Develop Reference

Xamarin Android WebView don't fire navigating if "target=_blank"

I'm using a webview in xamarin, i followed many tutorials to handle navigation, and all works fine.
My issue is : when an anchor tag has a target="_blank" the event Navigating is never fired.
I see arround someone give a javascript solution which remove target=_blank and attach it at the end of href link.
Is really that the right way to do that? Look wired..
Thank you
This is initialization in xamarin.android renderer
protected override void OnElementChanged(ElementChangedEventArgs<WebView> e)
{
base.OnElementChanged(e);
global::Android.Webkit.WebView.SetWebContentsDebuggingEnabled(true);
if (e.OldElement != null)
{
Control.RemoveJavascriptInterface("jsBridge");
((HybridWebView)Element).Cleanup();
}
if (e.NewElement != null)
{
Control.Settings.JavaScriptEnabled = true;
Control.Settings.DomStorageEnabled = true;
Control.Settings.JavaScriptCanOpenWindowsAutomatically = true;
Control.Settings.SetSupportMultipleWindows(true);
Control.Settings.AllowFileAccessFromFileURLs = true;
Control.Settings.AllowUniversalAccessFromFileURLs = true;
Control.Settings.UserAgentString = Control.Settings.UserAgentString + " crmvw";
Android.Webkit.WebChromeClient xCC = new CustChromeWebViewClient(_context);
Control.SetWebChromeClient(xCC);
Control.SetWebViewClient(new CrmWebViewClient(this, $"javascript: {JavascriptFunction}"));
Control.AddJavascriptInterface(new JSBridge(this), "jsBridge");
Control.LoadUrl(((HybridWebView)Element).Uri);
}
}
And this is my navigating event, never fired when anchor has target=_blank
private void webv_Navigating(object sender, WebNavigatingEventArgs e)
{
if (IsFirstLoad) {
IsBusy = true;
IsFirstLoad = false;
}
if (e.Url.ToLower().StartsWith("tel:") || e.Url.ToString().StartsWith("wtai:") || e.Url.ToLower().StartsWith("sms:") || e.Url.ToLower().StartsWith("mailto:"))
{
e.Cancel = true;
}
}
here my override function for URL in my custom WEBView
public override bool ShouldOverrideUrlLoading(Android.Webkit.WebView view, Android.Webkit.IWebResourceRequest request)
{
Android.Net.Uri url = request.Url;
if (url.ToString().StartsWith("tel:") || url.ToString().StartsWith("wtai:"))
{
Xamarin.Essentials.PhoneDialer.Open(UtilityXam.Contact.GetPhoneFromHTML(url.ToString()));
return true;
}else if (url.ToString().StartsWith("mailto:"))
{
UtilityXam.Contact xE = new UtilityXam.Contact();
string xEmail = UtilityXam.Contact.GetEmailFromHTML( url.ToString());
var xTask = xE.SendEmail("","",new System.Collections.Generic.List<string>(){ xEmail });
return true;
}
else if (url.ToString().StartsWith("sms:"))
{
UtilityXam.Contact xE = new UtilityXam.Contact();
string xPh = UtilityXam.Contact.GetPhoneFromHTML(url.ToString());
var xTask = xE.SendSMS("", "", new System.Collections.Generic.List<string>() { xPh });
}
else
{
view.LoadUrl(url.ToString());
}
view.SetDownloadListener(new CrmDownloadListener(_context));
return true;
}

After the great help of Jack Hua i'm able to solve the problem.
In OnElementChanged of Hybrid renderer i set support for multiple windows.
Control.Settings.SetSupportMultipleWindows(true);
and next i had to menage onCreateWindow event in the custom chrome webview.
Here the code converted in c# from the link suggested by Jack.
public override bool OnCreateWindow(Android.Webkit.WebView view, bool isDialog, bool isUserGesture, Android.OS.Message resultMsg)
{
Android.Webkit.WebView newWebView = new Android.Webkit.WebView(_context);
view.AddView(newWebView);
Android.Webkit.WebView.WebViewTransport transport = (Android.Webkit.WebView.WebViewTransport) resultMsg.Obj;
transport.WebView = newWebView;
resultMsg.SendToTarget();
return true;
}

This is an introduced bug in Xamarin Forms since v4.8.0.1364 (According to the bug report at least)
You can work around it for now by removing the target="_blank" from the url or by setting a property
webView.Settings.SetSupportMultipleWindows(true);
I have fixed it for our app by striping target="_blank" and target='_blank' in some replacement logic that already runs over the content
There are multiple open issues reporting it for Xamarin Forms github
[Bug] Cannot open URLs with WebView android when the target is _blank #12917
[Bug] Android WebView's Navigating and Navigated events not fired #12852

