I'm junior of android developer. (super beginner T_T)
I'm having trouble with Android Webview.
I am making a Hybrid app.
- when touch the app icon, it is linked to the webview(webview.loadurl(url)) directly.
When I click the home button after loading url and searching the web page (which is loaded through the webview),
and then re-click the app icon or touch the webview processing through click the home button long~.
I want to keep the page I've seen right before click the home button.
but It doesn't work.
Just reload the main index page.
I want...
Index page(login.jsp) -> A page -> B page -> Home button -> re-click the app or ~ -> B page
but unfourtunately, it works
Index page(login.jsp) -> A page -> B page -> Home button -> re-click the app or ~ -> Index page -> back key -> B page... It really strange.. \T_T
(back key -> B page :: Session didnt fired. may be keeped.)
I searched a lot about these problems.
Many people answered - Using Cookies and keep the session. but it also didn't work for me.
I know I didnt explain current problem well and show the code to you.
but I really really need help .
So please give me any hint.
Do I have to save the url adress which I searched last.?
Just to make sure we're talking about the same thing: when you say "home button," you mean the Android home button, not something on the web page, right?
When you press the home button, your activity is stopped; and it is restarted when the user returns to your app. The activity does not necessarily get destroyed and recreated, but it could, in which case the state is lost (except for state that the activity automatically saves).
I don't know about webview specifically, but if your activity is losing important state, such as the URL of the B page, you can save and restore it by overriding onSaveInstanceState() and onRestoreInstanceState().
Related
I've got an xamarin forms/prism app, and my hardware back button does nothing on the initial page.
If I navigate to another page, it closes the app as expected. If I navigate to the initial page again, it also closes the app - but not if the app just started.
Is there something I'm missing?
My class App mainly has an OnInitialized that navigates to the initial page:
protected override void OnInitialized()
{
NavigationService.NavigateAsync( "MyMasterDetail/MyNavigationPage/StartPage", animated: false );
}
On MyMasterDetail, there are buttons that navigate to MyNavigationPage/SettingsPage and other pages like that.
It doesn't matter if I use Android 5 in Emulator or Android 6 on a real device, the behaviour is the same.
When using a MasterDetail as your root, you are not actually navigating anywhere else. You are simply changing the Detail property of the MasterDetail to another Page. This is not a navigation action. So you are not really navigating. If you want to fake it, you need to add the INavigationPageOptions to your MyNavigationPage and set the ClearNavigationStackOnNavigation property to false. This will continuously push new pages onto the MasterDetailPage.Detail MyNavigationPage without clearing the stack (PopToRoot). Then this will allow your bac button to behave like you are wanting.
I have built a Meteor app with a mobile app interface (using Ratchet), only designed to be run as an app. On each page, there is a "back" link that takes you back to the parent page. For example, if I go deep inside a hierarchy of page such as this one:
Home > Category > Post
I can use a link in the Post page that will take me back to the Category page. Now, the problem is, if from this Category page I hit the back button, it should have the same behaviour as clicking the back link on the page. (in this case, take me to the Home page) Sadly, this doesn't happen and I get taken back to the Post page.
On iPhone it is not a problem (as far as I know) since there is no actual back button built-in to the device. But on Android it gives me headaches, for example:
Say a user goes to a Post page that he can delete using a button shown on the page. When the post-deletion method finishes, I take the user back to the Category page:
Router.go('categoryPage', {'_id': categoryId});
Problem is: if the user hits the back button after deleting a post, he or she gets taken to a "not found" page, since the previous post has been deleted. Now I can avoid that by adding replaceState: true like this:
Router.go('categoryPage', {'_id': categoryId}, {replaceState: true});
But now when the user hits the back button from the Category page, he or she gets taken to the page that was there before the Post page, which was... the same Category page. So the button just does nothing on the first press.
I also tried to pushState the url of the desired page in each of my template's `rendered̀€ function, to no avail (and what would I put in there for the Home page?):
Template.categoryPage.rendered = function () {
history.pushState(null, null, Router.url('home'));
};
Template.postPage.rendered = function () {
history.pushState(null, null, Router.url('categoryPage', {'_id': this.data.categoryId}));
};
Has anyone tackled this issue and/or would be able to drop some knowledge?
As soon as the back button is pressed, Cordova trigger a "backbutton" event, see there.
By listening to this event you should be able to override the default behavior and do what you want:
document.addEventListener("backbutton", onBackButtonDown, false);
function onBackButtonDown(event) {
event.preventDefault();
event.stopPropagation();
// Do what you want
...
}
I am having a specific problem in my android app. I have 2 activities and the flow is from
Activity 1 to Activity 2.
