Download android sqlite example

The comment text will be generated later in the activity by a small random generator. We use here a ListActivity for displaying the data.

List; import java. Random; import android. ListActivity; import android. Bundle; import android. View; import android. Running the apps Install your application and use the Add and Delete button.

Restart your application to validate that the data is still there. A SQLite database is private to the application which creates it. If you want to share data with other applications you can use a content provider. A content provider allows applications to access data. In most cases this data is stored in an SQlite database. While a content provider can be used within an application to access data, its is typically used to share data with other application.

As application data is by default private, a content provider is a convenient to share you data with other application based on a structured interface. A content provider must be declared in the AndroidManifest.

Accessing a content provider The access to a content provider is done via an URI. Tip As it is required to know the URIs of an content providersto access it, it is good practice to provide public constants for the URIs to document them to other developers. Many Android datasources, e. Own ContentProvider To create your own ContentProvideryou have to define a class which extends android.

You also declare your ContentProviderin the AndroidManifest. This entry must specify the android:authoritiesattribute which allows to identify the ContentProvider. This authority is the basis for the URI to access data and must be unique. In case you do not support certain methods its good practice to throw an UnsupportedOperationException.

The query method must return a Cursor object. Security and ContentProvider Until Android version 4. As of Android 4. Tip It is good practice to always set the android:exportedparameter to ensure correct behavior across Android versions.

Thread Safety If you work directly with databases and have multiple writers from different threads you may run into concurrency issues. The ContentProvidercan be accessed from several programs at the same time, therefore you must implement the access thread-safe.

The easiest way is to use the keyword synchronizedin front of all methods of the ContentProvider, so that only one thread can access these methods at the same time. This permits an instance of the provider to be created in each client process, eliminating the need to perform interprocess communication IPC. Tutorial: Using ContentProvider 6. Overview The following example will use an existing ContentProviderfrom the People application. Create contacts on your emulator For this example we need a few maintained contacts.

Select the home menu and then the People entry to create contacts. The app will ask you if you want to login. Either login or select "Not now". Press ""Create a new contact". You can create local contacts. Finish adding your first contact. As a result you should have a few new contacts in your application.

Rename the ID of the existing TextViewto contactview. Delete the default text. The resulting layout file should look like the following.

Open the AndroidManifest. On that tab click the Add button, and select the Uses Permission. From the drop-down list select the android. Change the coding of the activity. Activity; import android. Uri; import android. ContactsContract; import android. Typically you would display such data in a ListView.

Purpose of the Loader class The Loaderclass allow you to load data asynchronously. They can monitor the source of the data and deliver new results when the content changes. They also persist data between configuration changes. If the result is retrieved by the Loaderafter the object has been disconnected from its parent activity or fragment , it can cache the data.

Loaders have been introduced in Android 3. They are available in the activity and the Fragment class. Using the Loader class You can use the abstract AsyncTaskLoaderclass as the basis for your own Loader implementations. The creation of a Loader is done via the getLoaderManager. The third parameter of initLoader is the class which is called once the initialization has been started callback class. Typically the activity is used as the callback class. The first parameter is a unique ID which can be used by the callback class to identify that Loader later.

The second parameter is a bundle which can be given to the callback class for more information. The Loaderis not directly created by the getLoaderManager. Once the Loaderhas finished reading data asynchronously, the onLoadFinished method of the callback class is called. Here you can update your user interface. It is good practice that an activity which uses a Loader implements the LoaderManager. This Loader performs the database query in a background thread so that the application is not blocked.

The CursorLoaderclass is the replacement for Activity-managed cursors which are deprecated now. If the Cursorbecomes invalid, the onLoaderReset method is called on the callback class. Cursors and Loaders One of the challenges with accessing databases is that this access is slow. The other challenge is that the application needs to consider the life-cycle of the components correctly, e.

To manage the life-cycle you could use the managedQuery method in activities prior to Android 3. May 16, at am. May 11, at pm. LJB says:. January 7, at am. Dody says:. January 24, at am. Prasanta says:.

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May 25, at am. June 30, at am. Flutter — Sqlite Database Example. In the Mobile devices, there are several ways to store persistent data. This code …. Mp Android Chart Library is developed by PhilJay and available on Github for every android developer who wish to create simple Graph chart inside their android applications. This library allow us to create beautiful charts to show our data into well settled format inside android apps. If the database is stored on the SDCard you can browse the data, change records and query the data.

The application accepts a student's roll number, name and marks and adds these details to a student table. The SQLiteDatabase class from the android. In the above code, the openOrCreateDatabase function is used to open the StudentDB database if it exists or create a new one if it does not exist. The first parameter of this function specifies the name of the database to be opened or created. The second parameter, Context.