We're trying to provide an application to the mentally and physically handicapped daughter of my neighbor that let's her use an Android tablet as a Talker, i.e., she presses a few big buttons and the devices generates speech. The application is basically a WebView and an additional object in Javascript used to perform and control the speech generation, plus some logic to handle the orientation changes. Html files are generated offline for her specific layout of the talking items. We've also added some music playing and picture viewing facilities to make the device more appealing to her.
Problem is that the home button brings her back into the madness of the Android launcher screen, and that on the test device (Archos 70) the home button is not a physical button but rather shown on the touch screen itself, making it too easy to accidentally hit it.
So I'd like to return to the Android launcher only by pressing a sequence home, back, home with no other action in between.
Can I achieve this by making my application itself the launcher? How can I then get back to the original launcher upon the home, back, home sequence? It seems that this goes deep into the innards of Android, huh?
The only clue I found so far is Overriding Home button for a Car Home replacement app, but this is rated -1 and reported to work in the emulator only. Also I doubt if I could completely abandon the original launcher, as otherwise there is no access anymore to e.g. the USB mass device control to allow new HTML files to be downloaded, the application to be killed and restarted, and so forth.
I'm willing to go for a kludge as well. Maybe a background service could be started that would bring the application to the front again as necessary?
The Home button cannot be overriden. You can write an application that responds to the home intent (that's what a launcher does) but that's all.
Can I achieve this by making my application itself the launcher? How can I then get back to the original launcher upon the home, back, home sequence? It seems that this goes deep into the innards of Android, huh?
Yes. Not too deep into the
innards. You can manually start a launcher by specifying the component, note that this may vary from device to device and user to user, if you're just using this privately you could hard code it, but if you release it you must allow the user to specify their real home app.
/* This should come from a preference that let's the user select an activity that can handle the HOME intent */
String packageName = "com.android.launcher";
String packageClass = "com.android.launcher2.Launcher";
Intent home_intent = new Intent(Intent.ACTION_MAIN);
home_intent.addCategory(Intent.CATEGORY_HOME);
home_intent.setComponent(new ComponentName(packageName, packageClass));
home_intent.addFlags(Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
/* Here you should catch the exception when the launcher has been uninstalled, and let the user save themselves by opening the Market or an app list or something. Users sometimes use root apps to uninstall the system launcher, so your fake launcher is all that is left. Might as well give the poor user a hand. */
startActivity(home_intent);
Detecting home/back/home is a bit awkard because home won't come as a onKeyEvent but instead as a new intent. Simply long-pressing the back button then display a prompt is probably a safe/good approach.
Related
My security company's mobile app (CPI inTouch) allows me to create "scenes" which trigger multiple actions at the same time with a press of one button (e.g. disarming the alarm and unlocking the smart lock on my door). I've also added shortcuts to each of the scenes on my home screen (on my Samsung Galaxy Note9, if that's relevant) so I can launch a scene via the shortcut without having to go into the app itself.
However, having just purchased Tasker, I'd like to trigger the shortcut (or the activity in the app itself) programmatically in a Tasker profile or some other automation app. I've tried plenty of apps that allow you to trigger a shortcut based on an event, but none have these particular shortcuts in the list of available ones. I read that I should be able to use a Send Intent task in Tasker to do this, but I don't know what the intent string would be or where to find it.
In case you can suggest a different way to achieve this, the main use case so far is to have my alarm system automatically disarmed when my phone's morning alarm goes off.
First thing to check would be...
create new task to Launch App,
find your CPI app and if it has a "+" in top right corner of app icon you can long press it to reveal a list of activities.
if your app does not offer those options...
The Tasker dev also has a group of plugins under the AutoApps group, there is one called AutoShortcut that launches shortcuts.
edit: there are apps such as APK Analyzer that can show you the activities and services inside an app and whether or not they can receive intents from external apps.
I am working on an application in which user should be able to use only one application,
he should not be able to switch application using HOME button,
the app. should be closed only when user presses the close button..
I have managed to override return button, don't know how to disable HOME button.
