How to control navigation history in webview inside fragment

How to control navigation history in webview inside fragment - android

I have a webview inside fragment and I want it to be controlled by the navigation history whenever I press the back button.
In my case, when I press the back button I leave the webview, but I want that on pressing the button I will return to the state that is stored in the navigation history (from before leaving the webview).
Any solution please?
I tried with onKey but it does not resolve my problem. Here my code:
public class FragmentAll extends Fragment implements
DialogInterface.OnCancelListener, DialogInterface.OnDismissListener,
OnDownloaExpodTerminated {
public static Fragment newInstance(Context context) {
FragmentAll f = new FragmentAll();
return f;
}
private WebView myWebView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
(((MainActivity) getActivity()) ).setActionBarTitle("Store");
myWebView = (WebView) v.findViewById(R.id.webView1);
setWebview();
v.setOnKeyListener(new OnKeyListener() {
#Override
public boolean onKey(View arg0, int arg1, KeyEvent arg2) {
// TODO Auto-generated method stub
if (arg1 == KeyEvent.KEYCODE_BACK && myWebView.canGoBack()) {
myWebView.goBack();
return true;
}
return false;
}
});
return v;
}
...
}

You can try it
#Override
public void onBackPressed() {
if (mWebView.canGoBack()) {
mWebView.goBack();
return;
}
// Otherwise defer to system default behavior.
super.onBackPressed();
}

You will have to make a method inside your Fragment class:
public void goBackWebview(){
myWebview.goBack();
}
Now, go to the Activity class to which this fragment is attached and override the onBackPressed():
#Override
public void onBackPressed() {
//if webview has history
myFragment.goBackWebView();
}

you need to manage list of links is loaded in your webview.
you can get the url like this
web_des2.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
HitTestResult hitTestResult = web_des2.getHitTestResult();
if (hitTestResult != null) {
String url = hitTestResult.getExtra();
if (url != null && url.startsWith("http://")) {
yourUrlList.add(url);
web_des2.loadUrl(url);
}
}
return true;
}
return false;
}
});
you can check onBackPress if your list does not empty then get url form list and load it into webview and remove from the list.
you can use Stack to store url so become easy you can use pop() and push() function directly. if like than +1

Related

Clicking Android phone's "go back" button didn't return to the parent view from a webview

I developed an android app which has a list view as its main gui, when the user click the item in the list, a webview will show basing on the content of the item.
It works fine, however when I clicked the back button in the android phone (or simulator), a blank white screen is shown, and the list view appears only after I click the back button again.
Can anyone help explain and help solve the problem?
Here is my WebviewActivity :
public class WebViewActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.active_item_detail);
if (savedInstanceState == null) {
WebViewFragment wvf = new WebViewFragment();
Intent i = this.getIntent();
wvf.init(i.getExtras());
getFragmentManager().beginTransaction().add(R.id.webview, wvf).commit();
}
}
}
and WebviewFragment:
public class WebViewFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.active_item_detail, container, false);
WebView wv = (WebView) v.findViewById(R.id.webview);
wv.getSettings().setJavaScriptEnabled(true);
//data is the content
if(data!=null) {
wv.loadData(data, "text/html", "UTF-8");
}
return v;
}
}
The layout file is like:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical">
<WebView android:id="#+id/webview"
android:layout_height="match_parent"
android:layout_width="wrap_content"
tools:context="com.mycompany.myapp.WebViewFragment" />
</LinearLayout>

private void emulateShiftHeld(){
try
{
KeyEvent shiftPressEvent = new KeyEvent(0, 0,
KeyEvent.ACTION_DOWN,KeyEvent.KEYCODE_SHIFT_LEFT, 0, 0);
System.out.println(“shift press:::”+shiftPressEvent.dispatch(view));
}
catch (Exception e){
Log.e(“dd”, “Exception in emulateShiftHeld()”, e);
}
refer to this link https://harshdevchandel.wordpress.com/2013/05/13/android-webview-selection/
check if back is pressed finish this activity
How to handle back button in activity

If a part of your application is contained in a WebView, it may be appropriate for Back to traverse browser history.
#Override
public void onBackPressed() {
if (mWebView.canGoBack()) {
mWebView.goBack();
return;
}
// Otherwise defer to system default behavior.
super.onBackPressed();
}
It is documented in the official docs here
http://developer.android.com/training/implementing-navigation/temporal.html#back-webviews

Try this way:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (wv.canGoBack()) {
wv.goBack();
} else {
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}
Also, you try with:
#Override
public void onBackPressed() {
Fragment webviewFragment = getSupportFragmentManager().findFragmentByTag("webview");
if (webview instanceof WebViewFragment) {
boolean goback = ((WebViewFragment)webview).canGoBack();
if (!goback)
super.onBackPressed();
}
}

Thanks to all. Unfortunately I couldn't make it after trying all suggestions above. I resolved the problem by creating an intent inside the onBackPressed() hook, and start the initial activity.