I tried a completely different approach, because the above answers didn't really help (my target _blank links would always open in a new chrome instance and not in the in-app browser).
First, you'll need to set SetSupportMultipleWindows to false. As soon as you do that, all the windows will open in the same webView:
Control.Settings.SetSupportMultipleWindows(false);
More information on how you set these settings: https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/custom-renderer/hybridwebview
Next, all I did was change the back-button behaviour, to make sure the back button doesn't close the app and instead navigates the webview pages (HybridWebView is my custom webview that I created in the first step).
HybridWebView _browser;
public MainPage()
{
_browser = new HybridWebView
{
Source = "https://brandschutzplaner-stahltragwerke.promat.ch"
};
Content = _browser;
}
protected override bool OnBackButtonPressed()
{
base.OnBackButtonPressed();
if (_browser.CanGoBack)
{
_browser.GoBack();
return true;
}
else
{
base.OnBackButtonPressed();
return true;
}
}

How to disable copy paste buttons in Edittext

I am developing an App in android, i want to disable copy paste buttons onLongClick,
I am using the following code:
edittext.setCustomSelectionActionModeCallback(new Callback() {
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
return false;
}
public void onDestroyActionMode(ActionMode mode) {
}
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
return false;
}
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
return false;
}
});
But it is showing error as
"The method setCustomSelectionActionModeCallback(ActionMode.Callback) in the type TextView is not applicable for the arguments (new ActionMode.Callback(){})".
I am searching for hours to get the solution. Please provide me solution.

Add
import android.view.ActionMode.Callback;
to your imports
OR
if you have another Callback class already imported change
edittext.setCustomSelectionActionModeCallback(new Callback() {
to
edittext.setCustomSelectionActionModeCallback(new android.view.ActionMode.Callback() {

You are getting error in above method because the method is included in API Level 13+ and your current compilation version may be set to lower.
Right Click on project -> properties -> "Android Tab" -> select api level 13 or greater.
If you wants backward support, you can try these tricks.
1)
OnLongClickListener mOnLongClickListener = new OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
//since nothing is in here, nothing will happen.
return true;
}
};
2)
edtPassword.setLongClickable(false);
3) IN XML
android:longClickable="false"
NOTE :
The method you are trying will only works with API level 13+. But these tricks will work with lower aloso

I found one hack. It's working charm:
OnLongClickListener mOnLongClickListener = new OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
//since nothing is in here, nothing will happen.
setEnabled(false);
setEnabled(true);
return false;
}
};
Do same for onClick event of OnClickListener.

Getting "Link text" of the link displayed in WebView

I have Android WebView which displays some links as: Link1TextLink2Text Now I would like to retrieve Link1Text and Link2Text when I long press these links. I have contextMenu implemented in the code and I could successfully get the link urls (http://link1.html, http://link2.html) using HitTestResult getExtra() method but how ccan I get those link texts ?FYI, I require those link texts for implementing "Copy link text" option in the contextMenu.

To get the text of an achor link:
I. Hook a touchstart listener to every web pages in the onPageFinished() callback of WebViewClient via evaluateJavascript. like:
//Javascripts to evaluate in onPageFinished
const w=window;
w.addEventListener('touchstart',wrappedOnDownFunc);
function wrappedOnDownFunc(e){
if(e.touches.length==1){
w._touchtarget = e.touches[0].target;
}
console.log('hey touched something ' +w._touchtarget);
}
note we've saved the touch target.
II. Then implement OnLongClicklisenter for webview. use evaluateJavascript again when you long pressed on a link object:
#Override
public boolean onLongClick(View v) {
WebView.HitTestResult result = ((WebView)v).getHitTestResult();
if (null == result) return false;
int type = result.getType();
switch (type) {
case WebView.HitTestResult.SRC_ANCHOR_TYPE:
if(result.getExtra()!=null){
((WebView)v).evaluateJavascript("window._touchtarget?window._touchtarget.innerText:''", new ValueCallback<String>() {
#Override
public void onReceiveValue(String value) {
System.out.println("hey received link text : "+value);
}
});
}
return true;
}
return false;
}
What's more, we can even choose to select the text of the anchor element! Actually this is one of the options that samsung browser offers when you long-pressed an tag .
To achieve this, we still need that recorded touch target. Besides we need 2 new javascript methods:
function selectTouchtarget(){
var tt = w._touchtarget;
if(tt){
w._touchtarget_href = tt.getAttribute("href");
tt.removeAttribute("href");
var sel = w.getSelection();
var range = document.createRange();
range.selectNodeContents(tt);
sel.removeAllRanges();
sel.addRange(range);
}
}
function restoreTouchtarget(){
var tt = w._touchtarget;
if(tt){
tt.setAttribute("href", w._touchtarget_href);
}
}
Finnaly in the onLongClick listener, instead of just fetch the innerText, we programmatically set the selection, trigger the action menu bar, and restore the removed href attribute of our touch target.
case WebViewmy.HitTestResult.SRC_ANCHOR_TYPE:
if(result.getExtra()!=null){
WebViewmy mWebView = ((WebViewmy)v);
mWebView.evaluateJavascript("selectTouchtarget()", new ValueCallback<String>() {
#Override
public void onReceiveValue(String value) {
/* bring in action mode by a fake click on the programmatically selected text. */
MotionEvent te = MotionEvent.obtain(0,0,KeyEvent.ACTION_DOWN,mWebView.lastX,mWebView.lastY,0);
mWebView.dispatchTouchEvent(te);
te.setAction(KeyEvent.ACTION_UP);
mWebView.dispatchTouchEvent(te);
te.recycle();
//if it's not delayed for a while or the href attribute is not removed, then the above code would click into
// the anchor element instead of select it's text.
/* restore href attribute */
mWebView.postDelayed(() -> mWebView.evaluateJavascript("restoreTouchtarget()", null), 100);
}
});
}
return true;
In my case, I've extended the WebView as WebViewmy to record last touched positions, lastX and lastY, in the onTouchEvent method.

