var funcToCall = urlParts[1].Split("?");
var methodName = funcToCall[0];
var funcParams = funcToCall[1];
Debug.WriteLine("Calling " + methodName);
// prevent the navigation to complete
e.Cancel = true;
// TODO smart parsing and type casting of parameters and then some reflection magic
}
}
MAUI's default WebView has the Eval and EvaluateJavaScriptAsync functions to call JavaScript code from C#:
Eval just executes the script string you pass in a fire-and-forget way.
EvaluateJavaScriptAsync needs to be awaited but also returns a string with a stringified result of the data that the script returned.
If you want to use callback/bridge methods to automatically receive data from the JavaScript side without any input from the C# side of the app, you will have to extend the default per-platform renderers to add that functionality. The good news is that there is an official tutorial on how to do it for Xamarin Forms at Customizing a WebView which is almost straightforward to port to .NET MAUI - you only have to change how renderers are registered.
I built an android app with HTML5 and Javascript. I want to enable users to dial numbers but it is not working:
a href="tel:+201224001111">+201224001111/a>
I also added this line to android manifest xml:
uses-permission android:name="android.permission.CALL_PHONE" /
Daina, as I understand you're loading html5 into webview, right? In this case you need to set WebViewClient and override shouldOverrideUrlLoading method like:
public static final String TEL_TYPE = "tel:";
webView.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (url.contains(AppConstants.TEL_TYPE)) {
try {
activity.startActivity(new Intent(Intent.ACTION_DIAL, Uri.parse(url)));
return true;
} catch (ActivityNotFoundException e) {
//you can show toast here
return true;
}
}
return super.shouldOverrideUrlLoading(view, url);
}
});
Compare yours with
Call me at +1 (555) 555-5555
See https://mobiforge.com/design-development/mobile-friendliness-101-adding-click-to-call-links-to-a-website
This should work as click-to-call.
a better approach for HTML is:
call test
and also notice that there is no need for permissions in this method.
if you like to use internal function for call in android , you can run intents for call via :
String phnumber = "+155555555";
Intent callIntent = new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse("tel:" + phnumber));
startActivity(callIntent);
which needs call permission.
also this method below do not need permissions:
String phnumber = "+155555555";
Intent callIntent = new Intent(Intent.ACTION_DIAL);
callIntent.setData(Uri.parse("tel:" + phnumber));
startActivity(callIntent);
this will show the user dial pad and call button.
hope this will help!
I want to load contents of below web page in console application using c#.
http://justicecourts.maricopa.gov/findacase/casehistory.aspx
Using below code I am getting empty on the screen but it works perfectly if I load google.com web page.
By using WebClient and WebRequest I was getting error "Please enable javascript" and content was not loading so I used below code and javascipt error is not displaying now but web page content is not loading. I am struggling with this issue quite from long time, have seen lot of post regarding this and couldn't get this work.
Could anyone please help?
Thanks in Advance..
class Program
{
private static bool completed = false;
private static WebBrowser wb;
[STAThread]
static void Main(string[] args)
{
wb = new WebBrowser();
wb.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(wb_DocumentCompleted);
wb.Navigate("http://justicecourts.maricopa.gov/findacase/casehistory.aspx");
while (!completed)
{
Application.DoEvents();
Thread.Sleep(100);
}
Console.Write("\n\nDone with it!\n\n");
Console.ReadLine();
}
static void wb_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
Console.WriteLine(wb.Document.Body.InnerHtml);
completed = true;
}
}
If you literally just want to dump the contents of that URL out to the console, try this:
using(WebClient client = new WebClient()) {
Console.WriteLine(client.DownloadString(url));
}
try adding more wait.
static void Main(string[] args)
{
wb = new WebBrowser();
wb.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(wb_DocumentCompleted);
wb.Navigate("http://justicecourts.maricopa.gov/findacase/casehistory.aspx");
while (!completed)
{
Application.DoEvents();
Thread.Sleep(100);
}
//wait even more
for (int i = 0; i < 6; i++)
{
Application.DoEvents();
Thread.Sleep(1000);
}
Console.Write("\n\nDone with it!\n\n");
Console.ReadLine();
}
otherwise you can use EO Browser it is paid. but in your case trail will work cause it is not GUI application.as it shows trail message in GUI.
in EO you can say..
EOContorol.WebView.LoadUrlAndWait(URL);
Try using PhantomJs
basicaly like running a webbrowser without a window. (headless)
while using webbrowser control, I need to programmatically auto close a javascript confirm box.
I used below user32.dll approach and it is working fine on OS which are based english language.
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);
But if the computer running non-english OS, it is not working fine as I am using "OK" as text in above method call.
One approach which I suppose can work is I should detect OS language and then use translated "OK" text to use above method.
Here my question is can I change language of the current thread and so webbrowser control so that it show confirm box in English language? This way it would be easy and fast solution in my opinion.