Fragment keyListener not working

I am trying to finish my activity from fragment BackPressed.But the Key Listener is not at all get called.I have searched but its about the EditText problem most of the time.Below is my code:
public class ProductFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.product_fragment, container,false);
view.setOnKeyListener( new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
// TODO Auto-generated method stub
if (keyCode == KeyEvent.KEYCODE_BACK) {
getActivity().finish();
return true;
}
return false;
}
});
}

Maybe you can just override the onBackPressed() on the holding Activity. It will give the result you're looking for. Check it out: http://developer.android.com/reference/android/app/Activity.html#onBackPressed()

How to add "Go Back" function in WebView inside Fragment?

UPDATE: Solved! Problem was related to my Viewpager not WebView.
I'm trying to add a "Go Back" function to my WebView which is inside a Fragment. But I can't figure out how to:
public final class TestFragment extends Fragment {
static WebView mWeb;
private View mContentView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
mContentView = inflater.inflate(R.layout.webview, null);
mWeb = (WebView)mContentView.findViewById(R.id.webview);
WebSettings settings = mWeb.getSettings();
settings.setJavaScriptEnabled(true);
settings.setSupportZoom(false);
mWeb.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
mWeb.getSettings().setBuiltInZoomControls(false);
mWeb.loadUrl("myurl...");
mWeb.setOnKeyListener(new OnKeyListener(){
public boolean onKey(View v, int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && mWeb.canGoBack()) {
mWeb.goBack();
return true;
}
return false;
}
});
}
}
I also tried something like:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && mWeb.canGoBack()) {
mWeb.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
Another solution but same problem:
#Override
public void onBackPressed()
{
if(webView.canGoBack())
webView.goBack();
else
super.onBackPressed();
}
Any ideas how to get this working?

Perhaps its android restriction. Try to do this using handler.
public final class TestFragment extends Fragment {
static WebView mWeb;
private View mContentView;
private Handler handler = new Handler(){
#Override
public void handleMessage(Message message) {
switch (message.what) {
case 1:{
webViewGoBack();
}break;
}
}
};
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
mContentView = inflater.inflate(R.layout.webview, null);
mWeb = (WebView)mContentView.findViewById(R.id.webview);
WebSettings settings = mWeb.getSettings();
settings.setJavaScriptEnabled(true);
settings.setSupportZoom(false);
mWeb.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
mWeb.getSettings().setBuiltInZoomControls(false);
mWeb.loadUrl("myurl...");
mWeb.setOnKeyListener(new OnKeyListener(){
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.getAction() == MotionEvent.ACTION_UP
&& mWeb.canGoBack()) {
handler.sendEmptyMessage(1);
return true;
}
return false;
}
});
}
private void webViewGoBack(){
mWeb.goBack();
}
}

You can check this code :
webView.canGoBack();
webView.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.getAction() == MotionEvent.ACTION_UP
&& webView.canGoBack()) {
webView.goBack();
return true;
}
return false;
}
});

Actually you can not do directly inside the fragment. The onBackPressed can be overridden in the FragmentActivity. What you can do is:
Override the onBackPressed inside the activity.
When the onBackPressed is called, check if the instance of the current fragment is the instance showing the webview.
If it is, ask the fragment if the webview can go back.
if it is not, call the super or whatever you need
Edit:
#Override
public void onBackPressed() {
Fragment webview = getSupportFragmentManager().findFragmentByTag("webview");
if (webview instanceof MyWebViewFragment) {
boolean goback = ((MyWebViewFragment)webview).canGoBack();
if (!goback)
super.onBackPressed();
}
}

I've created a simple interface:
public interface IOnBackPressed {
boolean onBackPressed();
}
in the Activity:
public class MyActivity extends Activity {
#Override public void onBackPressed() {
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.main_container);
if (!(fragment instanceof IOnBackPressed) || !((IOnBackPressed) fragment).onBackPressed()) {
super.onBackPressed();
}
}
}
in the Fragment:
public class MyFragment extends Fragment implements IOnBackPressed {
#Override
public boolean onBackPressed() {
if (webview.canGoBack()) {
webview.goBack();
// backpress is not considered in the Activity
return true;
} else {
// activity will act normal
return false;
}
}
}

In WebViewActivity.java, I added 1 method:
#Override
public void onBackPressed() {
WebViewFragment fragment = (WebViewFragment)
getSupportFragmentManager().findFragmentById(R.id.fragmentContainer);
if (fragment.canGoBack()) {
fragment.goBack();
} else {
super.onBackPressed();
}
}
In WebViewFragment.java, I added 2 methods:
public boolean canGoBack() {
return mWebView.canGoBack();
}
public void goBack() {
mWebView.goBack();
}

#RomanBlack's answer gave me the right idea, but since we use kotlin I had to adapt the answer a little bit.
webView.setOnKeyListener { _, _, keyEvent ->
if (keyEvent.keyCode == KeyEvent.KEYCODE_BACK && !webView.canGoBack()) {
false
} else if (keyEvent.keyCode == KeyEvent.KEYCODE_BACK && keyEvent.action == MotionEvent.ACTION_UP) {
webView.goBack()
true
} else true
}
if you want to do it with returns you have to add something like:
return#setOnKeyListener true