Unfortunately, a clear, official way to do this is not available. Although, there are two APIs (selectText and copySelection) which are pending API council approval, that may help to do this, but they are not available at the moment.

Accessibility function implementation problems in Android

I'm developing application that views books. There is a screen (Activity) which shows a book. It has custom view, something similar to ViewSwitcher and every page is a bitmap that is rendered by a custom View.
Now I should implement accessibility function - book should be read by the phone (audio).
I've read Accessibility section here https://developer.android.com/guide/topics/ui/accessibility/index.html but it is not clear enough.
I use SupportLibrary for accessibility management and now I have this code in ViewGroup (which manages book pages). Code 1:
private class EditionPagesViewSwitcherAccessibilityDelegate extends AccessibilityDelegateCompat {
private int mPageCount;
private double[] mPageRange;
#Override
public void onInitializeAccessibilityEvent(final View host, final AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(host, event);
event.setClassName(EditionPagesViewSwitcher.class.getName());
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
event.setScrollable(canScroll());
}
if (event.getEventType() == AccessibilityEventCompat.TYPE_VIEW_SCROLLED && updatePageValues()) {
event.setItemCount(mPageCount);
// we use +1 because of user friendly numbers (from 1 not 0)
event.setFromIndex((int) (mPageRange[0] + 1));
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
event.setToIndex((int) (mPageRange[1] + 1));
}
}
}
#Override
public void onInitializeAccessibilityNodeInfo(final View host, final AccessibilityNodeInfoCompat info) {
super.onInitializeAccessibilityNodeInfo(host, info);
info.setClassName(EditionPagesViewSwitcher.class.getName());
info.setScrollable(canScroll());
info.setLongClickable(true);
if (canScrollForward()) {
info.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD);
}
if (canScrollBackward()) {
info.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD);
}
}
#Override
public boolean performAccessibilityAction(final View host, final int action, final Bundle args) {
if (super.performAccessibilityAction(host, action, args)) {
return true;
}
switch (action) {
case AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD: {
if (canScrollForward()) {
showNext();
return true;
}
}
return false;
case AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD: {
if (canScrollBackward()) {
showPrevious();
return true;
}
}
return false;
}
return false;
}
Here is code from page view Code 2:
#Override
public void onInitializeAccessibilityEvent(final View host, final AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(host, event);
event.setClassName(EditionPageView.class.getName());
if (hasText()) {
event.getText().add(getPageRangeText());
final String trimText = mSurfaceUpdateData.getPageText().trim();
if (trimText.length() > MAX_TEXT_LENGTH) {
event.getText().add(trimText.substring(0, MAX_TEXT_LENGTH));
// event.getText().add(trimText.substring(MAX_TEXT_LENGTH, trimText.length()));
}
else {
event.getText().add(trimText);
}
}
}
#Override
public void onInitializeAccessibilityNodeInfo(final View host, final AccessibilityNodeInfoCompat info) {
super.onInitializeAccessibilityNodeInfo(host, info);
info.setClassName(EditionPageView.class.getName());
}
Because page text data loads asynchronous first time accessibility don't have any text while executes onInitializeAccessibilityEvent code. And then when data have been loaded I fire AccessibilityEvent.TYPE_VIEW_SELECTED and AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED events. Then onInitializeAccessibilityEvent executes again and phone "read" book text.
So my questions:
Is my Accessibility implementation right? May be it is design wrong? Because I didn't find any good tutorial about this feature.
Why I need to use SDK versions checks in Support implementations in Code 1? Why support implementation doesn't handle it correctly?
Is firing TYPE_VIEW_SELECTED and TYPE_VIEW_TEXT_CHANGED really needed? Or may be some other code should be implemented?
The main question. In Code 2 there is commented code line. This code statement substring text to be less then MAX_TEXT_LENGTH (it's 3800) because if text is bigger nothing is played. Nothing. Is it accessibility restriction? Any other text that is less then this value is played well.
Does anyone know where I can find any good tutorial? (yes I saw samples).
Does anyone have any custom realizations to look through?
UPDATED
Well. Here is some answers:
As I can see TYPE_VIEW_SELECTED and TYPE_VIEW_TEXT_CHANGED events are not needed if you don't want this text to be read as soon as you get it.
On Nexus 7 all large text is played well (text up to 8000 symbols), so this issue doesn't reproduce on it, but on Samsung Galaxy Tab 10.1 (Android 4.0.4) and Genymotion emulator of Tab 10.1 with Android 4.3 does. And this is strange...

