Database Users

[Q] Android app auto starts again when device rotated

Hello all,
I've written a simple audio player app and testing it in Samsung Galaxy S.
It is a simple app with can create playlist and some buttons to play the mp3 file.
However, there's a funny bug in it.
After starting the app, whenever I rotate the phone, the running app will launch another instance of the app. If I rotate again, another instance (3rd) would be started. So u can hear 3 copies of the same audio being played simultaneously.
What could be wrong with it?
Is there some code which can prevent program re-entry?
Thanks.

It's not a bug, that's the way andorid OS works. You need to account for this in OnCreate for your activity. I assume you are spawning off the actual playing of the MP3 in a thread or service. You need to check if the service is already running in OnCreate and attach, else spawn a new one.

Hello Gene,
How do I check if an activity is already running?
I could not find the answer on the android developer page (the topic on application fundamentals).
And no, I'm not converting it to a service yet as this is my first app.
Haven't explore service yet.
Thanks.

I read on another article, a simple way to prevent this is to add overwrite the onConfigurationChanged function
@Override
public void onConfigurationChanged(Configuration newConfig) {
//ignore orientation change
super.onConfigurationChanged(newConfig);
}
and modify the androidmanifest.xml
<activity android:name="selectCategories" android:configChanges="orientation|keyboardHidden"></activity>
But it still launch multiple instance of the app.
Thanks.

This is a good question and should be in an FAQ somewhere.
As already mentioned, changing the display orientation basically restarts your app. Read the Android dev page on Activity lifecycle for more info.
A short answer for your question is: the Bundle parameter for onCreate() will be null when your app is first run. When your app is paused and restarted, that Bundle will be non-null. You can store data in that Bundle by overriding onSaveInstanceState(), then check for that data in onCreate(). It's a good idea to learn how to do this (save/read app data on pause/restart). Once you start testing apps by rotating the display at various times, you'll find a lot of them FC at unexpected places.

This is indeed a topic that keeps surprising people who are new to android (ahem, like me 4-5 months ago ).
The solutions above are perfect, however in certain situations there's another trick that might make your life much easier. I suspect it won't help you in this case, but it might help others who tackle the problem and see this thread.
Certain applications, mainly games, should be fixed in a single orientation. I.E. you won't be playing angry birds on portrait - that game is locked to landscape, as it should be. In order to lock your activity in a certain orientation you add this attribute to the manifest under the Activity tag. So a standard activity might look something like that, combined with the ignore tag from the previous posts:
Code:
<activity android:screenOrientation="landscape" android:configChanges="orientation|keyboardHidden"
android:name="whatever">
The great thing about this combination is that your activity will not restart at all when the phone is rotated. Of course, for a standard activity you'd usually want to support both landscape and portrait, but if you need your app to be in a fixed orientation this is the way to go - no weird FCs or annoying bugs

Hi,
How do I check the bundle?
And also, what to do if the bundle is not null? Just return?
Thanks.
regards
r_p_ang said:
This is a good question and should be in an FAQ somewhere.
As already mentioned, changing the display orientation basically restarts your app. Read the Android dev page on Activity lifecycle for more info.
A short answer for your question is: the Bundle parameter for onCreate() will be null when your app is first run. When your app is paused and restarted, that Bundle will be non-null. You can store data in that Bundle by overriding onSaveInstanceState(), then check for that data in onCreate(). It's a good idea to learn how to do this (save/read app data on pause/restart). Once you start testing apps by rotating the display at various times, you'll find a lot of them FC at unexpected places.
Click to expand...
Click to collapse

[Q] Question about automated reply function

Hi guys. Developing an app with a simple enough concept. I want to be able to launch an app that has a textbox that a custom string can be saved to. When an sms message is received, the string is sent back automatically as a reply. So far I have an EditText in the xml and set up shared preferences so the string stays persistent if you exit back to the apps "main menu".
I have seen alot of sample code online but am struggling to get a decent example of my specific requirement that I could implement to what I already have in place.
Can anyone advise on how I could do this with the most ease?
I have researched smsmessagingdemo.java online and it's not really what I need.

And the "simple concept" is always a "killer" for programmers as they usually end up being hard to implement! LOL Such is the case here.
The app idea is a good one; kind of like your own personal "call waiting" app for texts.

just fyi
There's already a few apps on the market that do something like this. Otterbox is one example: https://market.android.com/details?id=com.otterapp.otter I think state farm has an app that does similar.

