I'm running a WebView Android App that points to a WebApp. Everything ok. But now, I'm having problem to refresh the url which is already loaded when the method onNewToken from FirebaseMessagingService is called and also inject a JS into it. I have heard about Intents and also found this question but can't really understand how and where to apply the Intents.
Here is what my code currently looks like:
MyFirebaseMessagingService:
package com.example.app;
import android.util.Log;
import com.google.firebase.messaging.FirebaseMessagingService;
public class MyFirebaseMessagingService extends FirebaseMessagingService {
private static final String TAG = "MyFirebaseMessagingService";
#Override
public void onNewToken(String token) {
Log.d(TAG, "Refreshed token: " + token);
// I want to call the loadUrl here using a injected JS to send the token to the Web App
}
}
MyWebViewClient:
package com.example.app;
import android.content.Intent;
import android.net.Uri;
import android.util.Log;
import android.webkit.WebResourceRequest;
import android.webkit.WebView;
import android.webkit.WebViewClient;
class MyWebViewClient extends WebViewClient {
private static final String TAG = "MyWebViewClient";
#Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
String hostname;
// YOUR HOSTNAME
hostname = "192.168.0.11";
final Uri uri = request.getUrl();
Log.i(TAG, "Uri =" + uri);
if (uri.getHost() != null && uri.getHost().endsWith(hostname)) {
return false;
}
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
view.getContext().startActivity(intent);
return true;
}
}
MainActivity:
package com.example.app;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;
public class MainActivity extends Activity {
public WebView mWebView;
#Override
#SuppressLint("SetJavaScriptEnabled")
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mWebView = findViewById(R.id.activity_main_webview);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setDomStorageEnabled(true);
webSettings.setDatabaseEnabled(true);
mWebView.setWebViewClient(new MyWebViewClient());
// REMOTE RESOURCE
mWebView.loadUrl("http://192.168.0.11:3000/");
// LOCAL RESOURCE
// mWebView.loadUrl("file:///android_asset/index.html");
}
#Override
public void onBackPressed() {
if(mWebView.canGoBack()) {
mWebView.goBack();
} else {
super.onBackPressed();
}
}
}
Yes you have to use Intents but at first use LocalBroadcastManager in your "MyFirebaseMessagingService" :
public static String REQUEST_ACCEPT="action.my.messaging";
#Override
public void onNewToken(String token) {
Log.d(TAG, "Refreshed token: " + token);
//after any refresh you will notice it to your activity (or fragment)
Intent intent = new Intent(REQUEST_ACCEPT);
intent.putExtra("key", "Any Extra Value Here");
LocalBroadcastManager.getInstance(getBaseContext()).sendBroadcast(intent);
}
#Override
public void onMessageReceived(RemoteMessage remoteMessage) {
//Or use it here after any message received
}
Then in your activity you can receive any notices and do the refresh or any action you want:
#Override
public void onCreate(Bundle savedInstanceState) {
// registering an observer (mMessageReceiver) to receive Intents
// with actions named as the value of REQUEST_ACCEPT.
LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver,
new IntentFilter(MyFirebaseMessagingService.REQUEST_ACCEPT));
}
// Our handler for received Intents. This will be called whenever an Intent
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// Get extra data included in the Intent
String value = intent.getStringExtra("key");
Log.d(TAG, "Got noticed: " + value );
}
};
#Override
protected void onDestroy() {
// Unregister since the activity is about to be closed.
LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
super.onDestroy();
}
Related
Im not and Android or Java Developer, I fullstack web developer..but I have a template for making webviews project that works in most of the cases...but with this login doesnt work..
I have a site tha use the facebook Js SDK Version 3.2
It works perfect on: Google Chrome in my Laptop.
It works perfect on: Google Chrome in my Phone
but in APP in the webView after i Insert user and password of Facebook and press login it freezes.
I think it cant return to the previous page..
