I have been trying to find a discussion on the best way to handle a common sqlite database which is shared by multiple Activities (or multiple Activities and Services). This is all in the same application.
It seems that if each Activity has:
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I am developing an app which requires me to write to an SQLiteDatabase in one activity and access it from another activity . I am facing a problem implementing this. Any suggestions/ideas as to how we can share the database across multiple activities?
View 2 Replies View RelatedCan two or more Android Activities open an sqlite3 database for write?
I have two Activities that need to insert data into the same sqlite database. When the second Activity calls SQLiteOpenHelper.getWriteableDatabase() an IllegalStateException is thrown with the message "SQLiteDatabase created and never closed".
I've been able to avoid the Exception by making my database object a singleton but I'm thinking there must be a better way.
I'm in the middle of writing myself an app and have run into a problem concerning the use of the same SQLite database within multiple activities.
I have one activity that is used to input and store data and multiple activities that need to then read that data. Within the first activity, it has no problem inputting the data into the database, but when I go to have the other activity read the data, it tells me the database is empty. Obviously I'm doing something wrong in my handling of this shared database.
Right now, I have a DataHelper class that handles everything. In each activity, I create a DataHelper object which then calls the openOrCreateDatabase() method. I then close the database upon exiting the activity. Obviously this isn't the right way to do it.
So, my questions is, what is the correct way to set up an SQLite database in an Android application and then access it in multiple activities?
I am creating an app which allows for many different Activities to be started from a TabActivity(up to ~25). Most of the activities require data from the sqlite database, so when onCreate is run, an AsyncTask creates an SQLiteOpenHelper object(which will open a readable/writable database), runs a query, data is retrieved, and everything is then closed.
I was just testing messing around to see if i could break something, so i added every Activityto the TabActivity's TabHost. I then started mashing each tab as quickly as possible.
I noticed that very quickly i began to see in the LogCat: Caused by: android.database.sqlite.SQLiteException: database is locked: BEGIN EXCLUSIVE; and the app proceeded to die.
Typically there will only be about 4-6 tabs(i can just limit the user anyway) for the TabHost. I haven't been able to break anything with a small amount of tabs to mash, but i am still worried that maybe i am accessing the database in a poor way.
How can i prevent my SQLiteDatabase objects to cause a lock?
If i create a ContentProvider will that eliminate the possibility of database locking?
Do you have any suggestions for changes I could make for accessing data from an SQLiteDatabase?
I ended up taking the approach of using the Application class and storing 1 SQLiteOpenHelper and trying my best to keep it synchronized. This seems to be working great - i put all my 25 activities in the TabHost and mashed away on them with no errors.
I am calling ((SQLiteDbApplication)getApplication()).setDbHelper(new DBHelper(this, Constants.DB_NAME, null, Constants.DB_VERSION_CODE)); method(shown below) in every onCreate() in my activities
Any further suggestions to this approach or to the changes i made using this Application class?
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I have a todo list type application that stores all of the note data in a sqlite3 database. Each activity in the application needs access to the database to edit different parts of the data in real time.
Currently, I have each activity open its own DBManager object (the helper class I created to manage the database). This is causing problems though and I would like a slightly more global access solution so I don't have to keep opening/closing/creating a database.
I'm considering several options, and would like to hear pros and cons of each as well as other suggestions.
Singleton style. Have a wrapper class that returns a reference to the only database manager so any activity that needs it can use it.
Static Manager. Have the manager class be entirely static members and have it open the database on load. Easily accessible by anyone that needs it (which is everyone).
Merger between 1 and 2. I could make a database manager class that initializes the member singleton instance of the database and all of the data manipulation methods were static. Then I wouldn't even need a reference to the singleton to access the database.
I'm new to Android programming, and I wanted to pull list options from a column of the SQLite database for the user to select. How would I go about doing this? Like, say the database table to be read is called countries, and the columns were ID, country, and capital. How would I let the user pick from the list of capitals and have the application return the information in that row?
View 1 Replies View RelatedAre there design guidelines to help decide if an application with multiple views should be designed with multiple activities or just one activity and control the back button itself.
I've tried both. My most complex applications using one activity per screen. However, now that I'm successfully written an app with just one activity and handling the back button myself, I don't see any compelling reason to use multiple activities. The one activity application is much simpler and more straightforward.
What advantages of multiple activities am I missing?
Can any one give me some code to close all the services and activities of my app so they dont reopen? i know in android you dont have to close your app but i want the app to exit if the terms of service are not accepted. at the moment im using android.os.Process.killProcess(android.os.Process.myPid()); in one of my activities but the launch activity automatically starts aggin, any way to prevent this?
View 9 Replies View RelatedI am presently working on services.I have read many articles related to services.But one thing I don't understand is if we want our application to run in background how can we implement services without using Activities.
View 2 Replies View RelatedI am working on a small android project where it is necessary to share some data amongst several activities and a service that runs in a separate process. I would just like to know what are my options in terms of sharing data? Application class? IPC? File-based? Broadcasts?
View 3 Replies View RelatedI'm working on an application using xml layouts.
I wish to know which is better:
1. Use few activities and change its contentview
2. Use an activity for each 'view' needed
If both works, in which case which option would be better?
I'm planning to develop and app that presents the users with several different screens (of different information).
Was wondering what would be the best way to implement this?