Detect Package Launch

I am working on an application and I need to be able to have a service that can detect when applications are opened, and take action based on that.
I have looked everywhere, and have not found a way to do so. I have read documentation on broadcast receivers, intent handlers, I found nothing.
I did however, find an app that can do so. App Protector. It allows password protecting certain applications.
Can anybody please point me in the right direction?
Thanks!

this is actually a very good question. a BroadcastReciever only gets Intents directed at it, and wouldnt see Intents for other classes and Packages.
ill be very interested to know the answer

killersnowman said:
this is actually a very good question. a BroadcastReciever only gets Intents directed at it, and wouldnt see Intents for other classes and Packages.
ill be very interested to know the answer
Click to expand...
Click to collapse
Well I was looking for a BroadcastReceiver that was sent out by the system to indicate that an app was opened, but I did not come across anything.

this isnt possible.. to be able to monitor all intents would make android extremely insecure
http://groups.google.com/group/android-developers/browse_thread/thread/54ddc9d36a24d77b
but there are ways to know when an application is launched. you just have to be creative.
this will give you a list of all the applications running.
Code:
ActivityManager am = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> runningAppProcessInfo = am.getRunningAppProcesses();
however to know when an app is launched you would need a timed loop and then check between versions of the List to see if there is a new app. this would suck the juice and be inneficient
AppProtector seem to access the eventlog. maybe you could have a ContentObserver attached to the event log
http://developer.android.com/reference/android/util/EventLog.html
http://developer.android.com/reference/android/database/ContentObserver.html

killersnowman said:
this isnt possible.. to be able to monitor all intents would make android extremely insecure
http://groups.google.com/group/android-developers/browse_thread/thread/54ddc9d36a24d77b
but there are ways to know when an application is launched. you just have to be creative.
this will give you a list of all the applications running.
Code:
ActivityManager am = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> runningAppProcessInfo = am.getRunningAppProcesses();
however to know when an app is launched you would need a timed loop and then check between versions of the List to see if there is a new app. this would suck the juice and be inneficient
AppProtector seem to access the eventlog. maybe you could have a ContentObserver attached to the event log
http://developer.android.com/reference/android/util/EventLog.html
http://developer.android.com/reference/android/database/ContentObserver.html
Click to expand...
Click to collapse
Interesting.
I also found this:
Code:
String str = ((ActivityManager.RunningTaskInfo)this.am.getRunningTasks(1).get(0)).topActivity.getPackageName();
It's one of the things App Protector uses
It starts a new intent, pointing to their application, and passing the parameters of the package you tried to run

Take a look at Tasker it can defiantly do this.

rujelus22 said:
Take a look at Tasker it can defiantly do this.
Click to expand...
Click to collapse
He doesn't want it for scripting, but for use in his own program.
From something awesome