I read a lot of post here but nothing works..
this is my MainActivity:
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.net.http.SslError;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.CookieManager;
import android.webkit.SslErrorHandler;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceError;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.FrameLayout;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private static final String target_url = "https://myapp.com/gen_age/index.php";
private static final String target_url_prefix = "myapp.com/gen_age/index.php";
private WebView mWebview;
private WebView mWebviewPop;
private FrameLayout mContainer;
private SwipeRefreshLayout swipeLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CookieManager cookieManager = CookieManager.getInstance();
cookieManager.setAcceptCookie(true);
mWebview = findViewById(R.id.webView);
mContainer = findViewById(R.id.webview_frame);
swipeLayout = findViewById(R.id.swipe_container);
final WebSettings webSettings = mWebview.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setAppCacheEnabled(true);
webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
webSettings.setSupportMultipleWindows(true);
mWebview.setWebViewClient(new UriWebViewClient());
mWebview.setWebChromeClient(new UriChromeClient());
mWebview.loadUrl(target_url);
swipeLayout.setRefreshing(true);
swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
//Do your task
mWebview.reload();
}
});
}
private class UriWebViewClient extends WebViewClient {
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
swipeLayout.setRefreshing(false);
}
#Override
public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
super.onReceivedError(view, request, error);
swipeLayout.setRefreshing(false);
}
#Override
public void onReceivedHttpError(WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
super.onReceivedHttpError(view, request, errorResponse);
swipeLayout.setRefreshing(false);
}
#Override
public boolean shouldOverrideUrlLoading(final WebView view, final String url) {
try {
String host = Uri.parse(url).getHost();
//Log.d("shouldOverrideUrlLoading", url);
if (host.equals(target_url_prefix)) {
// This is my web site, so do not override; let my WebView load
// the page
if (mWebviewPop != null) {
mWebviewPop.setVisibility(View.GONE);
mContainer.removeView(mWebviewPop);
mWebviewPop = null;
}
return false;
}
if (host.equals("m.facebook.com")) {
return false;
}
} catch (Exception e) {
Toast.makeText(MainActivity.this, e.toString(), Toast.LENGTH_LONG).show();
}
// swipeLayout.setRefreshing(false);
return true;
}
#Override
public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
swipeLayout.setRefreshing(false);
Log.d("onReceivedSslError", "onReceivedSslError");
//super.onReceivedSslError(view, handler, error);
}
}
#Override
public void onBackPressed() {
if (mWebview.canGoBack()) {
mWebview.goBack();
} else {
finish();
}
}
class UriChromeClient extends WebChromeClient {
#Override
public boolean onCreateWindow(WebView view, boolean isDialog,
boolean isUserGesture, Message resultMsg) {
mWebviewPop = new WebView(getApplicationContext());
mWebviewPop.setVerticalScrollBarEnabled(false);
mWebviewPop.setHorizontalScrollBarEnabled(false);
mWebviewPop.setWebViewClient(new UriWebViewClient());
mWebviewPop.getSettings().setJavaScriptEnabled(true);
mWebviewPop.getSettings().setSavePassword(false);
mWebviewPop.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT));
mContainer.addView(mWebviewPop);
WebView.WebViewTransport transport = (WebView.WebViewTransport) resultMsg.obj;
transport.setWebView(mWebviewPop);
resultMsg.sendToTarget();
return true;
}
#Override
public void onCloseWindow(WebView window) {
Log.d("onCloseWindow", "called");
}
}
}
I'm gonna go out on a limb here and say you are doing IO operations (like trying to login by sending credentials over the internet) on the main UI thread. If this is the case, this is what is causing your app to freeze.
I couldn't find the actual code that is responsible for the login, but, if you are sending an HTTP request or something similar to it, you need to do it in a background thread, so that UI doesn't freeze.
The main thread in Android is responsible for updating the UI, and if you block it with a blocking IO operation, it will freeze.
On this page: https://developer.android.com/training/app-links/deep-linking, in the
'Read data from incoming intents'
section, Google mentions:
Once the system starts your activity through an intent filter, you can
use data provided by the Intent to determine what you need to render.
Call the getData() and getAction() methods to retrieve the data and
action associated with the incoming Intent.
And that's exactly what I'm trying to do, but, I'm unable to get help.
