Andorid Storage Options

Transcription

1 CPET 565 Mobile Computing Systems CPET/ITC 499 Mobile Computing File Storage, Shared Preferences, and SQLite Database Reference Android Programming Concepts, by Trish Cornez and Richard Cornez, pubslihed by Jones & Barlett Learning, pp Paul I-Hai Lin, Professor Spring 2017 A Specialty Course Purdue University M.S. Technology Graduate Program Dept. of Computer, Electrical and Information Technology Purdue University Fort Wayne Campus 1 Andorid Storage Options Storage Options, nce/preference.html Shared Preferences: store private primitive data in key-value pairs Internal Storage: store private data on the device memory External Storage: store data on the shared external storage SQLIte Database: store structured data in a private database Network Connection: store data on the web system with your network server 2 1

2 Storing Data Shared Preferences Topics of Discussion File Storage Internal & External Storage Android Database and SQLite SQliteOpenHelper Adapters and AdapterViews 3 Storing App Data Applications often store information about a user s preferences in order to provide a more sophisticated level of personalization and responsiveness A user can log into and out of an application and have it remember them when the application is relaunched Users expect to choose settings according to their personal needs, such as specific background sounds and images, and have them automatically persist across user sessions 4 2

3 Storing App Data Advanced applications are frequently data-driven and require the management of a larger volume of data Databases and files can be used by an application to store structured data or information that will be made available to other applications 5 Storing App Data Choosing the manner in which data is stored depends upon the specific needs of the application, such as the amount of data that needs to be stored and whether the data will be kept private The Android platform allows data files to be saved on the device s internal memory and on an external storage media Files that are saved within the device s internal storage memory tend to be small, as opposed to external storage, which typically holds larger volume files 6 3

4 Shared Preferences Shared Preferences refers to the storage of a limited set of primitive data used to make persistent changes in an Android application A simple way to read and write key-value pairs of data Used to store a user s personal settings and a small amount of application session data SharedPreference information is backed up in XML files in internal storage Proprietary and inaccessible to outside applications 7 Shared Preferences Allows preference data values to automatically persist throughout sessions, regardless of how they end This includes exit of an application, shutdown of the device, or system crash 8 4

5 Shared Preferences: Key-value pair data A key-value pair is a data representation model that uses a set of key identifiers along with associated data values Model is frequently used in hash tables and configuration files Provides access to a data value or object by specifying its associated key SharedPreferences API provides a set of methods for reading and writing key-value pairs to files Shared preferences supports the String data type and Java primitive data types, such as int, float, long, and boolean 9 Shared Preferences APIs Saving Key-Value Sets, SharedPreferences API, SharedPreferences.html Preference, nce/preference.html PreferenceManager, nce/preferencemanager.html android.preference, nce/package-summary.html 10 5

6 File Storage: Internal and External 11 Topics of Discussion 12 6

7 Summary Q/A? 13 7