When to use a Content Provider

Question

I understand that Content Providers are made to allow publicly sharing data between applications. However, I'm wondering if anyone has thoughts about making a Content Provider to use just within your own app. Would there be any advantages to doing this? Any disadvantages?

In the past I've just implemented the SQliteOpenHelper to access data from my database, but I'm considering creating a Content Provider. I feel like the URI approach to requesting data is clear and concise. On the other hand, will using a Content Provider just for my application be redundant ( since within it I will have a SQliteOpenHelper class ) and more work than I need?

Wavemeter

I made a library to make content provider easy to write. Even easier than write plain SQLiteOpenHelper. github.com/coocood/VContentProvider – Ventilate

Answer 1

If you are not planning to share data, don't think about Content Providers. They are powerful but hard to write and it will be just silly to implement them if you are going to use them internally.

However, I'm wondering if anyone has thoughts about making a Content Provider to use just within your own app.

Of course... for instance, for an old TODO list app I wrote, I had to write a content provider to allow other apps retrieve and access the tasks states. It was part of the requirements, but more than that it made sense and made the app nicer.

Diversification

I agree with your justification, but I also think it's important (especially for the beginners) that once the Content Provider is implemented you gain a lot of benefits. For example, you can use the CursorLoader to perform asynchronous queries... you have access to a singleton instance (the ContentResolver) to perform queries, etc. Of course you could implement your own Loader to use for your SQLite database... of course you could implement access to a single database instance across the entire application... and of course a ContentProvider isn't required unless you wish to share – Proclaim

data with other apps. That said, there are many benefits that come with implementing your own Content Provider, so you shouldn't drop it from consideration just because your app doesn't share its data. – Proclaim

Yeah, you are completely right but I still think it does not worth the effort in most cases. I have done at least 12 different Android apps (published to the Play Store) and have never need a ContentProvider. In fact, the last app we were working on was initially made with a ContentProvider and we just deleted that since it is actually more a pain in the ass to use than it should (I even wrote a library to make it easier to implement basic ContentProviders: github.com/casidiablo/persistence but had never use it my self XD). – Diversification

@Diversification provides most practical advice. Even Android document states that we shouldn't use ContentProvider if we don't need to - "You don't need a provider to use databases or other types of persistent storage if the use is entirely within your own application and you don’t need any of the features listed above. Instead, you can use one of the storage systems described on the Saving App Data page.". Otherwise, we are just over engineering. – Prose

Summary: If you are not planning to share your data, you can avoid Content Provider but on other hand Content Provider makes your life easy if you want to change your app's database. e.g. from SQLite to MangoDB. – Vookles

@Diversification How safe is to use Content Provider, as my data is available for modification. Some unwanted app could take advantage of it. – Vookles

Answer 2

I would argue it is definitely a good idea to use a ContentProvider even if you don't intend to make it public.

It's good practice to provide the extra level of abstraction over your data to make it easier to change internally. What if you decide to change the underlying database structure at a later time? If you use a ContentProvider you can contain all the structural changes within it, where as if you don't use one, you are forced to change all areas of the code that are affected by the structural changes. Besides, it's nice to be able to re-use the same standard API for accessing data rather than littering your code with low-level access to the database.

Also, there is always the chance that you might want to expose your data in the future. If you don't use a ContentProvider up front, it will be much harder to retrofit it in at a later date.

Then, there's the other parts of the Android where ContentProvider's are required/recommended such as when using SyncAdapters and if you want an App Widget that involves data access for instance.

In summary, there is very little overhead involved in writing a ContentProvider up front (once you have learned the API which is a good idea anyway) so it makes sense to do so, even for private data.