In this activity of mine:
package com.application;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
#SuppressWarnings("unused")
public class SplashActivity3 extends Activity
{
Handler Handler;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash3);
Handler = new Handler();
Handler.postDelayed(new Runnable()
{
#Override
public void run()
{
Intent intent = new Intent(SplashActivity3.this, MainActivity.class);
startActivity(intent);
finish();
}
},
1500);
Intent appLinkIntent = getIntent();
String appLinkAction = appLinkIntent.getAction();
Uri appLinkData = appLinkIntent.getData();
}
}
I want to know (later tranfer it to another activity), the URL that was clicked on to open my app.
Basically, my app is using App Links (referred to as Deep Linking by some). So, in a case where a user 'A', sends user 'B' a link of a page on my website and B has my app installed, he/she will be able to open the link in my app instead of the browser.
As of now, B can open the link in my app, but, my app will always load the 'home page' (it's because I have coded my app to open the home page by default). I want to load the page that brought B in my app.
For a real life example, just like Facebook's app does. Suppose I share a link of a Facebook page or a profile to my friend. It's a standard HTTP link that's displayed in my web browser. Probably, I shared it with him on WhatsApp. He touches the link to open it. He has the official Facebook app installed on his phone. So, Android asks him if he wants to open the link in the Facebook app or in the browser. Now, when he chooses the browser, it's no problem at all. But, when he chooses the Facebook app, the app loads the profile or the page that exists on the link and not the home page of Facebook. That's what I want to achieve.
Please note, I'm talking about standard HTTP links here and not my app specific URIs.
UPDATE:
Here's something I tried now:
This is the same activity as above, I modified it like this:
package com.application;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
#SuppressWarnings("unused")
public class SplashActivity3 extends Activity
{
Handler Handler;
#Override
protected void onCreate(Bundle savedInstanceState)
{
final Intent appLinkIntent = getIntent();
final String appLinkAction = appLinkIntent.getAction();
Uri appLinkData = appLinkIntent.getData();
final Bundle bundle = new Bundle();
bundle.putString("web", appLinkAction);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash3);
Handler = new Handler();
Handler.postDelayed(new Runnable()
{
#Override
public void run()
{
Intent intent = new Intent(SplashActivity3.this, WebViewActivity.class);
intent.putExtras(bundle);
startActivity(intent);
finish();
}
},
1500);
}
}
And the activity in which I'm loading the URL:
package com.application;
import android.annotation.SuppressLint;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.net.Uri;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.webkit.WebChromeClient;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.Toast;
#SuppressWarnings("deprecation")
public class WebViewActivity extends AppCompatActivity
{
private WebView WebView;
private ProgressBar ProgressBar;
private LinearLayout LinearLayout;
private String currentURL;
#SuppressLint("SetJavaScriptEnabled")
#Override
protected void onCreate(Bundle savedInstanceState)
{
WebView wv = new WebView(this);
wv.loadUrl("file:///android_asset/eula.html");
wv.getSettings().setJavaScriptEnabled(true);
wv.getSettings().setUserAgentString("customUA");
wv.setWebViewClient(new WebViewClient()
{
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url3)
{
view.loadUrl(url3);
return true;
}
});
final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
boolean agreed = sharedPreferences.getBoolean("agreed",false);
if(!agreed)
{
new AlertDialog.Builder(this, R.style.AlertDialog)
.setIcon(R.drawable.ic_remove_circle_black_24dp)
.setTitle(R.string.eula_title)
.setView(wv)
.setCancelable(false)
.setPositiveButton(R.string.accept, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean("agreed", true);
editor.apply();
}