There is a simple way with BackPressedDispatcher
Fragment:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val callback = object : OnBackPressedCallback(true) {
override fun handleOnBackPressed() {
if(webView.canGoBack()){
webView.goBack()
} else {
isEnabled = false
requireActivity().onBackPressed()
}
}
}
requireActivity().onBackPressedDispatcher.addCallback(this,callback)
}
Activity :
override fun onBackPressed() {
val fragment = supportFragmentManager.findFragmentByTag("WebViewFragment")
if (WebViewFragment::class.java.isInstance(fragment)) {
if (onBackPressedDispatcher.hasEnabledCallbacks()) {
onBackPressedDispatcher.onBackPressed()
return
}
super.onBackPressed()
}
}
Maybe these codes can be improved, but it works very well for me. For more information visit here.

my solution was in fragment I added to public methods
public static boolean canGoBack(){
return mWebView.canGoBack();
}
public static void goBack(){
mWebView.goBack();
}
then from activity I call
#Override
public void onBackPressed() {
if(webFragment.canGoBack()){
webFragment.goBack();
}else{
super.onBackPressed();
}
}
note The mwebview is static

you can do this by :
in the Activity put :
// Set WebView
public void setWebView(WebView web) {
this.web = web;
}
in the web fragment after ActivityCreated() put:
((Your_Activity) getActivity()).setWebView(webView);
Don't forget to set webView from the onCreateView() like these:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
webView = (WebView) inflater.inflate(R.layout.your_web_fragment, container,
false);
return web;
}

#OmidAmnivia answer is correct your app the solution to the crash is
#Override
public void onBackPressed() {
if(webFragment.isInitialized && webFragment.canGoBack()){
webFragment.goBack();
}else{
super.onBackPressed();
}
}
You have to check whether your class has been initialised or not.

This is how I did in my app. I consume back press event till web view can go back. Once web view cant go back I show hint to user that if he keep on pressing back then app will exit.
It will give user a chance to stay in your app when webview cant go back. I felt it more user friendly:
//time passed between two back presses.
private val TIME_INTERVAL = 200
// variable to keep track of last back press
private var mBackPressed: Long = 0
webView!!.requestFocus()
webView.setOnKeyListener(View.OnKeyListener { v, keyCode, event ->
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.action == MotionEvent.ACTION_UP
) {
if(webView.canGoBack()) {
//go back in previous page
webView.goBack()
return#OnKeyListener true
}
else
{
if (mBackPressed + TIME_INTERVAL > System.currentTimeMillis())
{ // dont consume back press and pass to super
return#OnKeyListener false
}
else {
// show hint for double back press
Toast.makeText(context, " Double Tap back button to exit the demo", Toast.LENGTH_SHORT).show();
mBackPressed = System.currentTimeMillis();
return#OnKeyListener true
}
}
}
return#OnKeyListener false
})

First of all get back pressed in fragment
mContentView.setFocusableInTouchMode(true);
mContentView.requestFocus();
mContentView.setOnKeyListener( new OnKeyListener()
{
#Override
public boolean onKey( View v, int keyCode, KeyEvent event )
{
if( keyCode == KeyEvent.KEYCODE_BACK && mWebView.canGoBack())
{
mWebView.goBack();
return true;
}
return false;
}
} );
hope it will works.

This worked in my case
public class FantasyFragment extends Fragment implements SwipeRefreshLayout.OnRefreshListener {
WebView webview;
SwipeRefreshLayout swipeLayout;
String currentUrl="https://www.stackoverflow.com/";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View root = inflater.inflate(R.layout.fragment_stadium, container, false);
swipeLayout = (SwipeRefreshLayout) root.findViewById(R.id.swipescreen);
swipeLayout.setOnRefreshListener(this);
return root;
}
#Override
public void onStart() {
super.onStart();
LoadWeb();
}
public void LoadWeb() {
webview = (WebView) getActivity().findViewById(R.id.webview786);
swipeLayout.setRefreshing(true);
webview.getSettings().setRenderPriority(WebSettings.RenderPriority.HIGH);
webview.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
webview.getSettings().setAppCacheEnabled(true);
WebSettings webSettings = webview.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setDatabaseEnabled(true);
webSettings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
webSettings.setUseWideViewPort(true);
webSettings.setSavePassword(true);
webSettings.setSaveFormData(true);
webSettings.setEnableSmoothTransition(true);
webview.loadUrl(currentUrl);
webview.setWebViewClient(new WebViewClient() {
#Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Snackbar.make(view, "Connection Error", Snackbar.LENGTH_LONG)
.setAction("Retry", new View.OnClickListener() {
#Override
public void onClick(View v) {
LoadWeb();
}
}).show();
}
#Override
public void onPageFinished(WebView view, String url) {
swipeLayout.setRefreshing(false);
currentUrl = url;
super.onPageFinished(view, url);
}
});
webview.canGoBack();
webview.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.getAction() == MotionEvent.ACTION_UP
&& webview.canGoBack()) {
webview.goBack();
return true;
}
return false;
}
});
}
#Override
public void onRefresh() {
LoadWeb();
}
}