Please suggest your solutions. Thanks in advance.
I am using similar approach in my code however these solutions are working for English language software only. I am actually looking for some generic solution that can run on non-english OS as well.
A possible solution consists in injecting and immediately calling a Javascript function that hijacks the original confirm function:
function hijackConfirm(){
alert('yep!');
window.oldConfirm = window.confirm;
window.confirm = function(){ return true };
}
This is an example in WPF application with the standard WPF WebBrowser control, I'm quite confident that everything I do here can be adjusted to fit the WinForm control (since the underlying ActiveX is the same).
I have a UserControl that acts as an adapter of the WebBrowser, here is the XAML:
<UserControl x:Class="WebBrowserExample.WebBrowserAdapter"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<WebBrowser x:Name="WebBrowserControl"></WebBrowser>
</Grid>
</UserControl>
First, in the WebBrowserAdapter class, you need a method to inject a javascript function in the current HTML document:
public void InjectScript(String scriptText)
{
HTMLDocument htmlDocument = (HTMLDocument)WebBrowserControl.Document;
var headElements = htmlDocument.getElementsByTagName("head");
if (headElements.length == 0)
{
throw new IndexOutOfRangeException("No element with tag 'head' has been found in the document");
}
var headElement = headElements.item(0);
IHTMLScriptElement script = (IHTMLScriptElement)htmlDocument.createElement("script");
script.text = scriptText;
headElement.AppendChild(script);
}
then you call InjectScript, when needed, whenever a document completes to load:
void WebBrowserAdapter_Loaded(object sender, RoutedEventArgs e)
{
WebBrowserControl.LoadCompleted += WebBrowserControl_LoadCompleted;
WebBrowserControl.Navigate("http://localhost:9080/console/page.html");
}
void WebBrowserControl_LoadCompleted(object sender, NavigationEventArgs e)
{
//HookHTMLElements();
String script =
#" function hijackConfirm(){
alert('yep!');
window.oldConfirm = window.confirm;
window.confirm = function(){ return true };
}";
InjectScript(script);
WebBrowserControl.InvokeScript("hijackConfirm");
}
Here I navigate to http://localhost:9080/console/page.html, which is a test page hosted on my system. This works well in this simple scenario. If you find this could apply to you, you may need to tweak a little bit the code. In order to compile the code, you have to add Microsoft.mshtml in the project references
EDIT: WinForm version
To make it work, you have to use the IE 11 engine in your application. Follow the instructions found here to set it
I just tried a WinForm version of this and it works with some minor changes. Here is the code of a form that has a WebBrowser control as one of its children:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.Load += Form1_Load;
}
void Form1_Load(object sender, EventArgs e)
{
webBrowserControl.Navigate("file:///C:/Temp/page.html");
webBrowserControl.Navigated += webBrowserControl_Navigated;
}
void webBrowserControl_Navigated(object sender, WebBrowserNavigatedEventArgs e)
{
InjectConfirmHijack();
}
private void InjectConfirmHijack()
{
String script =
#" function hijackConfirm(){
alert('yep!');
window.oldConfirm = window.confirm;
window.confirm = function(){ return true };
}";
InjectScript(script);
webBrowserControl.Document.InvokeScript("hijackConfirm");
}
public void InjectScript(String scriptText)
{
//mshtml.HTMLDocument htmlDocument = (mshtml.IHTMLDocument) webBrowserControl.Document.get;
var headElements = webBrowserControl.Document.GetElementsByTagName("head");
if (headElements.Count == 0)
{
throw new IndexOutOfRangeException("No element with tag 'head' has been found in the document");
}
var headElement = headElements[0];
var script = webBrowserControl.Document.CreateElement("script");
script.InnerHtml = scriptText;
headElement.AppendChild(script);
}
}
I have a webservice that I am trying to authenticate with in the background using a webview. When I initially send the request it will work appropriately (failure/success based on credentials), but after it seems like I am getting a cached response.
Here is my webview setup code:
WebView browser = new WebView(this);
WebSettings settings = browser.getSettings();
settings.setJavaScriptEnabled(true);
settings.setSavePassword(false);
settings.setCacheMode(WebSettings.LOAD_NO_CACHE);
settings.setAppCacheEnabled(false);
browser.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
Log.d("BROWSERPROGRESS", Integer.toString(progress));
}
});
jsInterface = new AddAccountJSInterface();
browser.addJavascriptInterface(jsInterface, "ADDACCOUNTJSINTERFACE");
browser.setWebViewClient(new AddAccountClient(this));
So as you may see I have two additional classes controlling my webView:
An object that provides an interface for javascript (AddAccountJSInterface)
A WebViewClient
Additionally I do have a WebChromeClient, but it's only there for debugging and I'm pretty sure that it won't interfere with anything.
The JS interface simply provides an easy way of getting the body HTML for performing analysis, so I'm confident that isn't the issue either.
