I have an app where I should fill data on some edittexts or spinners. After that I have some buttons where I should take some pictures, sometimes there's 2 or 3 pictures. Im using a Camera Intent.
The problem is that SOMETIMES just in SOME PHONES, when the app comesback from Camera app it deletes all data filled on the views, and it deletes the pictures already taken. So it crush the activity.
I'm pretty sure its not the orientation, since IM using this on the manifest.
<activity
android:name=".MainActivity"
android:configChanges="screenLayout|orientation|screenSize">
I have nothing on the error log. One solution is when I delete data from Google Play Services or I unistall it and reinstall again. This fix the problem for sometime and then it happens again.
I dont know what else could it be. On the activity Im using Camera and Im accesing User location.
Camera app takes a lot of memory and on low-end devices with less memory system might kill your app to free some memory.
android:configChanges is more of a hack rather than a correct solution, it does not prevent a case as described above.
You should implement correctly activity life time cycle functions, by saving instance state in onSaveInstanceState and recreating it in onCreate. There is no other way around.
To test such cases, go to developer settings and disable applications in background. This way each time you will click on home button of your device, your app will be killed, and going back to it it will be recreated.
Related
I've an app that should always start from the initial activity when its icon on home screen is pressed.
I've managed to make this work in every situation by finishing the current activities when the application was going to be exited.
But there's a point in the app where this is not possible unless I ruin user experience a lot, which is if the user opens an ad offered by the app and then either goes to home screen (via home button for example) or press back button to keep on using the app.
In both cases the following events are fired: onAdLeftApplication-> onAdClosed-> on Resume (although as how I understand documentation onAdClosed shouldn't fire in the case of opening the browser, but well... it happens).
With this I find no way to differentiate between the 2 cases, although there might be an event, that would allow to differentiate them-
Think the easiest way to solve this problem is to always force that if the icon is pressed what is fired is never onResume, always onCreate, this way I don't have to worry about the app not starting from beginning for whatever, by default it's going to do that.
But maybe what I'm mentioning is not possible anyway, so maybe some event like the one I'm mentioning might help with this problem. I'll happily listen to any recomendation about that.
What code is required to keep an app live when it is "pushed" to the background?
My app USED to behave this way. If a user multitasked or hit home, my app would minimise, and they could later return to it. Now, and I have no idea what change I made to cause this, my app is closed by the Android system whenever it is minimised.
I have checked memory, and it doesn't seem to be an issue. My app is actually using LESS memory now than previously.
When the app is minimised and closed, OnPause and OnStop are being called for the current activity, but onSaveInstanceState is not.
SOLVED: It was caused by android:noHistory="true" in my manafest
In Android when you hold down the home button you can bring up a task list of your recent apps. And each "card" in the task list should have a preview of the app. However, this time I opened the task list and the previews were blank (except for the app title).
I had the phone Settings in the task list and every time I would tap on the task and try to open it in would close immediately.
I also had this app I was developing and when I tapped on the task to open the app my RecyclerView wasn't showing anything, when it should be.
I also was playing AngryBirds 2, so was it that Android had silently killed those apps for memory? If so, does onCreate() of the killed apps get called again when this happens?
Edit: I just noticed if you close an app too quickly when it's transitioning to an Activity you can get a blank preview.
Edit 2: So to answer my question, after referencing the Activity lifecycle diagram this is what I found. When another application needs memory, the app's process will be killed and when the user navigates back to the app, onCreate() will be called again. However, that doesn't explain why I couldn't reopen the Settings. And I have no idea how to reproduce this weird behavior!
Ok after some debugging, I found out that Android did indeed kill my app because it needed memory. When you resume to your app however, onCreate will be called with a savedInstanceState that is NOT null. I had some logic that required savedInstanceState to be null and therefore my RecyclerView wasn't populated.
To recreate this scenario of Android killing my app I had to open a ton of apps lol. Is there way I can reproduce Android killing my app without opening all those apps? Hm...
From the beginning of the APP development, I found that if I re launch the APP, the APP crashes and nothing gets displayed. I think it has something to do with the resource that is assigned to the APP and it trying to restore its previous state and it is failing to do so.
I see that, in many APPs, when it re launches the view is reset to its first screen. I would like to do the same in my APP.
Any suggestions on how I should be handling this ?
clear up memory ?
attach an event before-close and on-launch (or on-relaunch) ?
reset APP view to home screen ?
This is the first APP I am building (happens to be in Titanium). Therefore my fundamentals of APP development are weak.
Any help would be greatly appreciated.
I'm not sure what you are doing in your app, but I'm not seeing that in my Titanium apps. My users probably leave my app running/paused for days and then resume them as needed. Until their device runs out of juice, I'm pretty sure they never restart my app. Perhaps a module you are using?
There are events you can handle that will allow you to take an action when the app is put paused and when it is resumed. You can write your code to reset the app to the starting screen, which I'm partial to that idea as well. I'm not aware of a call you can make that will essentially restart your app.
The events you can handle.
Ti.App.addEventListener('pause', _.bind(this.exit, this));
Ti.App.addEventListener('close', _.bind(this.exit, this));
Ti.App.addEventListener('resume', _.bind(this.resume, this));
You would have to write the action taken when these events happen.
Code is from the https://github.com/appcelerator/Field-Service-App. This app has the hooks, but doesn't implement any actions for them. Check out the alloy.js file.
I want to create a password-protected android application. The password should be asked when the task is started or when it comes to foreground.
The complex part is that my app can invoke device inbuilt camera application to capture photo/video, so I cannot control that activity.
So the behavior should be that whenever user starts/returns to my app then password should be asked except for the scenario when he is returning from camera that I sent him to in the first place.
I have thought following ideas, but none of them solve my problem completely, the best one I could think of is
1) Set a flag(flagA) while sending the user to camera, then in a service keep checking that the foreground app is our app. When the foreground app is not our app then set another flag(flagB) to indicate that our app has gone to background. When the app in foreground is our app again, then check if flagA is false (we didnt send him to camera) and flagB is true (app is coming from background). Then show the password screen
Problems
1) The polling interval must be small like 3-4 seconds, so that foreground is detected quickly. This drains the battery.
Thanks
A few ideas come to mind.
This is just a quick idea of mine so it might not be useful but considering you haven't told us what you've already tried / have in mind we don't have a lot to go with.
You'll need at least 2 Activities to handle the whole password idea.
Firstly, when you start the app, run Activity A. This will ask for the password (assuming the password is always the same). If the password is correct -> start an intent with Activity B.
If the password is incorrect, close the app.
In B, give the user the option to invoke the camera. After using the camera, return to Activity B.
It doesn't get much better with the amount of info you've given us, but it should give you an idea on how to start.
I have solved the problem partially
1) Have a static long variable to track the time between onPause() and onResume(). During normal app operation this time is under 1 second, but if app goes to background and comes to foreground then this duration is more than 1 second. So in onResume() if the duration is more than 1 second then show the Password screen.
2) To handle the camera problem I am having a flag to detect whether I opened the camera, if that flag is set then dont ask for password in onResume().
This solution is not fool proof but works in most scenarios.