The simplest answer is jut to setOnKeyListeneron into webView itself:
webView.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey( View v, int keyCode, KeyEvent event ) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
if( keyCode == KeyEvent.KEYCODE_BACK && webView.canGoBack()){
webView.goBack();
return true;
}
}
return false;
}
});

Android Fragment handle back button press [duplicate]

This question already has answers here:
How to implement onBackPressed() in Fragments?
(58 answers)
Closed 6 years ago.
I have some fragments in my activity
[1], [2], [3], [4], [5], [6]
And on Back Button Press I must to return from [2] to [1] if current active fragment is [2], or do nothing otherwise.
What is the best practise to do that?
EDIT: Application must not return to [2] from [3]...[6]

When you are transitioning between Fragments, call addToBackStack() as part of your FragmentTransaction:
FragmentTransaction tx = fragmentManager.beginTransation();
tx.replace( R.id.fragment, new MyFragment() ).addToBackStack( "tag" ).commit();
If you require more detailed control (i.e. when some Fragments are visible, you want to suppress the back key) you can set an OnKeyListener on the parent view of your fragment:
//You need to add the following line for this solution to work; thanks skayred
fragment.getView().setFocusableInTouchMode(true);
fragment.getView().requestFocus();
fragment.getView().setOnKeyListener( new OnKeyListener()
{
#Override
public boolean onKey( View v, int keyCode, KeyEvent event )
{
if( keyCode == KeyEvent.KEYCODE_BACK )
{
return true;
}
return false;
}
} );

I'd rather do something like this:
private final static String TAG_FRAGMENT = "TAG_FRAGMENT";
private void showFragment() {
final Myfragment fragment = new MyFragment();
final FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment, fragment, TAG_FRAGMENT);
transaction.addToBackStack(null);
transaction.commit();
}
#Override
public void onBackPressed() {
final Myfragment fragment = (Myfragment) getSupportFragmentManager().findFragmentByTag(TAG_FRAGMENT);
if (fragment.allowBackPressed()) { // and then you define a method allowBackPressed with the logic to allow back pressed or not
super.onBackPressed();
}
}

if you overide the onKey method for the fragment view you're gonna need :
view.setFocusableInTouchMode(true);
view.requestFocus();
view.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
Log.i(tag, "keyCode: " + keyCode);
if( keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_UP) {
Log.i(tag, "onKey Back listener is working!!!");
getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
return true;
}
return false;
}
});

Use addToBackStack method when replacing one fragment by another:
getFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).addToBackStack("my_fragment").commit();
Then in your activity, use the following code to go back from a fragment to another (the previous one).
#Override
public void onBackPressed() {
if (getParentFragmentManager().getBackStackEntryCount() > 0) {
getParentFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}

If you want to handle hardware Back key event than you have to do following code in your onActivityCreated() method of Fragment.
You also need to check Action_Down or Action_UP event. If you will not check then onKey() Method will call 2 times.
Also, If your rootview(getView()) will not contain focus then it will not work. If you have clicked on any control then again you need to give focus to rootview using getView().requestFocus(); After this only onKeydown() will call.
getView().setFocusableInTouchMode(true);
getView().requestFocus();
getView().setOnKeyListener(new OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
Toast.makeText(getActivity(), "Back Pressed", Toast.LENGTH_SHORT).show();
return true;
}
}
return false;
}
});
Working very well for me.

Create interfaces:
BackButtonHandlerInterface
public interface BackButtonHandlerInterface {
void addBackClickListener (OnBackClickListener onBackClickListener);
void removeBackClickListener (OnBackClickListener onBackClickListener);
}
OnBackClickListener
public interface OnBackClickListener {
boolean onBackClick();
}
In Activity:
public class MainActivity extends AppCompatActivity implements BackButtonHandlerInterface {
private ArrayList<WeakReference<OnBackClickListener>> backClickListenersList = new ArrayList<>();
#Override
public void addBackClickListener(OnBackClickListener onBackClickListener) {
backClickListenersList.add(new WeakReference<>(onBackClickListener));
}
#Override
public void removeBackClickListener(OnBackClickListener onBackClickListener) {
for (Iterator<WeakReference<OnBackClickListener>> iterator = backClickListenersList.iterator();
iterator.hasNext();){
WeakReference<OnBackClickListener> weakRef = iterator.next();
if (weakRef.get() == onBackClickListener){
iterator.remove();
}
}
}
#Override
public void onBackPressed() {
if(!fragmentsBackKeyIntercept()){
super.onBackPressed();
}
}
private boolean fragmentsBackKeyIntercept() {
boolean isIntercept = false;
for (WeakReference<OnBackClickListener> weakRef : backClickListenersList) {
OnBackClickListener onBackClickListener = weakRef.get();
if (onBackClickListener != null) {
boolean isFragmIntercept = onBackClickListener.onBackClick();
if (!isIntercept) isIntercept = isFragmIntercept;
}
}
return isIntercept;
}
}
In Fragment:
public class MyFragment extends Fragment implements OnBackClickListener{
private BackButtonHandlerInterface backButtonHandler;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
backButtonHandler = (BackButtonHandlerInterface) activity;
backButtonHandler.addBackClickListener(this);
}
#Override
public void onDetach() {
super.onDetach();
backButtonHandler.removeBackClickListener(this);
backButtonHandler = null;
}
#Override
public boolean onBackClick() {
//This method handle onBackPressed()! return true or false
return false;
}
}
Update
Provide custom back navigation
class MyFragment : Fragment() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// This callback will only be called when MyFragment is at least Started.
val callback = requireActivity().onBackPressedDispatcher.addCallback(this) {
// Handle the back button event
}
// The callback can be enabled or disabled here or in the lambda
}
}