[GUIDE] Using the Share Intent

Hello everyone,
While making an app, I wanted to let the user be able to share some content (shameless plug: from a clearable EditText). So, I looked up how to do this.
In this thread, I will share (pun not even intended) with you how to use the Share Intent yourself, so that your users can also quickly involve anyone they know in what they're doing.
There are some things that I am going to assume you've done:
- You have made your base app
- You have a Button done and set up, only needing a method to execute the Share Intent.
Now, let's get to it!
Step 1 - The method:
First, you have to set up the method. As always, give it a nice and descriptive name, so everyone (including you later, believe me that you'll need it) knows what it does.
Of course, this just follows standard syntax. I'm going to name it share, because simple!
So, you'll get this:
Code:
private void share() {
// This is the method where we share some content
}
Step 2 - The Intent:
You want to make sure that Android recognises your Intent as being a Share Intent. Of course, because of the flexibility of Intents, this is also easily done. Just declare another parameter, which isn't the usual set of Classes.
My Intent will be called shareIntent.
Like so:
Code:
Intent shareIntent = new Intent(android.content.intent.ACTION_SEND);
Step 3 - The type:
When sharing content in Android, you have to let the system know what you're sharing. Naturally, it has to react differently to different types of content. An image can be handled by certain apps, while others can only handle text. Apart from that, the apps have to process the items differently.
This is done by declaring the MIME type, which are unique identifiers for different data types.
Some possible types are text/plain, image/gif and video/mp4.
In this case, we are going to share some text. This is done by adding the following line under the Intent declaration:
Code:
shareIntent.setType("text/plain");
With the setType method, you could target specific apps. However, this is obviously not a good idea. If a user doesn't have that app on their phone, it'll cause trouble. Therefore, just use the right type and let the user select the relevant application.
Step 4 - The Content:
Now for the real work. What are you sharing? Of course, text! But you have to give the Intent that text, because it won't just snuff it out by itself.
How do we do this? Simple, again.
Just create a String and use that. Of course, you can hard code a String in the Intent, but it's best to use a variable. After all, you're probably going to be sharing dynamic content.
This is done as follows, though you should really know this by now:
Code:
String sharedString = "Hey, we are sharing!";
Step 5 - The extras:
You have to also give the Intent its extra information. For this example, we'll be setting two types of extras: a subject and the body.
This way, there is flexibility. If the user chooses to share the text using an email application, the subject will also be used. If they don't, it won't be used.
This is done by adding the following lines to your sharing method:
Code:
shareIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "This is the subject");
shareIntent.putExtra(android.content.Intent.EXTRA_TEXT, sharedString);
Step 5 - The Chooser:
Whenever you share something, you see the Dialog pop up for you to select the app you want to use in your sharing the content. This is the next and last step in this guide, and is basically just starting the Intent with a special parameter.
Not every type of media can be shared to every app. When you share certain content, Android looks at what apps have declared themselves candidates for that MIME type.
So, if you are not seeing certain apps appear, check whether the app can work with that MIME type!
Start the Intent like this:
Code:
startActivity(Intent.createChooser(shareIntent, "Share via"));
Of course, the title to the chooser doesn't have to be "Share via". It can be any other text or variable (keep this in mind for apps that have translations!).
Facebook doesn't do this right! The facebook app doesn't do sharing right, so it will probably not show up in the list of apps that you might see when following the tutorial. To counteract this, target the app using the specific API.
Have fun sharing, and thanks for reading!
P.S.: Images can be added, should anyone want me to do so.

I also found this for the ActionBar very interesting: http://developer.android.com/reference/android/support/v7/widget/ShareActionProvider.html

nikwen said:
I also found this for the ActionBar very interesting: http://developer.android.com/reference/android/support/v7/widget/ShareActionProvider.html
Click to expand...
Click to collapse
True, the ShareActionProvider is quite nice but has one really big downside: You have to update it with the Intent BEFORE the user clicks the item, and there is no workaround. So if you want to generate an image when the user clicks share, you cannot use the ShareActionProvider.
And thanks for the guide OP!

SimplicityApks said:
True, the ShareActionProvider is quite nice but has one really big downside: You have to update it with the Intent BEFORE the user clicks the item, and there is no workaround. So if you want to generate an image when the user clicks share, you cannot use the ShareActionProvider.
And thanks for the guide OP!
Click to expand...
Click to collapse
Wouldn't it be possible to extend the class? Maybe it could be achieved that way.

nikwen said:
Wouldn't it be possible to extend the class? Maybe it could be achieved that way.
Click to expand...
Click to collapse
Could work, but I have no idea what methods to override... I need to have a closer look at this.

Way to store Preferences

Hey Guys,
I am creating a app to rename other apps via xposed and the main code is written. Now I simply want to make a interface where you can define a app to rename and then enter a new name. For the beginning I thought about a Activity where you enter the Package Name and the desired name. Later on I want to use a list view to show all apps, from where you can choose one to rename(Like App Settings etc.). To show the renamed apps I want to use a ListView. Now I am stuck with a problem: My xposed code works with an array to check and rename. The list view can be used with an array or an arraylist, but I need a way to store the preferences(which are stored in a array).
Do you have a good idea or a sample how to realise this? And does somebody know a nice App List type of thing(I googled, but the project there aren't usable with my kind of approach.)