This is not possible to disable the Home Button in android When application is in the background because it might some application always disable the home button if it's possible. So this is the reason developer can't disable the home button when app in background. But In the Activity, you can intercept the home button.
In Activity you can disable the Home key in android. It work till Android 3.x only.
#Override
public void onAttachedToWindow() {
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}
TGMCians is right.
Android will not let an activity and its services run completely alone on your device.
Using Override you can capture button clicks (home, back and menu) when your activity is in the foreground. If an activity/service has full control from the background you would not be able to switch for an incoming sms, e-mails, phone calls, etc either.
Personally I think its dangerous to override the home and back button together, if the activity hangs at some point, you can not get out of the app unless you restart the phone.
Personally, I do override the back key for exit, or return to main screen events, but leave the home button alone.
This is not possible using code at all on iOS, ever.
One usage of HOME button is for emergency situation.
Any house, apartment ... they all have an emergency method, like emergency door (exit), glass breaker (axe, bat ...); it saves life.
Similarly, on Android/iOS phone, HOME button saves users' lives (well, kind of). If HOME button is dead, the phone is considered dead as well as required an instant reboot for refresh. The button was designed for such a purpose, so that developers can't messed-up with everything.
Personally, I'm kinda of being thankful for Android/iOS framework team and whoever thought of this situation on HOME button. It saves my development so many times. I suggest you should think and consider the worst case possible if HOME button is not working in your app; for example, app fails to function as normal, HOME is disabled, so how to back to HOME screen, how to switch to other apps?...
The code provided by TGMCians is not working on 4.0+.
In case, you are working on Android framework, such as building ROMs, building frameworks for manufacturers, ... grep the source code with KEY_HOME and trace inner-depth to find how it works and disable it.
actually, it is possible to block the home button using the next methods:
use of security holes, at least on old android versions. this is done on some locker apps. i think some still work even on newer android versions, but it's a risk and it might be buggy on some devices. i know that "widgetLocker" and "Picture Password Lockscreen" try out those holes. i'm not sure how well they work now with them. best solution of becoming a lockscreen is #2 .
make your app a launcher app, which will handle the home button (user must confirm it of course). an example of such an app is "MagicLocker" , and in fact any launcher app...
using a rooted device. i have no idea how to do it, but i think it's very possible.
not quite a blocking method, but you could have your app full screen and on top (using the TYPE_SYSTEM_ALERT window layout type) , so home button won't be captured, but the user won't see what's going on behind your app. the downside is that any other button won't be captured by your app, since it's not really on the foreground.
I'm working on large project, so there is some logic for saving application state, and then opening correct activity(fragment) when it comes from background.
But anyway, I've found that if user navigates through my app and then minimize it - android opens it from background in different ways in following cases:
User taps on app icon (behavior: user see home activity, doesn't matter where he was, when application was minimized)
User select app from android "recent apps" (behavior: user see exactly what he saw, when the application was minimized)
So, what is the difference between launching application from background by this two ways? I always thought, that it is the same mechanism, but, obviously, I was wrong.
Thanks for any answers
You should pay atention on the folowing docs Activity and Tasks. In short words: if user start app from recents you will receive onRestart before onStart (without onCreate it means that your app was just "suspended"). You able to save screen state using onSaveInstanceState(). But in general starting from icon and from recents - different application behaviors and you should provide proper code for this ways.
UPD
As described below root cause of unexpected behaviour was additional lunchmode attribute.
From what I experience as an Android user, both are same.
The difference we usually see is how we close the app
Press back button until app close / finish()
On this state no matter how we open the apps it will go to the main screen
Press Home button
On this state depend on the app. If the app does not handle any Activity the app will same with the first state. But if the app handle something like when onPause() the Activity then finish() the apps, then whatever you open with app icon or recent apps will provide the same result.
Correct me if I am wrong
In iphone when we exit app and start app again by clicking launcher icon the app start from screen which was open last time before exiting app.
We can achieve same in android when we exit app using center or home button on android phone. In android app if app is exited by pressing home button and started again by clicking on launcher icon the app start from activity which was open last time before exiting app.
