I am playing with an ap that has 2 webviews set up within a tabhost/tabwidget layout, my problem is that i don't know how to make them navigate back through page history, at least for both of them. I ca do it for the first webview (webview1) but i don't know how to do it for the second one in my second tab.
I know this question is ancient but you might still be stuck on it, or someone else might be. Use the code below, it works for me using tabHost. webView1 and webView2 being your two webviews.
Add it above the onCreate bundle.
public void onBackPressed(){
if (webView1.isFocused() && webView1.canGoBack()) {
webView1.goBack();
}
else {
//Add something you want to do, or leave blank to do nothing.
}
if (webView2.isFocused() && webView2.canGoBack()) {
webView2.goBack();
}
else {
//Add something you want to do, or leave blank to do nothing.
}
}
Related
This question and its answers (copied below) provide a solution for handling the back button in Ionic, but that solution only works when other pages are pushed directly from app.component, in which case calling canGoBack and getActive() on this.nav works correctly because other pages have been pushed using this.nav.push in app.component.
However if a page is pushed from one of the pages in the tabs (lets call it page1), i.e. by calling this.navCtrl.push() in page1, then this.nav.canGoBack() in app.components still resolves to false because the push happened using the page1's this.navCtrl.push() not app.component's this.nav.push().
How can I detect inside app.components if a page was pushed from any of pages in the tabs?
platform.registerBackButtonAction(() => {
if(this.nav.canGoBack()){
this.nav.pop();
}else{
if(this.alert){
this.alert.dismiss();
this.alert =null;
}else{
this.showAlert();
}
}
});
});
}
I'm using AppGyver Steroids and Supersonic to build an app and I'm having some issues navigating between views programmatically.
Based on the docs, you navigate between views like this:
var view_obj = new supersonic.ui.View("main#index");
supersonic.ui.layers.push(view_obj);
However, when I inspect things via the Chrome DevTools, it appears that a second duplicate view is created i.e. If I navigate away from the index page and then navigate back, I now have two index pages, instead of what [I think] should be one. It also doesn't close the previous view I was on.
How can I prevent this from happening and simply move to the existing view, instead of duplicating views? How do I close a view after I have navigated away from it?
Thanks.
The problem you're encountering is that you're creating a new supersonic.ui.View("main#index") every time you navigate. On top of this, I think you want to return to the same view when you navigate back to a view for the second time, i.e. you want the view to remain in memory even if it has been removed from the navigation stack with pop() (rather than pushing a new instance of that view). For this, you need to preload or "start()" the view, as described in the docs here.
I implemented my own helper function to make this easier; here is my code:
start = function(dest, isModal) {
var viewId=dest,
view=new supersonic.ui.View({
location: dest,
id: viewId
});
view.isStarted().then(function(started) {
if (started) {
if (isModal) {supersonic.ui.modal.show(view);}
else {supersonic.ui.layers.push(view);}
} else {
// Start Spinner
supersonic.ui.views.start(view).then(function() {
if (isModal) {supersonic.ui.modal.show(view);}
else {supersonic.ui.layers.push(view);}
// Stop Spinner
}, function(error) {
// Stop Spinner
A.error(error);
});
}
});
};
Use it like start('module#view');. As a bonus, you can pass true as the second argument and it gets pushed as a modal instead.
It checks if you've already started a view - if so, it just pushes that view back onto the stack. If not, it start()s (i.e. preloads) it, then pushes it. This ensures that the view stays in memory (with any user input that has been modified) even when you pop() it from the stack.
You have to imagine that the layer stack is actually a stack in the Computer Science sense. You can only add and remove views at the top of the stack. The consequence of this is that complex navigations such as A > B > C > D > B are difficult/hacky to do (in this case, you'd have to pop() D and C in succession to get back to B).
Views will close if you pop() them, as long as you didn't start() them. If you did, and you pop() them, they remain in memory. To kill that view, you have to call stop() on it, as described in the docs I linked above.
try
var view_obj = new supersonic.ui.View("main#index");
supersonic.ui.layers.replace(view_obj);
And take a look at supersonic.ui.layers.pop();
Thanks to LeedsEbooks for helping me get my head around this challenge. I was able to find a solution. Here is the code:
var start = function(route_str, isModal) {
var regex = /(.*?)#(.*)/g;
var match_obj = regex.exec(route_str);
var view_id_str = match_obj[2],
view_location_str = route_str,
view = new supersonic.ui.View({
location: view_location_str,
id: view_id_str
});
view.isStarted().then(function(started) {
if (started)
{
if (isModal)
{
supersonic.ui.modal.show(view);
}
else {
supersonic.ui.layers.push(view);
}
}
else
{
// Start Spinner
supersonic.ui.views.start(view).then(function() {
if (isModal)
{
supersonic.ui.modal.show(view);
}
else
{
supersonic.ui.layers.push(view);
}
// Stop Spinner
}, function(error) {
// Stop Spinner
A.error(error);
});
}
});
};
You must ensure that your route has the format module#view as defined in the documentation.
