Basic webview app problems

Basic webview app problems - android

I am trying to make a basic webview application, but it's giving 4 errors.
Error:(35, 9) error: method does not override or implement a method
from a supertype
Error:(46, 32) error: non-static method canGoBack() cannot be
referenced from a static context
Error:(47, 32) error: non-static method goBack() cannot be referenced
from a static context
Error:Execution failed for task ':app:compileDebugJava'.
Compilation failed; see the compiler error output for details.
Can anyone tell me what's wrong with my code?
Here's my code:
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.Window;
import android.view.WindowManager;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
setContentView(R.layout.activity_main);
WebView mainWebView = (WebView) findViewById(R.id.mainWebView);
WebSettings webSettings = mainWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mainWebView.setWebViewClient(new MyCustomWebViewClient());
mainWebView.loadUrl("http://facebook.com/");
}
private class MyCustomWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (WebView.canGoBack()) {
WebView.goBack();
} else {
finish();
}
return true;
}
}
}
}
This is my new code now with your help which shows no errors, but still doesn't work(Failed to complete gradle execution, when I try to run it in the emulator):
public class MainActivity extends ActionBarActivity {
private WebView mainWebView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
setContentView(R.layout.activity_main);
mainWebView = (WebView) findViewById(R.id.mainWebView);
WebSettings webSettings = mainWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mainWebView.setWebViewClient(new MyCustomWebViewClient());
mainWebView.loadUrl("http://facebook.com/");
}
private class MyCustomWebViewClient extends WebViewClient {
public boolean shouldOvrrideLoading (WebView view, String url) {
view.loadUrl(url);
return true;
}
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (mainWebView.canGoBack()) {
mainWebView.goBack();
} else {
finish();
}
return true;
}
}
return false;
}
}

The error actually explains what is wrong:
"non-static method goBack() cannot be referenced from a static context"
You need to replace the static WebView.canGoBack() with your instantiated webview mainWebView.canGoBack()
The same applies for WebView.goBack()

mainWebView variable should be object of class MainActivity
public class MainActivity extends ActionBarActivity {
private WebView mainWebView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
setContentView(R.layout.activity_main);
mainWebView = (WebView) findViewById(R.id.mainWebView);
WebSettings webSettings = mainWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mainWebView.setWebViewClient(new MyCustomWebViewClient());
mainWebView.loadUrl("http://facebook.com/");
}
private class MyCustomWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (mainWebView.canGoBack()) {
mainWebView.goBack();
} else {
finish();
}
return true;
}
}
}
}

Related

Want to implement back button functionality to a basic Android WebView application

I created a basic WebView app, want to add a back button function which would take the user to the previous page rather than exiting the app. Have attached the MainActivity.java code with this question below.I am a newbie to stack overflow and android development.
package example.com;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends AppCompatActivity {
private 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 WebViewClient());
webview.getSettings().setJavaScriptEnabled(true);
webview.getSettings().setDomStorageEnabled(true);
webview.setOverScrollMode(WebView.OVER_SCROLL_NEVER);
webview.loadUrl("https://www.example.com");
}
}

#Override onBackPress() inside your mainActivity and add your navigation logic inside it. Here is working snipped
public class MainActivity extends AppCompatActivity {
private WebView webView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
webView = findViewById(R.id.webView);
webView = new WebView(MainActivity.this);
webView.loadUrl(...);
}
#Override
public void onBackPressed() {
if (webView != null && webView.canGoBack()) {
webView.goBack();
}else{
//Your App exit logic here
}
}
}
I hope this will meet your requirements.

Try this, hope this helps
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (mWebView.canGoBack()) {
mWebView.goBack();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}

Go back to previous page one back key press Android WebView Fragment

I am using Navigation drawer activity and have 5 fragments, each and every fragment uses WebView to open webpage. Before I was using just one MainActivity which just opened one site and was able to go back to previous opened page easily but now I can't find anything that will let me do this. I am using this code currently in my fragments, I am using the code to go back from here and whenever I open a fragment, app just force-closes.
package com.science.s11;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
public class ask extends Fragment {
public WebView mWebView;
public ProgressBar progressBar;
public LinearLayout layoutProgress;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.ampproject, container, false);
mWebView = (WebView) v.findViewById(R.id.aboutuswebViewask);
progressBar = (ProgressBar) v.findViewById(R.id.progressBarask);
layoutProgress = (LinearLayout) v.findViewById(R.id.layoutProgressask);
mWebView.setVisibility(View.GONE);
mWebView.setOnKeyListener(new View.OnKeyListener()
{
#Override
public boolean onKey(View v, int keyCode, KeyEvent event)
{
if(event.getAction() == KeyEvent.ACTION_DOWN)
{
WebView webView = (WebView) v;
switch(keyCode)
{
case KeyEvent.KEYCODE_BACK:
if(webView.canGoBack())
{
webView.goBack();
return true;
}
break;
}
}
return false;
}
});
mWebView.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mWebView.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
WebSettings settings = mWebView.getSettings();
settings.setSupportMultipleWindows(true);
settings.setBuiltInZoomControls(false);
settings.setSupportZoom(false);
settings.setDisplayZoomControls(false);
mWebView.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
#Override
public void onPageFinished(WebView view, String url) {
mWebView.setVisibility(View.VISIBLE);
layoutProgress.setVisibility(View.GONE);
progressBar.setIndeterminate(true);
super.onPageFinished(view, url);
}
#Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
layoutProgress.setVisibility(View.VISIBLE);
progressBar.setIndeterminate(false);
super.onPageStarted(view, url, favicon);
}
});
if (isOnline()) {
mWebView.loadUrl("http://google.com");
} else {
mWebView.loadUrl("file:///android_asset/cti.html");
}
return v;
}
public boolean isOnline() {
ConnectivityManager cm = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
return (netInfo != null && netInfo.isConnected());
}}
Can you guys please help me?

