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Webview activity not showing anything on second load

I have this weird problem when showing an activity which consists (only) out of a webview.
The first time I start this Activity B by clicking on something in activity A, B is properly loaded and functional. I press the return button, go back to A, then click on the same button to go to B and my webview doesn't show anything. Debugged it tons of times and nothing seems out of the ordinary. There are also no crashes in the stack trace log... This problem by the wway occurs always in debug mode and only sometimes in run mode.
Here is the code for the activity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_spin);
myItem = (Item) getIntent().getSerializableExtra("Item");
initView();
initHandlers();
}
private void initView()
{
webView = findViewById(R.id.webview_spin);
//TODO : webViewClient vs webChromeClient ?
webView.setWebViewClient(new WebViewClient());
webView.setWebChromeClient(new WebChromeClient());
webView.getSettings().setJavaScriptEnabled(true);
String json = new Gson().toJson(myItem);
webView.loadUrl("file:///android_asset/item.html?item="+json);
}
private void initHandlers()
{
OrientationEventListener orientationEventListener = new OrientationEventListener(this) {
#Override
public void onOrientationChanged(int orientation) {
webView.reload();
}
};
orientationEventListener.enable();
}
FYI this problem occured before setting the orientationlistener.

That looks like somehow the render process of the WebView is failing. You could store the WebViewClient you created on a variable and check the result of its method onRenderProcessGone() to check if it is rendering the second time you load the activity. Here you have all the WebViewClient methods: https://developer.android.com/reference/android/webkit/WebViewClient

How to create a wrapper object for a webview

so I have a working webview that is simple, but most of the work is done in the main activity. I am trying to break it out to its own little class so I can load other classes into the main activity on the fly. I am stuck on how to do this. I have tried this a few times and been debugging it but I just dont know if I am using the right findByValue(R.id.webView); thing here. it keeps giving me a
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.webkit.WebView.findViewById(int)' on a null object reference
issue. I have tried passing the reference in as a parameter and also hard coded it. I am missing something but dont know what. There is a WebView in my activity_main that is called wevView that is what I am trying to find out where i'm did mistake.
Thanks for any help with this.
So this is my webview class:
public class NewWebView {
//variables need for webview
private final String myPage = "http://www.google.com";
WebView myWebView = null;
//consturctor
public NewWebView(){}
//This method creates the WebView
public void createWebView(WebView webView)
{
//WebView code
//Find the Webview in the Activity.xml file
//myWebView = webView;
myWebView = (WebView)myWebView.findViewById(R.id.webview);
// myWebView = (android.webkit.WebView)findViewById(R.id.webview);
//Use the custom WebViewClient for internal app browsing
myWebView.setWebViewClient(new MyWebViewClient());
//now for enabling the settings
WebSettings webSettings = myWebView.getSettings();
//Enable JavaScript
webSettings.setJavaScriptEnabled(true);
//Enable andriod zoom features
webSettings.setBuiltInZoomControls(true);
//Loading the Url
myWebView.loadUrl(myPage);
}
//Methods Used for WebViewer
//custom WebViewClent needed for internal app navigatiion
private class MyWebViewClient extends WebViewClient
{
public boolean shouldOverRideUrlLoading(android.webkit.WebView view, String url)
{
if(Uri.parse(url).getHost().equals(myPage))
{
//this is Apivita remain in the APP
return false;
}
/*
//if it is not in my site redirect it to mobile browers
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(intent);
return true;
*/
return true;
}
}
//Enable the use of the system back button for navigation
public boolean onKeyDown(int keyCode, KeyEvent event)
{
//if the back button was pushed
if((keyCode == KeyEvent.KEYCODE_BACK) && myWebView.canGoBack())
{
myWebView.goBack();
return true;
}
//if not
return false;
}
}
and here is the main activity
public class MainActivity extends AppCompatActivity {
WebView myWebView = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//create the webview
myWebView = (android.webkit.WebView)findViewById(R.id.webview);
NewWebView apWebView = new NewWebView();
apWebView.createWebView(myWebView);
}
}

It looks like you are finding your webview in the main activity and then passing it into your class. In your custom class, you're then trying to find another view, which you technically already have. So its trying to find a webview, inside of the webview. It obviously can't find this, so it's null.
In theory, you should be able to just use myWebView = webView;, however, you need to make sure that it is finding it in the first place.

Trouble with inserting JavaScript statement

I am currently creating an android application.
The aim of the application is to fire off some injected JavaScript code into the WebView that I have created within my android application. The problem that I am having is that the action that has been injected doesn't work.
You should also be aware that the html page that I am loading has been created locally. aim of the application is to have a toast message display.The code listing is below:
//uses javascript that is in the local HTML file
public class MainActivity extends Activity {
final String URL = "file:///android_asset/index.html";
private WebView myWebView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView myWebView = (WebView) findViewById(R.id.webview);
WebSettings webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
myWebView.addJavascriptInterface(new WebAppInterface(this), "Android");
String test= "test";
String javascript ="javascript:document.addEventListener('click', function(){Android.showToast(toast)})";
myWebView.loadUrl(javascript);
myWebView.loadUrl(URL);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public class WebAppInterface {
Context mContext;
/** Instantiate the interface and set the context */
WebAppInterface(Context c) {
mContext = c;
}
/** Show a toast from the web page */
#JavascriptInterface
public void showToast(String toast) {
Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
}
}
}