The WebViewClient has the following code in it which does most of the "custom" work for routing based on various responses from the webservice.
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if(url.contains(INSTALL_PREFIX)) {
HashMap<String, String> params = extractParameters(url);
verificationComplete(params);
return true;
}
return false;
}
#Override
public void onPageFinished(WebView view, String url){
if(invalidShop(view)) {
Toast.makeText(context, context.getString(R.string.no_find_shop), Toast.LENGTH_SHORT).show();
shopAddressField.requestFocus();
replaceUiElements(loadingBar, addAccountButton);
} else if(url.contains(ADMIN_AUTH_LOGIN)) {
if(invalidLogin(view)) {
Toast.makeText(context, context.getString(R.string.invalid_login),Toast.LENGTH_SHORT).show();
emailField.requestFocus();
replaceUiElements(loadingBar, addAccountButton);
} else {
String email = emailField.getText().toString();
String password = passwordField.getText().toString();
String submitJS = String.format(FORM_SUBMISSION_JS, email, password);
jsInterface.setInnerHTML("");
browser.loadUrl(submitJS);
}
}
}
In my activity I have 3 text fields that I need to fill followed by clicking a button to submit it. The activity then takes in the data from 3 text fields (shopAddressField, usernameField, passwordField) and then executes some javascript that populates some form data (which was loaded in the invisible webView) then clicks the submit button.
It is the last part that is messing up, which appears to be caching the response from the server (perhaps using cookies?) and return that instead of asking the server if the data is correct or not.
A bit of clarification:
JSInterface is simply a Java object that allows me to execute javascript on my webview which is tied to a function within that object. In my case my JSInterface has one function which is setInnerHtml(String html).
This is the javascript that is executed on the webview:
javascript:window.ADDACOUNTJSINTERFACE.setInnerHTML(document.body.innerHTML)
And this is the setInnerHtml function:
public void setInnerHtml(String innerHtml) {
this.innerHtml = innerHtml;
}
So when I actually execute jsInterface.setInnerHtml("") I'm just over-writing the HTML that was pulled in (to be sure I'm not getting my old data from there for some reason).
As for my submitJS it is once again some Javascript that is executed on my webView as follows:
// submitJS will be something like this once all the credentials have been set
// Note: I know that the server will make jQuery available
// Note: Much of the Java string formatting has been removed to help clarify
// the code.
String submitJS =
"javascript:(function() {
$('login-input').value='username';
$('password').value='password';
$('sign-in-form').up().submit();
})()"
// I then simply get the webview to execute the javascript above
webView.loadData(submitJS);
So it turns out the problem wasn't based around the Caching, and possibly not cookies.
When executing javascript on your webView it does this in a separate thread and can be quite slow. This lead to a race condition which caused code to be executed in the wrong order.
I've solved this problem by using a Semaphore as a Mutex. This allows me to prevent my getter from returning before the Javascript on the webView is able to execute.
The interface I created now looks like this:
private class AddAccountJSInterface {
private final String TAG = getClass().getName().toUpperCase();
private Semaphore mutex = new Semaphore(1, false);
private String innerHTML;
public void aquireSemaphore() {
Log.d(TAG, "Attempting to lock semaphore");
try {
mutex.acquire();
} catch(InterruptedException e) {
Log.d(TAG, "Oh snap, we got interrupted. Just going to abort.");
return;
}
Log.d(TAG, "Semaphore has been aquired");
}
#SuppressWarnings("unused")
public void setInnerHTML(String html) {
this.innerHTML = html;
Log.d(TAG, "setInnerHTML is now releasing semaphore.");
mutex.release();
Log.d(TAG, "setInnerHTML has successfully released the semaphore.");
}
public synchronized String getInnerHTML() {
Log.d(TAG, "getInnerHTML attempting to aquire semaphore, may block...");
String innerHTML = "";
try {
mutex.acquire();
Log.d(TAG, "getInnerHTML has aquired the semaphore, grabbing data.");
innerHTML = this.innerHTML;
Log.d(TAG, "getInnerHTML no longer needs semaphore, releasing");
mutex.release();
} catch (InterruptedException e) {
Log.d(TAG, "Something has gone wrong while attempting to aquire semaphore, aborting");
}
return innerHTML;
}
}
Now the way I use this in my code is as follows:
// I have access to the jsInterface object which is an instance of the class above as well as a webView which I will be executing the javascript on.
String getInnerHtmlJS = "javascript:window.MYJSINTERFACE.setInnerHTML(document.body.innerHTML);"
jsInterface.aquireSemaphore()
// Execute my JS on the webview
jsInterface.loadUrl(getInnerHtmlJS)
// Now we get our inner HTML
// Note: getInnerHTML will block since it must wait for the setInnerHTML (executed via the JS) function to release the semaphore
String theInnerHTML = jsInterface.getInnerHTML();