The most ideal way of doing this is found here:
Fragment: which callback invoked when press back button & customize it
public class MyActivity extends Activity
{
//...
//Defined in Activity class, so override
#Override
public void onBackPressed()
{
super.onBackPressed();
myFragment.onBackPressed();
}
}
public class MyFragment extends Fragment
{
//Your created method
public static void onBackPressed()
{
//Pop Fragments off backstack and do your other checks
}
}

#Override
public void onResume() {
super.onResume();
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){
if (mDrawerLayout.isDrawerOpen(GravityCompat.START)){
mDrawerLayout.closeDrawer(GravityCompat.START);
}
return true;
}
return false;
}
});
}

After looking at all solutions, I realised there is a much simpler solution.
In your activity's onBackPressed() that is hosting all your fragments, find the fragment that you want to prevent back press. Then if found, just return. Then popBackStack will never happen for this fragment.
#Override
public void onBackPressed() {
Fragment1 fragment1 = (Fragment1) getFragmentManager().findFragmentByTag(“Fragment1”);
if (fragment1 != null)
return;
if (getFragmentManager().getBackStackEntryCount() > 0){
getFragmentManager().popBackStack();
}
}

We created tiny library for handling back press across multiple fragments and/or in Activity. Usage is as simple as adding dependency in your gradle file:
compile 'net.skoumal.fragmentback:fragment-back:0.1.0'
Let your fragment implement BackFragment interface:
public abstract class MyFragment extends Fragment implements BackFragment {
public boolean onBackPressed() {
// -- your code --
// return true if you want to consume back-pressed event
return false;
}
public int getBackPriority() {
return NORMAL_BACK_PRIORITY;
}
}
Notify your fragments about back presses:
public class MainActivity extends AppCompatActivity {
#Override
public void onBackPressed() {
// first ask your fragments to handle back-pressed event
if(!BackFragmentHelper.fireOnBackPressedEvent(this)) {
// lets do the default back action if fragments don't consume it
super.onBackPressed();
}
}
}
For more details and other use-cases visit GitHub page:
https://github.com/skoumalcz/fragment-back

Or you could use getSupportFragmentManager().getBackStackEntryCount() to check what to do:
#Override
public void onBackPressed() {
logger.d("###### back stack entry count : " + getSupportFragmentManager().getBackStackEntryCount());
if (getSupportFragmentManager().getBackStackEntryCount() != 0) {
// only show dialog while there's back stack entry
dialog.show(getSupportFragmentManager(), "ConfirmDialogFragment");
} else if (getSupportFragmentManager().getBackStackEntryCount() == 0) {
// or just go back to main activity
super.onBackPressed();
}
}

If you manage the flow of adding to back stack every transaction, then you can do something like this in order to show the previous fragment when the user presses back button (you could map the home button too).
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0)
getFragmentManager().popBackStack();
else
super.onBackPressed();
}

For Those Who Use Static Fragment
In a case if you have a static fragment then It would be preferable.
Make an instance object of your fragment
private static MyFragment instance=null;
in onCreate() of MyFragment initialize that instance
instance=this;
also make a function to get Instance
public static MyFragment getInstance(){
return instance;
}
also make functions
public boolean allowBackPressed(){
if(allowBack==true){
return true;
}
return false;
}
//allowBack is a boolean variable that will be set to true at the action
//where you want that your backButton should not close activity. In my case I open
//Navigation Drawer then I set it to true. so when I press backbutton my
//drawer should be get closed
public void performSomeAction(){
//.. Your code
///Here I have closed my drawer
}
In Your Activity You can do
#Override
public void onBackPressed() {
if (MyFragment.getInstance().allowBackPressed()) {
MyFragment.getInstance().performSomeAction();
}
else{
super.onBackPressed();
}
}

Working Code:
package com.example.keralapolice;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentManager.OnBackStackChangedListener;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
public class ChiefFragment extends Fragment {
View view;
// public OnBackPressedListener onBackPressedListener;
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle args) {
view = inflater.inflate(R.layout.activity_chief, container, false);
getActivity().getActionBar().hide();
view.setFocusableInTouchMode(true);
view.requestFocus();
view.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
Log.i(getTag(), "keyCode: " + keyCode);
if (keyCode == KeyEvent.KEYCODE_BACK) {
getActivity().getActionBar().show();
Log.i(getTag(), "onKey Back listener is working!!!");
getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
// String cameback="CameBack";
Intent i = new Intent(getActivity(), home.class);
// i.putExtra("Comingback", cameback);
startActivity(i);
return true;
} else {
return false;
}
}
});
return view;
}
}