There are several issues with your implementation.
The toast variable might not be defined in the scope of your callback. Also, you are missing two semicolons, one right after calling the showToast method, and the other one at the end of the addEventListener method which results in a syntax error.
Finally, you are loading the Javascript code before loading the page, which gets it invalidated. You should be injecting your javascript code after the webpage has finished loading such as in the below example.
I've taken your example and rewrote it in a custom app to make sure it was working. Here's what I've written :
Android :
// Registering the JS interface
mWebView.addJavascriptInterface(new JSInterface(), "JSInterface");
// Waiting for the page to be fully loaded, and injecting the JS code
mWebView.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
return false;
}
#Override
public void onPageFinished(WebView view, String url) {
view.loadUrl(INJECTED_CODE);
}
});
// Load your custom url
mWebView.loadUrl(YOUR_ACTUAL_URL);
/**
* Interface between Java and Javascript.
*/
public class JSInterface {
#JavascriptInterface
public void showToast(String toast) {
Log.d("debug", "I got : " + toast);
}
}
Injected javascript :
public static final String INJECTED_CODE = "javascript:"
+ "(function() { "
+ "document.addEventListener('click', function(){JSInterface.showToast('Hello Android !');});"
+ "})()";

You are attempting to call that JS code before loading your html page.
I would guess that the document object is not ready.
Change your event listener and bind to the window
From:
String javascript ="javascript:document.addEventListener('click', function(){Android.showToast(toast)})";
To:
String javascript ="javascript:window.addEventListener('click', function(){Android.showToast(toast)})";
And you should get a result. If not what is logcat spitting out when you click?
EDIT: Just saw Halim Qarroums onPageFinished solution, that is probably a better one in your case.

How to setup Android WebView to make it work identically Android browser?

What are the settings to enable or disable in WebView to do this?

If you want to use a webview with exactly the same features as the native android browser, you have to check MANY options and settings. A WebView is made to NOT use all of the browsers options and settings for better performance and for having more controll on what the users can and can not do while browsing. to figure out all the opportunities you should read through the api documentation here:
http://developer.android.com/reference/android/webkit/WebView.html
For some further dealing and handling with the WebView class also here are some usefull sample codelines:
http://pankajchunchun.wordpress.com/2013/01/09/example-of-webview-with-result-handler-and-connection-timeout-handler/
I hope this will help you.

this is the webview example source..
what kind of setting do you wanna know??
public class MainActivity extends Activity {
WebView webview;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
webview = (WebView)findViewById(R.id.webview);
webview.setWebViewClient(new WebClient());
WebSettings set = webview.getSettings();
set.setJavaScriptEnabled(true);
set.setBuiltInZoomControls(true);
webview.loadUrl("http://www.google.com");
findViewById(R.id.btnStart).setOnClickListener(onclick);
}
OnClickListener onclick =new OnClickListener() {
#Override
public void onClick(View v) {
String url= null;
EditText add = (EditText)findViewById(R.id.add);
url = add.getText().toString();
webview.loadUrl(url);
}
};
class WebClient extends WebViewClient {
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}

In addition to #Ssam's answer, you might want to manage the back button press so your app/Activity doesn't get closed on back press.
#Override
public void onBackPressed() {
if (webview.canGoBack()) {
webview.goBack();
}else
super.onBackPressed();
}
where webview is your webview

android application is opening a browser application instead of a webView, how do I stop that?

Right now when I push a specific button it starts an intent to open a web page into a webView, but instead it opens a Browser Application, revealing the address bar which is not what I want.
After doing some research I found out I can use the shouldOverrideUrlLoading() method to stop this from happening and just open the page in a webView, but I don't know how to implement this method in my code, help would be greatly appreciated!
This is what I have in the class where I'm opening the web page:
public class Codes extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.codes);
View titleView = getWindow().findViewById(android.R.id.title);
if (titleView != null) {
ViewParent parent = titleView.getParent();
if (parent != null && (parent instanceof View)) {
View parentView = (View)parent;
parentView.setBackgroundColor(Color.rgb(228, 108, 10));
}
}
WebView codes = (WebView)findViewById(R.id.codesWebView);
codes.getSettings().setJavaScriptEnabled(true);
codes.loadUrl("http://dev10.affirmaconsulting.com:24009/keyentry");
shouldOverrideUrlLoading(codes, "http://dev10.affirmaconsulting.com:24009/keyentry");
}
}

I had this same problem, that pages were not loading in my webview but instead via the browser application. I resolved the issue by implementing a WebViewClient class and overriding the shouldOverrideUrlLoading method.
WebViewClient webClient = new WebViewClient()
{
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
return false;
}
};
webView.setWebViewClient(webClient);
The following link proved to be helpful:
http://www.firstdroid.com/2010/08/05/override-url-loading-in-webview-android-tutorial/

We do this exact task in one of our activities and haven't ran into this issue. Here is what ours looks like:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.document_viewer_activity);
WebView wv = (WebView) findViewById(R.id.documentViewerWebview);
wv.getSettings().setJavaScriptEnabled(true);
String url = getString(R.string.document_viewer_url) +
getIntent().getExtras().getString("media");
wv.loadUrl(url);
}
With the webview defined in the layout file looking like this:
<WebView
android:id="#+id/documentViewerWebview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
Hope this helps.