})
.setNegativeButton(R.string.decline, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
finish();
}
})
.show();
}
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView = findViewById(R.id.webView5);
ProgressBar = findViewById(R.id.progressBar5);
LinearLayout = findViewById(R.id.layout5);
ProgressBar.setMax(100);
Bundle bundle = getIntent().getExtras();
String url = bundle.getString("web");
WebView.loadUrl(R.string.url);
WebView.getSettings().setJavaScriptEnabled(true);
WebView.getSettings().setUserAgentString("customUA");
WebView.setWebViewClient(new WebViewClient()
{
#Override
public void onPageStarted(WebView view, String url, Bitmap favicon)
{
LinearLayout.setVisibility(View.VISIBLE);
super.onPageStarted(view, url, favicon);
}
#Override
public void onPageFinished(WebView view, String url)
{
LinearLayout.setVisibility(View.GONE);
super.onPageFinished(view, url);
currentURL = url;
}
#Override
public void onReceivedError(WebView webview, int i, String s, String s1)
{
WebView.setVisibility(View.GONE);
Intent intent = new Intent(WebViewActivity.this, ErrorActivity.class);
startActivity(intent);
finish();
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url2)
{
if (url2.contains("www.mydomain.tld"))
{
view.loadUrl(url2);
return false;
} else
{
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url2));
startActivity(intent);
return true;
}
}
});
WebView.setWebChromeClient(new WebChromeClient()
{
#Override
public void onProgressChanged(WebView view, int newProgress)
{
super.onProgressChanged(view, newProgress);
ProgressBar.setProgress(newProgress);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu)
{
super.onPrepareOptionsMenu(menu);
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.menu, menu);
return super.onCreateOptionsMenu(menu);
}
#SuppressLint("SetJavaScriptEnabled")
#Override
public boolean onOptionsItemSelected(MenuItem item)
{
switch (item.getItemId())
{
case R.id.backward:
onBackPressed();
break;
case R.id.forward:
onForwardPressed();
break;
case R.id.refresh:
WebView.reload();
break;
case R.id.share:
Intent shareIntent = new Intent(Intent.ACTION_SEND);
shareIntent.setType("text/plain");
shareIntent.putExtra(Intent.EXTRA_TEXT,currentURL);
startActivity(Intent.createChooser(shareIntent, getResources().getText(R.string.shareWith)));
break;
case R.id.update:
Intent intent = new Intent(WebViewActivity.this, UpdateActivity.class);
startActivity(intent);
finish();
break;
case R.id.about:
WebView wv2 = new WebView(this);
wv2.loadUrl("file:///android_asset/about.html");
wv2.getSettings().setJavaScriptEnabled(true);
wv2.getSettings().setUserAgentString("customUA");
wv2.setWebViewClient(new WebViewClient()
{
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url4)
{
view.loadUrl(url4);
return true;
}
});
new AlertDialog.Builder(this, R.style.AlertDialog)
.setIcon(R.drawable.ic_info_black_24dp)
.setTitle(R.string.info)
.setView(wv2)
.setPositiveButton(R.string.okay, null)
.show();
break;
case R.id.exit:
new AlertDialog.Builder(this,R.style.AlertDialog)
.setIcon(R.drawable.ic_error_black_24dp)
.setTitle(R.string.title)
.setMessage(R.string.message)
.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
finish();
}
})
.setNegativeButton(R.string.no, null)
.show();
break;
}
return super.onOptionsItemSelected(item);
}
private void onForwardPressed()
{
if (WebView.canGoForward())
{
WebView.goForward();
} else
{
Toast.makeText(this, R.string.noFurther, Toast.LENGTH_SHORT).show();
}
}
#Override
public void onBackPressed ()
{
if (WebView.canGoBack())
{
WebView.goBack();
} else
{
new AlertDialog.Builder(this,R.style.AlertDialog)
.setIcon(R.drawable.ic_error_black_24dp)
.setTitle(R.string.title)
.setMessage(R.string.message)
.setPositiveButton(R.string.yes,
new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
finish();
}
})
.setNegativeButton(R.string.no, null)
.show();
}
}
}
But, I'm getting Cannot resolve symbol url error at WebView.loadUrl(R.string.url);
What to do?
Can anyone please help me check my code to see why it cannot be
launched in the app itself but directs me to a browser? ): Thanks!!