I think the easiest way is to create an interface, and in the Activity check if the fragment is of the interface type, and if so, call its method to handle the pop. Here's the interface to implement in the fragment.
public interface BackPressedFragment {
// Note for this to work, name AND tag must be set anytime the fragment is added to back stack, e.g.
// getActivity().getSupportFragmentManager().beginTransaction()
// .replace(R.id.fragment_container, MyFragment.newInstance(), "MY_FRAG_TAG")
// .addToBackStack("MY_FRAG_TAG")
// .commit();
// This is really an override. Should call popBackStack itself.
void onPopBackStack();
}
Here's how to implement it.
public class MyFragment extends Fragment implements BackPressedFragment
#Override
public void onPopBackStack() {
/* Your code goes here, do anything you want. */
getActivity().getSupportFragmentManager().popBackStack();
}
And in your Activity, when you handle the pop (likely in both onBackPressed and onOptionsItemSelected), pop the backstack using this method:
public void popBackStack() {
FragmentManager fm = getSupportFragmentManager();
// Call current fragment's onPopBackStack if it has one.
String fragmentTag = fm.getBackStackEntryAt(fm.getBackStackEntryCount() - 1).getName();
Fragment currentFragment = getSupportFragmentManager().findFragmentByTag(fragmentTag);
if (currentFragment instanceof BackPressedFragment)
((BackPressedFragment)currentFragment).onPopBackStack();
else
fm.popBackStack();
}

I'm working with SlidingMenu and Fragment, present my case here and hope helps somebody.
Logic when [Back] key pressed :
When SlidingMenu shows, close it, no more things to do.
Or when 2nd(or more) Fragment showing, slide back to previous Fragment, and no more things to do.
SlidingMenu not shows, current Fragment is #0, do the original [Back] key does.
public class Main extends SherlockFragmentActivity
{
private SlidingMenu menu=null;
Constants.VP=new ViewPager(this);
//Some stuff...
#Override
public void onBackPressed()
{
if(menu.isMenuShowing())
{
menu.showContent(true); //Close SlidingMenu when menu showing
return;
}
else
{
int page=Constants.VP.getCurrentItem();
if(page>0)
{
Constants.VP.setCurrentItem(page-1, true); //Show previous fragment until Fragment#0
return;
}
else
{super.onBackPressed();} //If SlidingMenu is not showing and current Fragment is #0, do the original [Back] key does. In my case is exit from APP
}
}
}

This is a very good and reliable solution: http://vinsol.com/blog/2014/10/01/handling-back-button-press-inside-fragments/
The guy has made an abstract fragment that handles the backPress behaviour and is switching between the active fragments using the strategy pattern.
For some of you there maybe a little drawback in the abstract class...
Shortly, the solution from the link goes like this:
// Abstract Fragment handling the back presses
public abstract class BackHandledFragment extends Fragment {
protected BackHandlerInterface backHandlerInterface;
public abstract String getTagText();
public abstract boolean onBackPressed();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(!(getActivity() instanceof BackHandlerInterface)) {
throw new ClassCastException("Hosting activity must implement BackHandlerInterface");
} else {
backHandlerInterface = (BackHandlerInterface) getActivity();
}
}
#Override
public void onStart() {
super.onStart();
// Mark this fragment as the selected Fragment.
backHandlerInterface.setSelectedFragment(this);
}
public interface BackHandlerInterface {
public void setSelectedFragment(BackHandledFragment backHandledFragment);
}
}
And usage in the activity:
// BASIC ACTIVITY CODE THAT LETS ITS FRAGMENT UTILIZE onBackPress EVENTS
// IN AN ADAPTIVE AND ORGANIZED PATTERN USING BackHandledFragment
public class TheActivity extends FragmentActivity implements BackHandlerInterface {
private BackHandledFragment selectedFragment;
#Override
public void onBackPressed() {
if(selectedFragment == null || !selectedFragment.onBackPressed()) {
// Selected fragment did not consume the back press event.
super.onBackPressed();
}
}
#Override
public void setSelectedFragment(BackHandledFragment selectedFragment) {
this.selectedFragment = selectedFragment;
}
}

rootView.setFocusableInTouchMode(true);
rootView.requestFocus();
rootView.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
Fragment NameofFragment = new NameofFragment;
FragmentTransaction transaction=getFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container,NameofFragment);
transaction.commit();
return true;
}
return false;
}
});
return rootView;

Add addToBackStack() to fragment transaction and then use below code for Implementing Back Navigation for Fragments
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// Update your UI here.
}
});

if you are using FragmentActivity. then do like this
first call This inside your Fragment.
public void callParentMethod(){
getActivity().onBackPressed();
}
and then Call onBackPressed method in side your parent FragmentActivity class.
#Override
public void onBackPressed() {
//super.onBackPressed();
//create a dialog to ask yes no question whether or not the user wants to exit
...
}

