While developing an Android app targeting all versions above 4.1, I observed that uninstalling my app and installing it again does not clear its data.
The app is designed to store the details that it asks in its first screen.
After uninstalling and installing again in OS version 4.4.4, the app prompts the user to fill in the data, which is normal. However in version 6.0 the same install/uninstall sequence bring backs the data originally input.
I tried to ensure by visiting /data/data/my package folder to see the database is gone after uninstalling and indeed that folder gets deleted during uninstall.
I tried to delete the app by visiting the settings page, through Titanium Backup and the results are same. The device is rooted Nexus 5 running v6.0.
What could be the reason for this strange behavior?
It's because Android 6 has automatic backup. You need to tune android:allowBackup and android:fullBackupContent in your manifest <application> tag if you don't want your data backed up or if you want to include or exclude some resources. It's not a bug.
More about AutoBackup on Android here.
greywolf82's answer is correct but I want to add some info to this.
When developing my Android app (using Xamarin), I noticed that whenever I'd re-launch the app from Visual Studio, my data would revert back to data from a few months ago. It didn't matter if I simply stopped and re-ran it from VS, or if I completely uninstalled the app and reinstalled it.
It's also worth noting that we never explicitly told the app to store a backup.
The backup also seemed to overwrite newer data when launching from Visual Studio, and we have reports of users using the release build of our app and also getting newer data overwritten by the backups.
Since I don't know exactly when backups and restores occur this feature seems to cause only problems.
We've modified our AndroidManifest by adding the following two lines:
android:allowBackup="false"
android:fullBackupOnly="false"
After adding them, our AndroidManifest contained the following xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.XXXXXXX" android:versionName="8.0.0" android:installLocation="auto" android:versionCode="439">
<uses-sdk android:minSdkVersion="14" android:targetSdkVersion="24" />
<application
android:label="#string/appName"
android:icon="#drawable/icon_small"
android:installLocation="internalOnly"
android:largeHeap="true"
android:allowBackup="false"
android:fullBackupOnly="false"
/>
...
</manifest>
Once we explicitly set the value to false, all seems to work. I'd expect this to be an opt-in feature but...seems like it might be on by default for apps which don't specify the value either way.
You should check your device's Backup and Reset settings, and turn off Automatic restore (when reinstalling an application, backed up settings and data will be restored.)
Turning off auto-backup is different from the auto-restore. If you think it will be helpful to turn on auto-backup for your application do so. But if you think this will make end users who are not aware that the auto-restore feature of their device is turned on, feel free to turn it off.
In my case, I turned off the allowBackup feature, but since I already had a backup of the previous version on the Cloud, it still kept on restoring.
See image as reference for a Samsung device on Android 6.0. Other devices and versions may have a different screen. See image below.
Automatic Restore Setting under Backup and Reset
Just adding to this, we found that in Android 9 (on a HMD Nokia device) that the assets were held, even after deleting the app through the interface and through adb.
The answer of adding:
android:allowBackup="false"
android:fullBackupOnly="false"
Obviously, this is not a new answer - but an observation for people who were in the same position as us.
I recently needed to take advantage of these features, I was able to uncover documentation and upon extensive testing this is what I have been able to deduce:
Android:allowbackup - will backup local app data on the device it is located on.
Android:fullBackupContent - is used in conjunction with Google's backup restore api and CAN be controlled via an xml file to specify what exactly to backup, as well as a BackupManager class you may implement for further control over the process.
However the documentation states, and I have confirmed with testing, that a restore will only occur either when the device is restored and the restore app data process is triggered. OR it will also restore when the app is sideloaded through adb, which is what we do when we run the app for testing or debug on our devices through Android Studio. Note that if you set android:allowbackup but do not configure android:fullBackupContent with a Google api code then the apps data only gets stored locally, whereas if you configured it properly then if your app was backed up and you get a new device the apps data was stored on the cloud so it can be restored on a new device.
If you are targeting android 10 then you have to put android:hasFragileUserData="true" in application tag of AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
<application
android:name=".MyApplication"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme"
android:allowBackup="true"
android:hasFragileUserData="true">
.....
</application>
</manifest>
android:hasFragileUserData is a new manifest setting (I’m guessing on ). “If true the user is prompted to keep the app’s data on uninstall”. This seems ripe for abuse, but I can see where it might be useful for some apps.