Try this, its simple and works fine.
In all of your 5 Fragments, set the variable to public static:
public static WebView mWebView;
In your Mainactivity:
#Override
public void onBackPressed() {
if (Fragment_1.mWebView!= null) {
if (Fragment_1.mWebView.canGoBack()) {
Fragment_1.mWebView.goBack();
} else {
// do when mWebView cant go back anymore
}
}
if (Fragment_2.mWebView!= null){
if (Fragment_2.mWebView.canGoBack()) {
Fragment_2.mWebView.goBack();
} else {
// do when mWebView cant go back anymore
}
}
if (Fragment_3.mWebView!= null){
if (Fragment_3.mWebView.canGoBack()) {
Fragment_3.mWebView.goBack();
} else {
// do when mWebView cant go back anymore
}
}
if (Fragment_4.mWebView!= null){
if (Fragment_4.mWebView.canGoBack()) {
Fragment_4.mWebView.goBack();
} else {
// do when mWebView cant go back anymore
}
}
//and so on......
}

Try this:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (mWebView.canGoBack()) {
mWebView.goBack();
} else {
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}

you can make a base fragment like this
public abstract class BaseFragments extends Fragment {
abstract public int setContentView();
public void replaceFragment(Context context, Fragment fragment) {
((BaseActivity) context).getSupportFragmentManager().beginTransaction()
.replace(R.id.container, fragment).commit();
}
#Override
public void onResume() {
super.onResume();
// preferencesUtility.setuserData(context, userdata);
getView().setFocusableInTouchMode(true);
getView().requestFocus();
getView().setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_UP
&& keyCode == KeyEvent.KEYCODE_BACK) {
// Toast.makeText(context, "clicked", Toast.LENGTH_LONG)
// .show();
backPressed();
return true;
}
return false;
}
});
}
protected abstract void backPressed();
}
and override onBackPressed()in your fragment something like this
public class TestFragment extends BaseFragments {
#Override
public int setContentView() {
return R.layout.weblayout;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.weblayout, container, false);
cabmoneyview = (WebView) rootView.findViewById(R.id.webview);
return rootView;
}
#Override
protected void backPressed() {
// TODO Auto-generated method stub
}
}

webview back button stopped

In my webview app if I press the back button I get an error:
unfortunately app has stopped
I've tried 2 different ways of doing the back button. Am I missing something?
P.s. first app so please bear with me
package au.com.industryresponsetraining.mdt;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends AppCompatActivity {
private WebView mwebview;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String "http://www.google.com";
WebView mwebview = (WebView) this.findViewById(R.id.webView);
mwebview.getSettings().setJavaScriptEnabled(true);
mwebview.loadUrl(url);
mwebview.setWebViewClient(new WebViewClient());
}
private class MyWebviewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (Uri.parse(url).getHost().equals("http://www.google.com")) {
return false;
} else {
//here open external links in external browser or app
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(intent);
return true;
}
}
}
//back button function thats not working
#Override
public void onBackPressed() {
if (mwebview.canGoBack()) {
mwebview.goBack();
} else {
super.onBackPressed();
}
}
}

your onCreate method should be
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String "http://www.google.com";
mwebview = (WebView) this.findViewById(R.id.webView);
}
instead of
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String "http://www.google.com";
WebView mwebview = (WebView) this.findViewById(R.id.webView);
}

Try this:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (mwebview.canGoBack()) {
mwebview.goBack();
} else {
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}

backbutton on my android webview

I tried to add a back button to my android webview but i've got this error:
The method onBackPressed() of type new WebViewClient(){} must override or implement a supertype method
This is my Java file:
package sherdle.donald.duck.app;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class WebPageLoader extends Activity
{
WebView webview;
final Activity activity = this;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
setContentView(R.layout.main);
WebView webView = (WebView) findViewById(R.id.webview);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress)
{
activity.setTitle("Loading...");
activity.setProgress(progress * 100);
if(progress == 100)
activity.setTitle(R.string.app_name);
}
});
webView.setWebViewClient(new WebViewClient() {
#Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
{
// Handle the error
}
#Override
public void onBackPressed() {
// do something on back.
return;
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
});
webView.loadUrl("http://example.com");
}
}
Thanks for your help.