Dramatization

I couldn't agree more. It forces you to abstract your data layer in a way that practically ensures a new developer won't be able to couple the UI with it. – Unhesitating

Immediately after learning Android, I started thinking the same way exactly for this reason. Even if not public, you can always benefit from the increased abstraction and the single point of implementation of your architectural decisions. I love ContentProviders. – Kura

I didn't get "What if you decide to change the underlying database structure at a later time? If you use a ContentProvider you can contain all the structural changes within it" part. Please help me with it? – Chipboard

You can make the content provider only available to your own application with this attribute: android:exported="false" – Bracketing

In my humble opinion, you can, and should handle your data in a completely abstracted way, without any need to implement ContentProvider. – Berne

As i was on my way implementing a contentprovider solution for my internal sqlite db (no interaction with other apps), i saw the remark on developer.android.com/guide/topics/providers/… which states You don't need a provider to use an SQLite database if the use is entirely within your own application. – Sympathize

Answer 3

Take a look at the MOTODEV Studio for Eclipse. It is a development environment that extends Eclipse. They have a tool where you can automatically generate a content provider for a database. If a content provider makes it easier to access your data and it doesn't have a significant impact on performance go ahead and use it. In most scenarios this will be the case.

Nimocks

Answer 4

In short,Content Providers helps in managing your data effectively. I would suggest to use them for the following reasons.

• It acts as an abstraction layer between your UI and database. You can implement data validation in ContentProviders to validate the data entered by the user. It also lets you to modify the structure of the database without touching the UI and other parts.
• They play along nicely with other android framework classes like SyncAdapter. For eg., you can automatically refresh a list, when a value in a database changes using ContentProviders along with CursorLoader. Without ContentProviders you have to implement a lot of functionalities like these on your own.
• We can safely expose our private data to other apps. Using ContentProviders will allow us to share our data easily and safely with other apps.

So even if you don't need any of these functionalities now, you might need them in future and its good to go the extra mile and implement them right now.

Plumley

Great answer. Single sentence description of ContentProviders and three separate reasons why we should use them. Sometimes the simple explanations are the best. +1 – Fissirostral

Answer 5

I agree ContentProviders are a little difficult to grasp but they are definitely helpful, even if you want to use them internally for you own app. The best thing about it is that you can customize the contentproviders for suitable URIs.

Here's a scenario where you may have 5 tables in your database, but you need to join a few of them in certain orders before using them. And make a content URI for each of these joins. You could then each use these URIs as a table :)

I suggest you go ahead with Content Provider, you'll be amazed to see how powerful it is.

Solemnize

Answer 6

In my view point, the content-provider comes with plenty of advantages leave alone just sharing data with other apps. If you need to synchronize with the server using a Sync-Adapter, use google cloud messaging, auto update the UI when the underlying data in the DB changes using Loaders, implement search, use widgets... then the content provider is for you.

I prefer you follow the guideline on because one day you may need to implement some of the above features attached to the content-provider

By the way, you can quickly build you database and CP in less than 5 minutes using content provider generator

Jeanmariejeanna

Answer 7

As said in documentation: Creating a Content provider

You don't need a provider to use an SQLite database if the use is entirely within your own application.

So why bother developing this overhead? You want easier and faster development, right? So one layer of abstraction (SQLiteOpenHelper descendent) is enough.

See Occam's Razor Do not make an entities without very good reason.

Overpower

Answer 8

Using a Content Provider can help in an additional level of abstraction - Putting it within your own application make add a significant development time to your project. However if you are using it to share data, application settings or configurations across multiple applications then the Content Provider is your choice.

Watch your security levels and I would recommend using SQLcipher to encrypt data-at-reset (DAR) if your Content Provider is writing to SQLite. (I've used a content provider in a few solutions and provided the ability to take a live "snap shot" of the operational values for debugging and testing.)

Workman

Answer 9

Do not use content provider if do not wish to share data with other apps. Use simple sqlitedatabase to perform database operations. Be careful while using content providers for storing confidential data because your confidential information may be accessed by other apps

Tilley

By default content providers are not exposed, and managing access restrictions to them is easy. Downvote for spreading misinformation. – Dialogize

@Dialogize You are (were) wrong. In fact until API Level 17 Content Providers were exposed. And to the time of the answer 25% of Android devices were affected from this behaviour and still 10% at the time of your comment. So, it is more the other way around: your comment is dangerous, as you state something to be secure which is/was not the fact. – Barocchio