MAIN ACTIVITY.JAVA
package com.intelligami.androidwebviewapp;
import android.app.ActionBar;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.widget.ShareActionProvider;
public class MainActivity extends Activity {
private WebView mWebView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mWebView = (WebView) findViewById(R.id.activity_main_webview);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mWebView.loadUrl("http://intelligami.com/submitqn");
mWebView.setWebViewClient(new com.intelligami.androidwebviewapp.MyAppWebViewClient(){
#Override
public void onPageFinished(WebView view, String url) {
//hide loading image
findViewById(R.id.progressBar1).setVisibility(View.GONE);
//show webview
findViewById(R.id.activity_main_webview).setVisibility(View.VISIBLE);
}});
}
private class MyWebViewClient extends MyAppWebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
#Override
public void onBackPressed() {
if(mWebView.canGoBack()) {
mWebView.goBack();
} else {
super.onBackPressed();
}
}
private ShareActionProvider mShareActionProvider;
#Override
public boolean onCreateOptionsMenu(Menu menu) {
/** Inflating the current activity's menu with res/menu/items.xml */
getMenuInflater().inflate(R.menu.menu_main, menu);
/** Getting the actionprovider associated with the menu item whose id is share */
mShareActionProvider = (ShareActionProvider) menu.findItem(R.id.share).getActionProvider();
/** Setting a share intent */
mShareActionProvider.setShareIntent(getDefaultShareIntent());
return super.onCreateOptionsMenu(menu);
}
/** Returns a share intent */
private Intent getDefaultShareIntent(){
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setType("text/plain");
intent.putExtra(Intent.EXTRA_SUBJECT, "Convert Website to Android Application");
intent.putExtra(Intent.EXTRA_TEXT," Vist www.AndroidWebViewApp.com if you Want to Convert your Website or Blog to Android Application");
return intent;
}
}
MY APP VIEW CLIENT. JAVA
package com.intelligami.androidwebviewapp;
import android.content.Intent;
import android.net.Uri;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MyAppWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if(Uri.parse(url).getHost().endsWith("intelligami.com/submitqn")) {
return false;
}
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
view.getContext().startActivity(intent);
return true;
}
}
Where is the error? :D
It keeps opening up in the browser.
In the following line:
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
you're asking Android to open a URL using the intent constant ACTION_VIEW - so it defaults to the external browser.
Here a full example (taken from here) that shows how to open the url using a WebViewClient:
package com.paresh.webviewclientdemo;
import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.KeyEvent;
import android.webkit.WebView;
import android.webkit.WebViewClient;
/*
* Demo of creating an application to open any URL inside the application and clicking on any link from that URl
should not open Native browser but that URL should open in the same screen.
*/
public class WebViewClientDemoActivity extends Activity {
/** Called when the activity is first created. */
WebView web;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
web = (WebView) findViewById(R.id.webview01);
web.setWebViewClient(new myWebClient());
web.getSettings().setJavaScriptEnabled(true);
web.loadUrl("http://www.google.com");
}
public class myWebClient extends WebViewClient
{
#Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
// TODO Auto-generated method stub
super.onPageStarted(view, url, favicon);
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
// TODO Auto-generated method stub
view.loadUrl(url);
return true;
}
}
// To handle "Back" key press event for WebView to go back to previous screen.
#Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK) && web.canGoBack()) {
web.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
}
I am trying to add a back button to app but when i add the code i get the "Non static method 'canGoBack() cannot be referenced from a static context" error. I have read several stack articles about this error but have not been able to solve it. Any ideas please?