According to the doc, there is no onBackPressed method in the WebViewClient class. Did you want to Override it on your activity ?
try smthing like this:
package sherdle.donald.duck.app;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class WebPageLoader extends Activity
{
WebView webView;
final Activity activity = this;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
setContentView(R.layout.main);
webView = (WebView) findViewById(R.id.webview);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress)
{
activity.setTitle("Loading...");
activity.setProgress(progress * 100);
if(progress == 100)
activity.setTitle(R.string.app_name);
}
});
webView.setWebViewClient(new WebViewClient() {
#Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
{
// Handle the error
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
});
webView.loadUrl("http://example.com");
}
#Override
public void onBackPressed (){
if(webView.canGoBack()) webView.goBack();
else super.onBackPressed();
}
}

You have to override the onkeyDown() method in your Activity.
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(event.getAction() == KeyEvent.ACTION_DOWN){
switch(keyCode)
{
case KeyEvent.KEYCODE_BACK:
if(mWebView.canGoBack() == true){
mWebView.goBack();
}else{
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}

Try this
package sherdle.donald.duck.app;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class WebPageLoader extends Activity
{
WebView webview;
final Activity activity = this;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
setContentView(R.layout.main);
webView = (WebView) findViewById(R.id.webview);
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl("http://example.com");
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress)
{
activity.setTitle("Loading...");
activity.setProgress(progress * 100);
if(progress == 100)
activity.setTitle(R.string.app_name);
}
});
webView.setWebViewClient(new WebViewClient() {
#Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
{
// Handle the error
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
});
}
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if(mWebView.canGoBack() == true)
webview.goBack();
else finish();
break;
default:
break;
}
return super.onKeyDown(keyCode, event);
}
}
And this method should be override in Activty.

WebView webView = (WebView) findViewById(R.id.webview);
Change it to:
webView = (WebView) findViewById(R.id.webview);
and then use the second answer - works like a charm!

Back button in an android webview?

I'm having trouble getting the hardware back key on an android phone to work with a webView. The following is the code I'm using. Every time I run the app it force closes.
package com.knowideas.transithub;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.KeyEvent;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class WebViewDemo extends Activity {
private static final String LOG_TAG = "WebViewDemo";
private WebView mWebView;
private Handler mHandler = new Handler();
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
// Check if the key event was the BACK key and if there's history
if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
mWebView.goBack();
return true;
}
// If it wasn't the BACK key or there's no web page history, bubble up to the default
// system behavior (probably exit the activity)
return super.onKeyDown(keyCode, event);
}
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
mWebView = (WebView) findViewById(R.id.webView);
WebSettings webSettings = mWebView.getSettings();
webSettings.setSavePassword(false);
webSettings.setSaveFormData(false);
webSettings.setJavaScriptEnabled(true);
webSettings.setSupportZoom(false);
mWebView.setWebChromeClient(new WebChromeClient());
mWebView.addJavascriptInterface(new DemoJavaScriptInterface(), "demo");
mWebView.loadUrl("file:///android_asset/demo.html");
}
final class DemoJavaScriptInterface {
DemoJavaScriptInterface() {
}
/**
* This is not called on the UI thread. Post a runnable to invoke
* loadUrl on the UI thread.
*/
public void clickOnAndroid() {
mHandler.post(new Runnable() {
public void run() {
mWebView.loadUrl("javascript:wave()");
}
});
}
}
}

Here's my guess:
Your trying to catch the key event too late. You need to grab it before it gets to the webview. You do that by setting an onKeyListener.
here's how:
mWebView.setOnKeyListener(new OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
// ignore the back key
return true;
}
// process normally
return false;
}
});
I can't to do more that just 'block' it -- and that's what I'm trying to find out in another question.
Best
-Yaakov

ON BACK PRESSED
//So links stay inside webview
webview.setWebViewClient(new WebViewClient());
webview.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View view, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
WebView webView = (WebView) view;
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (webView.canGoBack()) {
webView.goBack();
return true;
}
break;
}
}
return false;
}
});

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

Basic webview app problems - android

The error actually explains what is wrong: "non-static method goBack() cannot be referenced from a static context" You need to replace the static WebView.canGoBack() with your instantiated webview mainWebView.canGoBack() The same applies for WebView.goBack()

Related

Want to implement back button functionality to a basic Android WebView application

Go back to previous page one back key press Android WebView Fragment

webview back button stopped

backbutton on my android webview

Back button in an android webview?

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