You can use from getActionBar().setDisplayHomeAsUpEnabled() :
#Override
public void onBackStackChanged() {
int backStackEntryCount = getFragmentManager().getBackStackEntryCount();
if(backStackEntryCount > 0){
getActionBar().setDisplayHomeAsUpEnabled(true);
}else{
getActionBar().setDisplayHomeAsUpEnabled(false);
}
}

Add this code in your Activity
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() == 0) {
super.onBackPressed();
} else {
getFragmentManager().popBackStack();
}
}
And add this line in your Fragment before commit()
ft.addToBackStack("Any name");

in fragment class put this code for back event:
rootView.setFocusableInTouchMode(true);
rootView.requestFocus();
rootView.setOnKeyListener( new OnKeyListener()
{
#Override
public boolean onKey( View v, int keyCode, KeyEvent event )
{
if( keyCode == KeyEvent.KEYCODE_BACK )
{
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, new Book_service_provider()).commit();
return true;
}
return false;
}
} );

Checking the backstack works perfectly
#Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if (keyCode == KeyEvent.KEYCODE_BACK)
{
if (getFragmentManager().getBackStackEntryCount() == 1)
{
// DO something here since there is only one fragment left
// Popping a dialog asking to quit the application
return false;
}
}
return super.onKeyDown(keyCode, event);
}

In your oncreateView() method you need to write this code and in KEYCODE_BACk condition you can write whatever the functionality you want
View v = inflater.inflate(R.layout.xyz, container, false);
//Back pressed Logic for fragment
v.setFocusableInTouchMode(true);
v.requestFocus();
v.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
getActivity().finish();
Intent intent = new Intent(getActivity(), MainActivity.class);
startActivity(intent);
return true;
}
}
return false;
}
});

How to go back to previous page if back button is pressed in WebView?

I have an app in which I have a WebView where I display some websites. It works, clicking a link in the webpage goes to the next page in the website inside my app. But when I click the phone's back button, it takes me straight into my app. I want to go back to the previous page in the website instead. How can I do this?
Here is the code sample I'm using:
public class Webdisplay extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
setContentView(R.layout.webdisplay);
getWindow().setFeatureInt(Window.FEATURE_PROGRESS,
Window.PROGRESS_VISIBILITY_ON);
Toast loadingmess = Toast.makeText(this,
"Cargando El Diario de Hoy", Toast.LENGTH_SHORT);
loadingmess.show();
WebView myWebView;
myWebView = (WebView) findViewById(R.id.webview);
myWebView.getSettings().setJavaScriptEnabled(true);
myWebView.loadUrl("http://www.elsalvador.com");
myWebView.setWebViewClient(new WebViewClient());
myWebView.setInitialScale(1);
myWebView.getSettings().setBuiltInZoomControls(true);
myWebView.getSettings().setUseWideViewPort(true);
final Activity MyActivity = this;
myWebView.setWebChromeClient(new WebChromeClient()
{
public void onProgressChanged(WebView view, int progress)
{
MyActivity.setTitle("Loading...");
MyActivity.setProgress(progress * 100);
if(progress == 100)
MyActivity.setTitle(R.string.app_name);
}
});
}
}

I use something like this in my activities with WebViews:
#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);
}
Edit:
For this code to work, you need to add a field to the Activity containing the WebView:
private WebView mWebView;
Initialize it in the onCreate() method and you should be good to go.
mWebView = (WebView) findViewById(R.id.webView);

If using Android 2.2 and above (which is most devices now), the following code will get you what you want.
#Override
public void onBackPressed() {
if (webView.canGoBack()) {
webView.goBack();
} else {
super.onBackPressed();
}
}

This is my solution. It works also in Fragment.
webView.setOnKeyListener(new 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;
}
});

Full reference for next button and progress bar : put back and next button in webview
If you want to go to back page when click on phone's back button, use this:
#Override
public void onBackPressed() {
if (webView.canGoBack()) {
webView.goBack();
} else {
super.onBackPressed();
}
}
You can also create custom back button like this:
btnback.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (wv.canGoBack()) {
wv.goBack();
}
}
});

Focusing should also be checked in onBackPressed
#Override
public void onBackPressed() {
if (mWebview.isFocused() && mWebview.canGoBack()) {
mWebview.goBack();
} else {
super.onBackPressed();
finish();
}
}

Why not use onBackPressed()?
#Override
public void onBackPressed() {
// super.onBackPressed(); Do not call me!
// Go to the previous web page.
}

here is a code with confirm exit:
#Override
public void onBackPressed()
{
if(webView.canGoBack()){
webView.goBack();
}else{
new AlertDialog.Builder(this)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Exit!")
.setMessage("Are you sure you want to close?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
})
.setNegativeButton("No", null)
.show();
}
}

In kotlin:
override fun onBackPressed() {
when {
webView.canGoBack() -> webView.goBack()
else -> super.onBackPressed()
}
}
webView - id of the webview component in xml, if using synthetic reference.