PLEASE NOTE
There seems to some problem with the supersonic ui method for starting views. If you run the following code:
supersonic.ui.views.start("myapp#first-view");
supersonic.ui.views.find("first-view").then( function(startedView) {
console.log(startedView);
});
You'll notice that your view id and location are identical. This seems to be wrong as the id should be first-view and location should be myapp#first-view.
So I decided to not use the AppGyver methods and create my own preload method instead, which I run from the controller attached to my home view (this ensures that all the views I want to preload are handled when the app loads). Here is the function to do this:
var preload = function(route_str)
{
var regex = /(.*?)#(.*)/g;
var match_obj = regex.exec(route_str);
var view = new supersonic.ui.View({
location: route_str,
id: match_obj[2]
});
view.start();
};
By doing this, I'm sure that the view will get loaded with the right location and id, and that when I use my start() function later, I won't have any problems.
You'll want to make sure that your structure.coffee file doesn't have any preload instructions so as not to create duplicate views that you'll have problems with later.
Finally, I have a view that is 2 levels in that is a form that posts data via AJAX operation. I wanted the view to go back to the previous view when the AJAX operation was complete. Using my earlier function resulted in the push() being rejected. It would be nice if AppGyver Supersonic could intelligently detect that pushing to a previous view should default to a layers.pop operation, but you don't always get what you want. Anyway, I managed to solve this using supersonic.ui.layers.pop(), which simply does what the Back button would have done.
Everything working as intended now.
EDIT: tl;dr: WebView appears as white box, even though I appear to be setting it up correctly, and indeed it does work the first two times, but fails subsequently)
EDIT: Video showing the problem in action...
I have the following bit of code which inflates a view (Which contains a WebView) from the xml which defines it:
private void createCard(ViewGroup cvFrame, Card card) {
//... setup vairables...
cvFrame.clearDisappearingChildren();
cvFrame.clearAnimation();
try {
View cv = LayoutInflater.from(getBaseContext()).inflate(R.layout.card_back_view,
cvFrame, true);
cv.setBackgroundDrawable(Drawable.createFromStream(mngr.open(deckName + "_Card_back.png"), deckName));
TextView suit = (TextView)cv.findViewWithTag("card_back_suit");
//...setup text view for suit, this code works fine every time...
WebView title = (WebView)cv.findViewWithTag("card_back_title");
//This WebView doesn't appear to be the one which actually appears on screen (I can change settings till I'm blue in the face, with no effect)
if (title != null) {
title.setBackgroundColor(0x00000000);
title.loadData(titleText, "text/html", "UTF-8");
} else {
Log.e("CardView", "Error can't find title WebView");
}
} catch (IOException e) {
Log.e("CardView", "Error making cards: ", e);
}
}
When this method is called as part of the onCreate method in my Activity, the WebView contains the correct code, and is suitably transparent.
I have a gesture listener which replaces the contents of the ViewGroup with different content (It animates the top card off to the left, replaces the contents of the top card with card 2, puts the top card back, then replaces card 2 with card 3)
//Gesture listener event
ViewGroup cvFrame = (ViewGroup)findViewById(R.id.firstCard);
cardLoc++
cvFrame.startAnimation(slideLeft);
(onAnimationEnd code)
public void onAnimationEnd(Animation animation) {
if (animation == slideLeft) {
ViewGroup cvFrameOldFront = (ViewGroup)findViewById(R.id.firstCard);
ViewGroup cvFrameNewFront = (ViewGroup)findViewById(R.id.secondCard);
createCard(cvFrameOldFront, cards.get((cardLoc)%cards.size()));
createCard(cvFrameNewFront, cards.get((cardLoc+1)%cards.size()));
TranslateAnimation slideBack = new TranslateAnimation(0,0,0,0);
slideBack.setDuration(1);
slideBack.setFillAfter(true);
cvFrameOldFront.startAnimation(slideBack);
}
}
When the animation has happened and I replace the contents of the cards, the TextView suit is replaced fine and the code definitely passes through the code to replace the WebView contents, but for some reason I end up with a white rectangle the size and shape of the WebView, no content, no transparency.
If I change the WebView to a TextView, it's contents is replaced fine, so it's an issue that occurs only with the WebView control :S
Can anyone tell me why / suggest a fix?
It turns out the WebView doesn't get cleared down when using the LayoutInflater to replace the contents of a ViewGroup. The other controls all seem to get removed (or at least the findViewWithTag() returns the right reference for every other control). I've just added in the line cvFrame.removeAllViews() immediately before the LayoutInflater does it's stuff and that fixed the issue.
