I am building a Lock Screen that doesn't replace the stock Lock Screen, but instead allows the user to use "Swipe" to unlock and then shows my Lock Screen.
Therefore, I would like to know how I could possibly launch the Lock Screen immediately after the user has swiped to unlock, as a non dismissible activity.
By setting the activity's category as home, I was able to restrict some functionality but not entirely as the user could pull down the notification panel and enter apps or even press the recents apps button.
Related
I am working on a small app. When the user presses the app icon it starts activity A, which in turns starts activity B. Activity A then completes. B is set up as a main menu and can start other activities: the user can navigate back to B with the back button.
If the user navigates back to B and presses the back button the app moves into the background and the user is at their home screen. I have not overridden anything; this is the normal navigation.
At this point, if the user presses the app icon the app restarts. I understand that when the app is in the background the OS can close it for memory purposes, but this happens every time - regardless of how much memory. Is there a way to change this behavior? I already figured out how to stop this action with the home button with:
if (!isTaskRoot())
But I need to stop the action on the back button.
You can override onBackPressed() of Activity B like this,
#Override
public void onBackPressed () {
moveTaskToBack(true);
}
The app will be hidden when the user presses the back button, but it's state will remain the same. And when it is reopened, it will appear just as it was when you left it.
I'm trying to find out what the difference is in the activity lifecycle when a lock-screen is enabled versus disabled.
Scenario A (no lock-screen)
App is running
power button is hit to turn display off
power button is hit to turn display on
App is immediately resumed
Scenario B (lock screen enabled, swipe to unlock)
App is running
power button is hit to turn display off
power button is hit to turn display on
Swipe screen to unlock
App is resumed (but we are getting a bug in the display, which is where we are trying to find the difference)
I have printed out the activity lifecycle for both scenarios and they show up identical for both scenarios.
What might be the difference in the lifecycle that would cause this different behavior when using lock-screen versus no lock-screen?
Take a look at this documentation. It could be that the lock screen would imply that the app process is killed and therefore data is lost (which is necessary to present the page and therefore the app crashes). I would suggest to debug the activity states to find the answer you're looking for.
You can test it with writing Logs into onResume(), onCreate(), onPause(), onDestroy() etc.
Also pressing Power button and and opening LockScreen changes the devices screen orientation into "Portrait" mode(Phones and tablets with locked rotation only). It may cause different reactions you are mentioned about.
I am writing an app for a child's emergency phone that will allow them to call preprogrammed contacts by pressing a button on the app. The problem is that when it goes into the dialer app the user will have access to the contacts and the other settings available within the dialer. I want to prevent this. Essentially I want to have it so that the only button the child can press is the End Call button which will stop the dialer activity and drop the phone back to my custom home app. Is this possible? Or will I have to replace the entire dialer app (which, it seems, would be less than a trivial solution).
I have an Android app where I want to track when the app is paused or resumed.
paused: User pressed the home button and the app is still running in the background.
resumed: app runs in background and user opens the app.
How can I being notified when my app was paused/resumed?
paused: User pressed the home button and the app is still running in the background.
I am going to guess that the initial state is that one of your activities was in the foreground at the time the HOME button was pressed.
On the whole, there is no notion in Android of an "app" being in the foreground or the background, though we sometimes use that phrasing as shorthand for other scenarios.
Whatever activity was in the foreground will be called with onPause() and onStop() when the user presses HOME, but those events are also called in many other scenarios (e.g., user presses BACK). onUserLeaveHint() will be called when the user presses HOME but not BACK, but onUserLeaveHint() is not called in other scenarios (e.g., incoming call screen takes over the foreground). Whether onUserLeaveHint() will meet your requirements, I cannot say.
resumed: app runs in background and user opens the app.
onStart() and onResume(), at minimum, will be called on your activity that takes over the foreground. Those will be called at other times too, such as when the activity is coming onto the screen for the first time. There is also onRestart(), which will be called only if the activity is being started after having been stopped (i.e., after a prior onStop() call), which will weed out the newly-created-activity scenario. However, onRestart() will be called in other scenarios as well, such as part of a configuration change (e.g., screen rotation).
In general, what you are seeking is not really part of the Android architecture. You may need to approach your problem in some other way.
In you Android activity you can override the onPause and onResume methods.
See the documentation on Lifecycle Callbacks for a list of other lifecycle callbacks that you can implement.
i want to develop an android application to locate a mobile no.Obviously it cannot be done without user approval.
Basically i need the GPS coordinates of the other user.So my idea is to, after selecting a contact from the list,when i click on locate Button a automatic message/notifaction is sent to the other user asking for his/her permission to Allow/Deny.Once the user clicks on the allow button an automatic msg will be sent to the locator giving the longitudes,latitudes of the mobile which i can locate using GPS
If I understood you well, on the receiving end, a Service will be monitoring for Events (on Bluetooth or Wifi) and should popup a dialog requiring user to accept or deny a transaction.
You can quite easily make an Activity that polls for Event (or better, make a bounded background Service Message your Activity when a new Event has been detected) and display a popup AlertDialog. If you design it this way you will need your Activity to be active and running (i.e. displayed).
If you need your application to get user attention even when your application is not displayed, you will not be able to do so: you can not (nor should) directly start an Activity from within a Service. You will have to use Notifications and/or a Toast message to unintrusively notify your user that something requires his/her attention. Notifications appear in the status bar and can be used to launch your Accept/Deny Activity.