See https://commonsware.com/blog/2019/06/06/random-musings-q-beta-4.html
Adding android:allowBackup="false" under application tag in Manifest file solved my issue.
Here goes the android documentation for Back up user data with Auto Backup
I also added:
tools:replace="android:allowBackup"
to override same option in a used component
This answer summarizes multiple other existing answers, and includes recent details as of Android 12 being introduced, and includes instructions for clearing existing app backup data generated from a device.
For more information, see
https://developer.android.com/guide/topics/data/autobackup#EnablingAutoBackup
https://developer.android.com/about/versions/12/behavior-changes-12#backup-restore
https://developer.android.com/guide/topics/manifest/application-element
http://android-doc.github.io/preview/backup/index.html (for clearing existing app backup data stored in Google Drive from a device: Settings > Backup > toggle Google One backup off then back on again, then try uninstall/reinstall again)
As a side note, some of the other answers suggest android:fullBackupContent="false" but that doesn't seem correct anymore since that is currently meant to specify an xml file of a specific format, not a true/false.
These attributes to <application> allow for disabling or configuring specifics for Android auto-backup functionality.
<application
tools:replace="android:label, android:icon, android:allowBackup, '...any other attribute you want to override with a value you set in this file for in case dependencies set them to other values...'"
'...your other attributes set here like android:label and android:icon...'
android:allowBackup="false" '...default is true, and setting this false prevents data backups of any kind (except device to device transfers if your app targets Android 11 (API 30) or higher)...'
android:fullBackupContent="#xml/backup_rules_android_11_and_below" '...optional, for Android 11 and below, referring to a file res/xml/backup_rules_android_11_and_below.xml you need to create...'
android:dataExtractionRules="#xml/backup_rules_android_12_and_above" '...optional, for Android 12 and above (fullBackupContent still needed along with this, assuming you support Android 11 and below), referring to a file res/xml/backup_rules_android_12_and_above.xml you need to create, with a slightly different required xml format...'
android:fullBackupOnly="false" '...optional, and default is false, but if set to true this field description says it enables auto backup on Android 6 (API 23) devices or higher (I am not sure how this matters compared to the more broadly reaching allowBackup)...'
android:hasFragileUserData="false" '...optional, and default is false, but if set to true this field description says it gives the user an option when they uninstall the app whether or not to backup their app data...'
>
'...contents of application element...'
</application>
The <application> changes only affect creation (or lack of creation) of future app backups; any existing app backup data will still exist and be used until overwritten or cleared (see above for instructions to clear that data for a device).
Just change android:allowBackup="true" to android:allowBackup="false" in manifiest.xml. It will be worked.
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
<application
android:allowBackup="false"
android:icon="#mipmap/app_icon"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
</manifest>
If I wanted to research how and where permissions [requested in the Mainfest.xml] were used in an Android app for the purposes of removing them is there an easy way of doing this? Does lint or findbugs offer some sort of support for tracking permissions used/abused in a project?
I came from the future to save your lives.
Here (in the future), LINT does check for missing permissions as you can see on LINT checks.
So, go to your AndroidManifest.xml and remove all tags <uses-permission> using Android permissions (meaning, don't delete permissions that belong to your app, such as UA_DATA and C2D_MESSAGE).
Then run LINT analysis. Click on Analyze then Inspect Code...
Look under Android -> Constant and Resource Type Mismatches
You should see all missing permissions.
Then you can just right-click them and select Apply fix "Add Permission". If you select this option, Android Studio will include one permission for every error. So you'll end up with multiple copies of the same permission on your Manifest file, just delete the duplicates. You can do it manually too.
Here is the description of the LINT rule:
ID ResourceType
Description
This inspection looks at Android API calls that have been annotated with various support annotations (such as RequiresPermission or UiThread) and flags any calls that are not using the API correctly as specified by the annotations. Examples of errors flagged by this inspection:
Passing the wrong type of resource integer (such as R.string) to an API that expects a different type (such as R.dimen).
Forgetting to invoke the overridden method (via super) in methods that require it
Calling a method that requires a permission without having declared that permission in the manifest
Passing a resource color reference to a method which expects an RGB integer value.
...and many more. For more information, see the documentation at http://developer.android.com/tools/debugging/annotations.html
I'm using Android Studio 2.1.2.