Is it better to have separate XML layouts and an activity to display and allow the user to interact with each screen of data?
OR would handling all of these in the same activity be more efficient (and dynamically load / unload each layout)?
I have some shared preferences (user_id, email) that I want to access from services and classes that are not subclassed from Activity. I have been trying to implement this today and keep hitting roadblocks. In particular, when I try to access getSharedPreferences, I get a null pointer exception. My code is posted below. My goal here is to allow read access the shared preferences to objects and (potentially) services that aren't going to be directly exposed to the user.
<snip> public class MyPrefs extends Service {
public static final String PREFS_NAME = "MyPrefs";
private int user_id;
private String user_email;
private String user_password;
private Editor editor = null;
private SharedPreferences settings = null;
public MyPrefs () {
settings = this.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
}
</snip>
this.getSharedPreferences line causes a null pointer exception.
Can a services exists as a stand alone with out any activities/ default. Is it possible to create services with out any activities associated with it as a stand alone inside a apk. (just a service).
View 2 Replies View RelatedI'm trying to deploy an application with an existing SQLite database.I've been reading though the examples that are posted but they are always missing some part of the class. I feel like I'm trying to bake muffins but no one told me to use baking powder.Can someone post a full database helper class for depoying an SQLite database on Android? Edit : Delete old code because it doesn't work.
View 2 Replies View RelatedI'm currently developing a Field-Service application that stores data in the local sqlite database on an android device. At some point, usually after completing the data collection rounds, the local sqlite db is to be synchronized to a remote sybase db on the server.Any suggestions as to how this could be achieved or engineered as a solution? Or even better, are there alternatives to synchronizing data in such an application?
View 1 Replies View RelatedI'm new to Android, I just finished the Notepad Tutorials, where we can create SQLite Databases to save notes. So I wanted to know if it was possible to "import" my own SQLite database (not created with my App but with a 3rd-party software) to my project, and if the answer is yes, where should I save my SQLite databse and how can I have access to it.
View 9 Replies View RelatedI'm doing a application that will use a database with serialized object. The objects will be already serialized and the user will just display things. On a PC I would just make an XML but with android I'm not sure. Can I make an XML and "unpack" it when the user launch the application for the first time or should I do something else?
View 3 Replies View RelatedI put my database field in "assets" folder. And use the code from this blog to copy the database to "/data/data/my_packname/databases/", (This copy code i run it in the onCreate() method when i run this app) then use select * from ... to get data. But it gives me the exception: no such table. Someone told me that if i am attempting to copy the file in SQLiteOpenHelper's onCreate(), it's too late. So the copy file code can not copy the complete file. So i need to use adb or ddms to pull the database first? So, Anyone can teach me how to use my own databse?
View 3 Replies View RelatedI have an app which will start multiple separate services which perform an action and then exit. I don't want them all to run at the same time (because this may bog down the OS).
I have the code for finding the services and starting the services, but does anyone know how I can make sure one service has completed before the next starts.
Due to what the app does it will have to start multiple services and the actions the services perform have no GUI and may take tens of seconds or minutes (hence why I'm using a service so the user isn't just shown a blank screen every time the next service starts).
I have a class like class My data{ String name; int data; Location[] locality.
View 8 Replies View RelatedI am new to android and I have a problem in creating a database.
public class database extends ListActivity {
/** Called when the activity is first created. */
private final String MY_DATABASE_NAME = "myCoolUserDB.db";
private final String MY_DATABASE_TABLE = "t_Users";
Context c;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ArrayList<String> results = new ArrayList<String>();
setContentView(R.layout.main);
SQLiteDatabase mydb=null;
try
{
mydb.openOrCreateDatabase(MY_DATABASE_NAME, null);
} catch(Exception e){}
}}
When I run this code it throws a run time exception.
How do I delete the sqlite database exists in my android? There is a db behind my android qro and delete the same
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public void delete(String id, String name, String phonenumber, String time, String message)
{
String[] args={id};
getWritableDatabase().delete("texts", "_ID=?", args);
}
It works fine, and deletes the specified row. However, I also want to implement it so that I can delete the most recent (earliest date) entry in the database, which should be at the top of the table. I know I can do this by altering the last 2 parameters of delete, but I cannot figure out what to change them to.
Is possible update the records from SQLite from my Android Application1 from other Application2 Android
View 4 Replies View RelatedIs there any UI can connect to SQLite database? I hope that I can read the data without writing code.is there any method can make it happened?
View 6 Replies View RelatedIs it really necessary to close an SQLite database that your activity has opened (database is in local memory or on SD card)? I would think it would be good practice, but I noticed that the Android samples such as the Notepad tutorial and SearchableDictionary sample do not do this. I've also seen sample code where the database is consistently opened, read from, and closed, but that would seem to add unnecessary overhead.
View 5 Replies View RelatedI successfully created the Database and inserted a row however I cannot Query it for some reason. My Droid crashes everytime.
CODE:...........
I get this exception
No such column: value: , while compiling: SELECT DISTINCT value FROM mainTable
I'm looking for a very simple ORM framework working on Android for sqlite. I've been testing activeAndroid but none of the example could ever build on Eclipse. By the way, how do guys implements a "many to many" relationship in sqlite for android ? How do you reflect the cascade regarding deletion of rows and guarantee the database integrity?
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