package com.test;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.Toast;
import com.parse.ParseInstallation;
import com.parse.ParsePush;
import com.parse.ParseQuery;
import com.parse.PushService;
public class MainActivity extends Activity implements OnClickListener {
private Button push;
private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(getApplicationContext(), "onReceive invoked!", Toast.LENGTH_LONG).show();
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PushService.setDefaultPushCallback(this, MainActivity.class);
Button back = (Button) findViewById(R.id.back);
WebView webView = (WebView) findViewById(R.id.webView1);;
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl("http://www.xxxxx.xxxxxx.xxxxx.xxxx// ");
webView.setWebViewClient(new WebViewClient());
push = (Button)findViewById(R.id.senPushB);
push.setOnClickListener(this);
}
private class Callback extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
return (true);
}
}
#Override
public void onBackPressed()
{
if(WebView.canGoBack()){
WebView.goBack();
}else{
super.onBackPressed();
}
}
#Override
public void onPause() {
super.onPause();
LocalBroadcastManager.getInstance(this).unregisterReceiver(mBroadcastReceiver);
}
#Override
public void onResume() {
super.onResume();
LocalBroadcastManager.getInstance(this).registerReceiver(mBroadcastReceiver, new IntentFilter(MyCustomReceiver.intentAction));
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
#Override
public void onClick(View v) {
JSONObject obj;
try {
obj = new JSONObject();
obj.put("alert", "hello!");
obj.put("action", MyCustomReceiver.intentAction);
obj.put("customdata","My message");
ParsePush push = new ParsePush();
ParseQuery query = ParseInstallation.getQuery();
// Push the notification to Android users
query.whereEqualTo("deviceType", "android");
push.setQuery(query);
push.setData(obj);
push.sendInBackground();
} catch (JSONException e) {
e.printStackTrace();
}
}
}
Try changing:
#Override
public void onBackPressed()
{
if(WebView.canGoBack()){
WebView.goBack();
}else{
super.onBackPressed();
}
}
to:
#Override
public void onBackPressed()
{
WebView webView = (WebView) findViewById(R.id.webView1);
if(webView.canGoBack()){
webView.goBack();
}else{
super.onBackPressed();
}
}
Explanation:
You should call canGoBack() and goBack() for the webview instance that you're using (move to the previous view). This is also why the method is declared at the instance level and not at the class level (static)
canGoBack is an instance (non-static) method. It can only be called on an instance of the WebView class. WebView is the class. Calling WebView.function() only works if function is a static function. You need to get the instance of the WebView and call it on that.
For the record, the difference between a static and instance method- a static method may not use any non-static data. An instance method can. Static data only has 1 copy per class. Non-static data has 1 copy per instance of the class.
I'm using the following code to display a webview in my Android app.
package com.company.myapp;
import com.google.android.apps.analytics.GoogleAnalyticsTracker;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class ArticlesActivity extends Activity {
/** Initialize the Google Analytics Tracker */
GoogleAnalyticsTracker tracker;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().requestFeature(Window.FEATURE_PROGRESS);
getWindow().setFeatureInt(Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
WebView webview = new WebView(this);
setContentView(webview);
setProgressBarVisibility(true);
webview.getSettings().setJavaScriptEnabled(true);
webview.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
final Activity activity = this;
tracker = GoogleAnalyticsTracker.getInstance();
// Start the tracker, updating google every 20 seconds
tracker.start((String) getText(R.string.analyticsID), 20, this);
webview.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
activity.setProgress(progress * 100 );
}
});
webview.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
webview.loadUrl("http://www.google.com");
}
#Override
public void onResume() {
tracker.trackPageView("ArticlesActivity");
super.onResume();
}
#Override
protected void onDestroy() {
super.onDestroy();
// Stop the tracker when it is no longer needed.
tracker.stop();
}
}
I would need to enable the back button to step back if history exists instead of just exiting the webview.
I've tried many different code examples such as this but can't get any to work. The app just shuts down when the back button is pressed.
Here's my code with the back button code but it just crashes the app when then back button is pressed:
package com.company.myapp;
import com.google.android.apps.analytics.GoogleAnalyticsTracker;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class ArticlesActivity extends Activity {
WebView webview;
/** Initialize the Google Analytics Tracker */
GoogleAnalyticsTracker tracker;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().requestFeature(Window.FEATURE_PROGRESS);
getWindow().setFeatureInt(Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
WebView webview = new WebView(this);
setContentView(webview);
setProgressBarVisibility(true);
webview.getSettings().setJavaScriptEnabled(true);
webview.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
final Activity activity = this;
tracker = GoogleAnalyticsTracker.getInstance();
// Start the tracker, updating google every 20 seconds
tracker.start((String) getText(R.string.analyticsID), 20, this);
webview.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
activity.setProgress(progress * 100 );
}
});
webview.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
webview.loadUrl("http://www.google.com");
}
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
webview.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
#Override
public void onResume() {
tracker.trackPageView("ArticlesActivity");
super.onResume();
}
#Override
protected void onDestroy() {
super.onDestroy();
// Stop the tracker when it is no longer needed.
tracker.stop();
}
}
Could someone help me with a solution?
Got it! Your problem in this line
WebView webview = new WebView(this);
Instead of using your member variable you are creating a variable inside function, and hence your member variable is null inside onKeyDown function.
Just replace it with
webview = new WebView(this);