GalaxyInABox said:
Hey Guys,
I am creating a app to rename other apps via xposed and the main code is written. Now I simply want to make a interface where you can define a app to rename and then enter a new name. For the beginning I thought about a Activity where you enter the Package Name and the desired name. Later on I want to use a list view to show all apps, from where you can choose one to rename(Like App Settings etc.). To show the renamed apps I want to use a ListView. Now I am stuck with a problem: My xposed code works with an array to check and rename. The list view can be used with an array or an arraylist, but I need a way to store the preferences(which are stored in a array).
Do you have a good idea or a sample how to realise this? And does somebody know a nice App List type of thing(I googled, but the project there aren't usable with my kind of approach.)
Click to expand...
Click to collapse
Ah the data storage problem... I think we all came across this at least once . I suppose you read this guide on the different options available? Well there are actually three options: SharedPreferences, text or csv file and SQL.
The first one would need some work around and is probably the slowest. You would save a separate string directly into the SharedPreferences (maybe in a new file to avoid collisions?) with the array name and its index somehow in the key. That's just two methods of coding but not the nicest way to do it.
The text or csv file however is the more common way, here you'd save your array in one line of the file, each item separated with a ; or some other char. Needs a bit more coding and also the WRITE_EXTERNAL_STORAGE permission on preKitKat if I remember correctly.
The third one is the nicest and most modular one. Because it makes use of SQL it needs quite a bit of knowledge and some coding (but less than the text file).
I guess for simple things that you want to do it is better to stay away from SQL for now unless you know how to use it and use the SharedPreferences.
Edit: take a look at the answers to this question, they give you the code as well... And you can use StringSets in ICS and above if the order of your list doesn't matter !

I'd say go down the SQLite DB way, chances are that if you plan on expanding your coding knowledge and want to keep creating apps you'll be needing to learn this in the future anyway so why delay?
Google AndroidHive and look at their SQL tutorial - I used it when learning and found it very informative
Sent from my HTCSensation using Tapatalk

Thank you very much! As coming from windows, first of all I thought about SQL as well, but it seems oversized for the set of data i want to store. I also took a look at the stackoverflow thread you linked. It looks easy to implement, but the need to use an external class file made me look for another way. I found this one, which works pretty well for me, as I look forward to interchange the method of saving the data with a better one using the SharedPreferences(which actually should be really easy with my code).
Maybe you can tell me yet another thing: Is there a way of declaring an object(like the ArrayList) to make it accessible from every class except from giving every class(activity) it's own "load the preferences" and "save the preferences" code block or sending intents all over the place? This would make saving much easier and allow me to update the preferences during runtime and without a reboot
Edit: This was my answer to.SimplicityApks ^^ I'll take a closer look at SQL now, since you, Jonny, told me that it' nevertheless necessary.

GalaxyInABox said:
Thank you very much! As coming from windows, first of all I thought about SQL as well, but it seems oversized for the set of data i want to store. I also took a look at the stackoverflow thread you linked. It looks easy to implement, but the need to use an external class file made me look for another way. I found this one, which works pretty well for me, as I look forward to interchange the method of saving the data with a better one using the SharedPreferences(which actually should be really easy with my code).
Maybe you can tell me yet another thing: Is there a way of declaring an object(like the ArrayList) to make it accessible from every class except from giving every class(activity) it's own "load the preferences" and "save the preferences" code block or sending intents all over the place? This would make saving much easier and allow me to update the preferences during runtime and without a reboot
Edit: This was my answer to.SimplicityApks ^^ I'll take a closer look at SQL now, since you, Jonny, told me that it' nevertheless necessary.
Click to expand...
Click to collapse
Welcome
You mean you want to make your ArrayList, which is an instance variable in the activity, accessible to every other class within your package without having an instance of your activity at hands? Well the basic solution would be to make the ArrayList static. But that is not recommended because it won't be created and garbage collected at the same time as your activity and also it's not a nice way .
If you had an instance of the activity it would be just using a public getter for it, but without I'd put your ArrayList into a separate class following the Singleton pattern. That way you have only one global instance which contains the ArrayList.

Thanks again for your reply! I changed my mind about the ArrayList and created a method, where everything is stored in the SharedPreferences and the ArrayList's only purpose is the use with the ListView and Adapter. This way I don't have to write the ArrayList to the SharedPreferences and changes will be much easier to control. Although I had to implement another type of save/load method to interact with the class thats being loaded by xposed. That was needed because of the restriction that you can only load SharedPreferences with a context, which my class doesn't have. It's an inconvenient way, but it works