If anyone has any better explanation for this I'll throw the points their way otherwise they will just go into the ether...
By calling findViewById, you are getting a reference on the previously loaded webview do you ?
so the loadData call that fails is the second one you make on a single webview instance.
you may want to check this :
Android WebView - 1st LoadData() works fine, subsequent calls do not update display
It appears that loadData() won't load data twice... you may want to try WebView.loadDataWithBaseUri()
Hope that helps.
I had a similar problem loading several WebViews content.
It was because of a misusing of the pauseTimers function
The situation was : the first webView weren't needed anymore, conscientiously I wanted to pause it before to release it. Calling onPause() and pauseTimers()
pauseTimers being common to any web views, it broke every use of webviews occuring after that, there were displaying only white rectangles.
Maybe its not your problem here, but it's worth checking your not calling WebView.pauseTimers() somewhere.
To confirm your answer, the source code for LayoutInflater.inflate(int resource, ViewGroup root, boolean attachToRoot) does in fact internally calls root.addView() which attaches the newly inflated view at the end of the root's children instead of replacing them.
So the mystery now is why did your call to findViewWithTag() is returning the expected objects for your other widgets (which would be the top, most recently created instances), but for your WebView it was returning something else.
Is it possible that there is another object in your layout XML which shares the same "card_back_title" tag?
I was also wondering why you didn't use the more common findViewById() instead, but I am not sure whether it would make a difference.
I am making an app that has a scrolling screen like the homescreen style. I have implemented this solution:
Android Homescreen
It works great but I also want there to be buttons on each page that you can click to go to the next page but I just can't figure out how to do it! can someone help? I've been staring at this code for days now!
Thanks
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
UPDATE - HELP
I really don't understand how to get around the problem of calling the SetToScreen from the other activity, Can anyone help as if I try I do keep getting Static call errors.
Look at
public void setToScreen(int whichScreen) {}
Use this function to set to a screen on a click.
you should extend Draggablespace by adding a function to get the current space like:
public int getCurrentScreen() {
return this.mCurrentScreen;
}
then you can write your own functions in your activity like
public void nextScreen() {
draggableSpace.setToScreen(draggableSpace.getCurrentScreen() + 1));
}
The same for previous screen.
Now you only need to check if there is an additional screen waiting if you are going forward or backward.
(Of course draggableSpace is your object of the class draggablespace...not a static call!)
I have an android application that loads web pages in an activity with a WebView. I am using the retrieving the page manually and using WebView's loadDataWithBaseURL to display it on screen. Everything there is fine.
Now, i am trying to override the Back button press to simulate going back in the WebView history stack. I am able to override the Back button press, i can see that there is a history stack in the WebView, i can see that the history url is correct, but when i call WebView's goBack() method, it displays a blank page.
Anyone encountered this before or give me a couple of suggestions to proceed from this?
Edit: If i use WebView's loadUrl method, the Back button with an override works as intended. But why.... If i need to handle this manually, how do i start messing with history pages?
I got the same problem also. I found that the problem went away if I set the historyUrl parameter on the call to loadDataWithBaseURL.
You should check if the canGoBack() method returns true before calling goBack()
The only solution I've found is to create a Stack<String> and manually manage history
The way I deal with this is keeping a local stack pointer to the number of loaded pages after the root page loaded using loadDataWithBaseURL . When going back, if my pointer hits 1 I am at root level and reload the root page with loadDataWithBaseURL.
FYI, I use this code in Activities with fragments, so the fragments implement the interface IBackButtonListener which helps me to capture the back button in the main activity and propagate the event to the current fragment. If the fragment returns true it means it has taken care of the event.
IBackbuttonListener.java
public interface IBackButtonListener {
public boolean onBackButtonPressed();
}
Fragment that implements IBackButtonListener and has a webview loaded from html data.
private int historyStackPointer = 0;
...
#Override
public boolean onBackButtonPressed() {
boolean rtn = false;
if (webView.canGoBack()) {
if(historyStackPointer > 1) {
webView.goBack();
historyStackPointer--;
rtn = true;
}else{
if(historyStackPointer == 1) {
// Reload the html data
webView.loadDataWithBaseURL("file:///android_asset/", html_data, "text/html", "UTF-8", null);
historyStackPointer = 0;
rtn = true;
}else{
webView.loadUrl("about:blank");
rtn = false;
}
}
} else {
rtn = false;
}
return rtn;
}
html_data is a String with the page's html.
What I noticed is that if the url ends in .html, that white screen appears when back button is pressed.
On the other hand, if you remove that .html from your url - obviously only if this is supported by that website (i.e. the redirection and all is handled properly at the server side and that it doesn't trigger the 404 Page Not Found error), that url will act as your base this time and when you press the back button, that white screen should not appear this time.
for example: you have to replace
http://example.com/page.html to:
http://example.com/page