Is that functionality similar to iphone in terms of keeping app in memory longer? Will that work in android all time because I think android system will remove app from memory after sometime or will it remain in memory longer? Can I depend on this functionality in android and expect it to work all time.
I have a project in android which client has asked me to have iphone like functionality if we exit app and start app again it should open from screen which was opened last time before exiting. Now this is possible in android only if we use centre button. And also if user has exited using centre button and started it again, app should check for user current location and do some other operations. If app is launched and user navigate to any activity is there any way to check if app was exited using back button or centre button so that I can run code if app is exited using center button.
Thanks
We can achieve same in android when we exit app using center or home button on android phone.
The HOME button does not "exit app".
The HOME button brings the home screen to the foreground, just as the CAMERA button (where available) brings the camera application to the foreground, the CALL button (where available) brings the dialer to the foreground, tapping on a Notification may bring something else to the foreground (e.g., SMS client) based on the Notification, etc.
In android app if app is exited by pressing home button and started again by clicking on launcher icon the app start from activity which was open last time before exiting app.
No. If you tap on a launcher icon, and the app's process is still in memory, the existing app instance will be brought to the foreground, returning you to whatever activity you had been on. If you tap on a launcher icon, and the app's process had been terminated to free up RAM for other apps, you launch a fresh copy of the app and bring up whatever the ACTION_MAIN/CATEGORY_LAUNCHER activity was that the user tapped upon.
Will that work in android all time because I think android system will remove app from memory after sometime or will it remain in memory longer?
The length of time that a non-foreground app's process will be in memory is indeterminate and will be based on what is going on with the device, plus the device capabilities (e.g., how much RAM). I suggest you read more about the process lifecycle.
Now this is possible in android only if we use centre button.
It is not possible "if we use centre button" (what Android developers refer to as the HOME button). It may happen automatically, but if the app's process has been terminated, it will not happen automatically.
If app is launched and user navigate to any activity is there any way to check if app was exited using back button or centre button so that I can run code if app is exited using center button.
You should not care whether the "app was exited using back button or centre button".
You should care whether you have your data and how old that data is, refreshing it if it is stale.
Whether the user left your app via HOME, BACK, CAMERA, CALL, a Notification, the recent tasks list, an incoming phone call, by smashing their phone to bits with a rock and replacing it with an exact duplicate, or by any other means, should not matter to you.
To draw an analogy, think of a Web app. In a Web app, you care about whether you have a session cookie and whether that session is stale (e.g., to force a fresh login). Whether the page request came because the user clicked a link within the app, or clicked on a link from a third party site pointing to your app, or refreshed their page, or used a bookmark to get at another page in your app, or double-clicked on a desktop icon that brings up your app, or right-clicked on a link and opened a fresh tab, or anything else, should not matter to you.
Review the Android Activity Lifecycle at http://developer.android.com/reference/android/app/Activity.html. If you do nothing, you have no guarantee of your app starting at the same point it left off, however you have control here. You can, for example, overload the onPause() method to save your state to a file, and onResume() to restore it.
The question I'm about to ask may seem dangerous for the user, so here's the story before the question:
I'm working in a compagny that tries to sell Galaxy Tabs to schools (children under 10). So, I've been asked to develop an application that starts on boot showing a login screen. The child HAS to log in before he's allowed to use the tablet (just like logging in a computer).
My application starts on boot, shows the login screen, all buttons are blocked (the kid must not be able to use the tablet before the application lets him) except the home button.
fortunately, it seems impossible to block the home button.
I've been trying to rebring the application to front when onpause/onstop is called, this kind of hacks.
So my question is : Can I prevent an user to quit my application until I let him do so?
I know this sounds like a virus, I'm not really happy to be looking for this kind of solution either.
You have to build a custom Home screen, and then set it as the default Home application.
EDIT: see more on this previously asked question (at How can I create a custom home-screen replacement application for Android?). You can just make your authorization the default Home application, then when they log in it forwards to the regular Home screen. If they hit the home button your app gets called, can check if they have logged in and if they have will just send them to the regular home screen.