4.. According to the documentation of String.substring()
The first argument you pass is the start index in the original string, the second argument is the end index in the original string.
Example:
String text = "Hello";
partOfText = text.substring(2,text.length() - 1);
partOfText equals to "llo" (the first char is index 0)
So by putting your constant MAX_TEXT_LENGTH as a first argument, it would start at index 3800 to take out the substring.
http://developer.android.com/reference/java/lang/String.html#substring(int)

You are right MAX_TEXT_LENGTH is 3800.
About your doubt,
this code:
event.getText().add(trimText.substring(MAX_TEXT_LENGTH, trimText.length()));
}
you are trying to substring "trimText" from MAX_TEXT_LENGTH to trimText.length() !
Supposing that trimText = "STACK", trimText.length() = 5, then trimText.substring(3800,5) is going to be ?
At first, this doesn't have sense, using correctly would be like this:
trimText.substring(0,2) = "ST";

Anybody know how to select text in webview in android? not use emulateShiftHeld,since the docs said " This method is deprecated"

I try to select text in webview, after I select text,I need to decide what to do next.not just copy the selected text.I have more choice for user to choose from.I mean, after user selected text in webview,could I prompt out a some button for further? I tried use emulateshiftheld to solve my problem.but google's docs said " This method is deprecated".
also,I can't prompt out some choice button.
you can clck the link to see what I mean. link: https://public.blu.livefilestore.com/y1pHhMR2iyIbQN7uJ2C-9CLLJBosWAZw2r4MvD0qyyTG-QWUM-06i6HFu4Fn4oaWnHMbDyTBOa-CPwN6PwoZNifSQ/select.jpg?download&psid=1

Pasting relevant code from WebView emulateShiftHeld() on Android Newer SDK's
/**
* Select Text in the webview and automatically sends the selected text to the clipboard
*/
public void selectAndCopyText() {
try {
KeyEvent shiftPressEvent = new KeyEvent(0,0,KeyEvent.ACTION_DOWN,KeyEvent.KEYCODE_SHIFT_LEFT,0,0);
shiftPressEvent.dispatch(mWebView);
} catch (Exception e) {
throw new AssertionError(e);
}
}

The question is very old, but for other people here is a solution with javascript for API 19+. Just add this to your WebView:
public void getSelectedText(final SelectedTextInterface selectedTextInterface) {
evaluateJavascript("(function(){return window.getSelection().toString()})()", new ValueCallback<String>() {
#Override
public void onReceiveValue(final String selectedText) {
if (selectedText != null && !selectedText.equals("")) {
//If you don't have a context, just call
//selectedTextInterface.onTextSelected(selectedText);
if (context instanceof Activity) {
((Activity) context).runOnUiThread(new Runnable() {
#Override
public void run() {
selectedTextInterface.onTextSelected(selectedText);
}
});
} else selectedTextInterface.onTextSelected(selectedText);
}
}
});
}
public interface SelectedTextInterface {
void onTextSelected(String selectedText);
}
When you are done with selecting text, just call it with:
webView.getSelectedText(new YourWebView.SelectedTextInterface() {
#Override
public void onTextSelected(String selectedText) {
//Your code here
}
});
I hope this may be useful for some people :-)