I press back button from Activity 2 and then it goes to activity 1. This is great. But in some devices if I stay too long on activity 2(Like for days, I check it once in a while ) , and when I press back button it doesn't go back. So I guess history is cleared by android os for getting more memory.
I know that I can manually override onBackPressed() and achieve the functionality, but I need a perfect solution for this. so it will be like
If the history is all right let android handle back, If history is disturbed then I should be able to handle it.
IS there any way to check any issue with history?
I'm ware of androids life cycle and that it's not needed to add a "exit" button in the application.
But still, this back button stuff isn't really working out well.
You maybe know this issue from the default SMS-App that android comes with: you open it when you get a new message and exit it using the menu button or something else.
After like 20 times doing this, you then decide to exit the app using the back button, what happens? you have to go back though 20 views. every time you press back you return to the "all messages (by sender)" listview and when you press back there again you return to the message opend 20-1 (message 19). again you press back and return to the listview and again you press back and end up at message 18. till, after40 times pressing back, you finally exit the messanger app.
same happens when for example you got a action bar with a "home" icon which opens the main screen of your app. the user picks a action and the new activity starts. than the user clicks the home button and returns to the main screen. when pressing the back button - no matter if you call finish() in the onButtonBack listener or not, you the user would expect the app to exit, but in fact the app returns to the previous activity which is wrong.
such cycleing may happen for various reasons, thats why - even thought i'm aware of the supposed to be lifecycle of android - i wan't to EXIT (& destroy) the app when pressing back within a defined activity.
calling finish() dosn't help. if there's a previous activity it will re-open it. calling system.exit(0) isn't nice to do.
so: whats the right way to prevent such back-press-cycles and/or exit a application (WITH destruction)?
for better illustration of what i want to achieve: consider A, B, C being activities. a arrow (-->) illustrations a new intent call from the activity leftside of the arrow, rightside of the arrow represents the activity that is called. ex.: A --> B means activity A starts activity B. now here's what i want:
1) A --> B --> C pressBack:--> B pressBack:-->A pressBack:--> Exit
2) A --> B pressBack: --> A pressBack: --> Exit
3) A --> B --> A pressBack:--> Exit
as you see, back works as always, BUT when in activity A it exits the application.
the behaviour i got now is 1) and 2) as above but
3) A --> B --> A pressBack:--> A pressBack: --> Exit
keep in mind, i've already overwritten the onBackPressed listener of activity A with a finish() call. even calling system.exit(0) dosnt work. however, even if it would: its not what i want, i want the REAL way to do it android style - i cant imagine system.exit(0) is best practise.
Well this is the default behavior.
If you have another approach, just implement it.
One approach to deal with this is to use the android:launchMode="singleInstance" for activities that can be launched in a singleton manner (only one activity can exist)
For example, if the SMS page in the SMS app was a singleTop, it would have needed only one back press to remove all the SMS pages. It is a matter of choice
Another more aggressive way would be to finish Activities when you start another activity. Of course, such decision would risk making the app less friendly (android users are not accustomed to this behavior). Nevertheless, if this is used only where it may be considered acceptable then it might be acceptable.
A very acceptable place to do this would be a login screen: Once login is successfull, you start another activity (probably designed for logged in users) and finish the login activity.
Enjoy Finally, in my personal opinion, you can add an Exit button. Users will find it nice.
Check my post: Adding an Exit button to Android Application
I am still learning the ins and outs of Android development. I am playing around with the Notepad tutorial application to try and get different behavior.
Right now, I want to have the application do the following in the NoteEdit activity:
1) If the Back button is pressed, current state is ignored; basically, it's like an implicit cancel, and you are taken back to the list.
2) If the Home button is pressed, it takes you to the home page as normal. However, if you open the application again, it should go back into the NoteEdit activity in the same state as when you left (IE, if you were partway through an edit, for example).
I removed the "saveState" stuff from onPause, because I don't want to store to the DB unless "Confirm" is pressed (instead, I moved the call to saveState to the confirm button). By doing this, hitting "Back" basically throws out your changes, which is what I want. However, going Home and coming back also throws out your changes, though it does remain in the NoteEdit activity. Both "Back" and "Home" cause the onPause message to trigger, and both cause onResume to trigger (either from clicking on the item in the "Back" case, or by going back into the app in the "Home" case).
Is there a way to have these two events handle saving the state differently? Is it possible to have the Home button store the state (temporarily), while not having the Back button do it?
Thanks in advance!
You need to define an onSaveInstanceState method, but instead of saving to the DB (as in the Notepad sample), save your Activity's state to the Bundle. You then need to recover from the saved state in your onCreate when the passed in Bundle is non-null.