#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
// Check if the key event was the Back button and if there's history
if ((keyCode == KeyEvent.KEYCODE_BACK) && myWebView.canGoBack()) {
myWebView.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);
}

WebView mWebView;
mWebView = findViewById(R.id.webView);
#Override
public void onBackPressed() {
if (webView.canGoBack()) {
webView.goBack();
} else {
super.onBackPressed();
}
}

The first answer by FoamyGuy is correct but I have some additions; low reputations cannot allow me to do comments. If for some reasons your page fails to load, ensure that you set a flag to take note of the failure and then check it on the onBackPressed override. Otherwise your canGoBack() will be forever executed without heading to the actual back activity if it was there:
//flag with class wide access
public boolean ploadFailFlag = false;
//your error handling override
#Override
public void onReceivedError(WebView view, WebResourceRequest req, WebResourceError rerr) {
onReceivedError(view, rerr.getErrorCode(), rerr.getDescription().toString(), req.getUrl().toString());
ploadFailFlag = true; //note this change
.....
.....
}
//finally to the answer to this question:
#Override
public void onBackPressed() {
if(checkinWebView.canGoBack()){
//if page load fails, go back for web view will not go back - no page to go to - yet overriding the super
if(ploadFailFlag){
super.onBackPressed();
}else {
checkinWebView.goBack();
}
}else {
Toast.makeText(getBaseContext(), "super:", Toast.LENGTH_LONG).show();
super.onBackPressed();
}
}

You can try this for webview in a fragment:
private lateinit var webView: WebView
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val root = inflater.inflate(R.layout.fragment_name, container, false)
webView = root!!.findViewById(R.id.home_web_view)
var url: String = "http://yoururl.com"
webView.settings.javaScriptEnabled = true
webView.webViewClient = WebViewClient()
webView.loadUrl(url)
webView.canGoBack()
webView.setOnKeyListener{ v, keyCode, event ->
if(keyCode == KeyEvent.KEYCODE_BACK && event.action == MotionEvent.ACTION_UP
&& webView.canGoBack()){
webView.goBack()
return#setOnKeyListener true
}
false
}
return root
}

You should the following libraries on your class handle the onBackKeyPressed.
canGoBack() checks whether the webview can reference to the previous page. If it is possible then use the goBack() function to reference the previous page (go back).
#Override
public void onBackPressed() {
if( mWebview.canGoBack()){
mWebview.goBack();
}else{
//Do something else. like trigger pop up. Add rate app or see more app
}
}

Here is the Kotlin solution:
override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
if (event?.action != ACTION_UP || event.keyCode != KEYCODE_BACK) {
return super.onKeyUp(keyCode, event)
}
if (mWebView.canGoBack()) {
mWebView.goBack()
} else {
finish()
}
return true
}

If someone wants to handle backPressed for a webView inside a fragment, then he can use below code.
Copy below code into your Activity class (that contains a fragment YourFragmmentName)
#Override
public void onBackPressed() {
List<Fragment> fragmentList = getSupportFragmentManager().getFragments();
boolean handled = false;
for(Object f: fragmentList) {
if(f instanceof YourFragmentName) {
handled = ((YourFragmentName)f).onBackPressed();
if(handled) {
break;
}
}
}
if(!handled) {
super.onBackPressed();
}
}
Copy this code in the fragment YourFragmentName
public boolean onBackPressed() {
if (webView.canGoBack()) {
webView.goBack();
return true;
} else {
return false;
}
}
Notes
Activity should be replaced with the actual Acitivity class you are using.
YourFragmentName should be replaced with the name of your Fragment.
Declare webView in YourFragmentName so that it can be accessed from within the function.

I think I'm a little late but according to the android documentation, you can have custom back navigation inside fragments done by the following piece of code.
requireActivity().onBackPressedDispatcher.addCallback(this) {
// Handle the back button event
if (binding.webView.canGoBack()){
binding.webView.goBack()
} else {
findNavController().popBackStack()
}
}
you can customize what to do when you the webView cant go back as per your needs.

Official Kotlin Way:
override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
// Check if the key event was the Back button and if there's history
if (keyCode == KeyEvent.KEYCODE_BACK && myWebView.canGoBack()) {
myWebView.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)
}
https://developer.android.com/guide/webapps/webview.html#NavigatingHistory

use this code to go back on page and when last page came then go out of activity
#Override
public void onBackPressed() {
super.onBackPressed();
Intent intent=new Intent(LiveImage.this,DashBoard.class);
startActivity(intent);
}

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.

How to control navigation history in webview inside fragment - android

You can try it #Override public void onBackPressed() { if (mWebView.canGoBack()) { mWebView.goBack(); return; } // Otherwise defer to system default behavior. super.onBackPressed(); }

Related

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How to add "Go Back" function in WebView inside Fragment?

Android Fragment handle back button press [duplicate]

How to go back to previous page if back button is pressed in WebView?

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