In your app manifest file you should have a tab "Merged Manifest" there you can see your final manifest and the permissions you request you can click on a permission to see where it came from. (who added it - ex': sdk or what code it came from)
There is also a simple way to remove a permission by adding to manifest:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"
tools:node="remove" />
Also remember to add the tools at the top:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="...">
The way I would do it for an app for which I didn't write the code would be to remove the permissions one by one and test the app end-to-end each time. When it fails, narrow it down. If not, that permission may not be used.
You will have to try removing them one by one and checking i fthe app still works OK. This is not checked by lint in any way (it should be).
When they come back (they are currently down), you can upload your apk to this website (if that's ok with you) and let them statically analyse the permissions you are using: http://www.android-permissions.org/
Best way is to understand what the may actually do. If it is ever going to use the camera then you know you need the camera permission.
Or you could just learn what your app does and then go through the permissions and see which ones are extra. What does your app do, what phone features does it use. There should be some documentation somewhere on what it should do and what methods are in there
This is my problem:
I have an application that requires a certain persmission (Write-SMS) that will of course only function on phones. Now, the app requires that permission for a feature that will be disabled on tablet versions but it won't let users install the app on tablets.
I guess my question is this:
Can I easily create a second manifest for the tablet version, that will be roughly the same as the phone version but without the persmission?
If I'm doing so, is there a way to check what manifest version is being used? I might want to add features to the tablet version that are tablet exclusive and vice versa.
All of course preferibly in one apk, that gets exported and signed once. Thanks for your help in advance!
Simple add:
<uses-feature android:name="android.hardware.telephony" android:required="false" />
To your manifest. The SMS permission automatically asks for a Telephony feature. Adding this tells android that even though you ask for this feature, you don't need it.
Be sure to add an if-else check to see if you can sens SMS from the device before doing so.
I think you must check it in the actual method itself, because permissions can be optional or compulsory, but that's it, not distinguishable for different devices..
I have a app which has 2 widgets, lets call them SimpleWidget and ListWidget.
ListWidget makes use of android 3.1 (api level 12) features.
What I would like to do is register both widgets if the device is 3.1 or above.
If it is not than I would only want to register SimpleWidget.
As the code stands now the widgets are defined in my app's AndroidManifest.xml file.
I can't figure out how I could filter this by sdk level.
The only solution I have found so far would still display both widgets (in android's add widget page) even on pre 3.1 devices (in which case I relegate ListWidget to a SimpleWidget).
Am I missing something?
For example can I register widgets in Java code (maybe in the app's onCreate method) instead of in the manifest file? (seems unlikely since the info is needed before the app is ever run).
My goal is to modify the Launcher application and dynamically modify and change the theme.
I saw several 'home' apps at http://www.cyrket.com/p/android/com.stain46.taghome/. It looks like they took the default Home(Launcher) and modified it. How did they do that? What do I need to modify to achieve the same thing?
I have done this with the ICS launcher. You also need to do quite a number of code changes to get it to compile as a normal app because it uses a lot of private internal APIs (despite what Google may have implied). You also need to change the package name. There are two limitations I've found:
There's a filter called TableMaskFilter that isn't available to normal apps. I think this allows the app drawer to be semi-transparent, but I removed uses of it and it looks fine I think.
More critically, it appears there is no way to replicate the widget-adding experience because it requires a permission that only system apps can have. See this question.
Anyway, I put my source here. It compiles and works on the official Galaxy S2 4.0.3, but if you try to add widgets it will crash.
Note, when you're changing the package name, there are places that Eclipse's refactor doesn't notice (e.g. XML layouts). I recommend you do a global text search/replace instead.
The standard Launcher is open source so you can definitely grab it and modify it the way you want. For your app to be used as the Home Screen you will need to specify the correct Intent filter in your AndroidManifest.xml and the user will have to choose your app when they press the Home button. Why don't you grab that code, play with it and come back when you have more questions and more of an idea of what you want to change.
Here i found one stable version Launcher2
I have sharing that GitHub repo. HERE
WIKI of this project :
This project contains the code for the Launcher app that ships with Android Jelly Bean (API 16).
Some minor changes were required from this source code to remove the use of private APIs. These changes have been marked by "// AOSP Change"