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2  data/data-storage.html#pref data/data-storage.html#pref  ples/63.html ples/63.html  Hello Android, chapter 9

3  Shared Preferences Shared Preferences ◦ Store private primitive data in key-value pairs.  Internal Storage Internal Storage ◦ Store private data on the device memory.  External Storage External Storage ◦ Store public data on the shared external storage.  SQLite Databases SQLite Databases ◦ Store structured data in a private database.  Network Connection Network Connection ◦ Store data on the web with your own network server

4 Store private primitive data in key-value pairs

5  How to save and retrieve data?  Using SharePrference class ◦ persistent key-value pairs ◦ only primitive data types.  booleans, floats, ints, longs, and strings.  This data will persist across user sessions ◦ even if your application is killed

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7  getSharedPreferences() getSharedPreferences() ◦ Use this if you need multiple preferences files identified by name, which you specify with the first parameter.  getPreferences() getPreferences() ◦ Use this if you need only one preferences file for your Activity. Because this will be the only preferences file for your Activity, you don't supply a name

8  Write ◦ Call edit() to get a SharedPreferences.Editor.edit()SharedPreferences.Editor ◦ Add values with methods such as putBoolean() and putString().putBoolean() putString() ◦ Commit the new values with commit()commit()  Read ◦ use SharedPreferences methods such as getBoolean() and getString().SharedPreferences getBoolean()getString()

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10 Store private data on the device memory

11  You can save files directly on the device's internal storage.  By default, files saved to the internal storage are private to your application and other applications cannot access them (nor can the user).  When the user uninstalls your application, these files are removed.

12  Call openFileOutput() with the name of the file and the operating mode. This returns a FileOutputStream.openFileOutput()FileOutputStream  Write to the file with write().write()  Close the stream with close().close()

13  Call openFileInput() and pass it the name of the file to read. This returns a FileInputStream.openFileInput()FileInputStream  Read bytes from the file with read().read()  Then close the stream with close().close()

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17  XML resources can mean resources in general that are defined in XML, ◦ layout files, styles, arrays, res/xml XML files.  In this section we will be dealing with res/xml XML files.

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23 SQLite Databases

24  A tiny yet powerful database engine created by Dr. Richard Hipp in  It is arguably the most widely deployed SQL database engine in the world.  Besides Android, SQLite can be found in the Apple iPhone, Symbian phones, Mozilla Firefox, Skype, PHP, Adobe AIR, Mac OS X, Solaris, and many other places.

25  It’s free. ◦ The authors have placed it in the public domain and don’t charge for its use.  It’s small. ◦ The current version is about 150KB, well within the memory budget of an Android phone.  It requires no setup or administration. ◦ There is no server, no config file, and no need for a database administrator.

26  Android stores the file ◦ /data/data/packagename/databases  You can take that file, move it around, and even copy it to another system ◦ for example, from your phone to your workstation), and it will work fine.  You can use the adb command or the File Explorer view in Eclipse to view, move, or delete it. ◦ Window > Show View > Other... > Android > File Explorer)

27 Nothing here yet

28  Goal ◦ Save time stamps and string to a table ◦ Display it

29  Constants describing the database ◦ Constants interface  represent the database ◦ Using SQLiteOpenHelper  Driver ◦ Main program

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31 manages database creation and versions. All you need to do is provide a constructor and override two methods. DATABASE_VERSION is just a number we make up. If this were a real program, you would increase the version number whenever you had to make significant changes to the database design (for example, to add a new column).

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35 close the database inside the finally block. So even if an error occurs in the middle, the database will still be closed. Every time you run this program, you’ll get a new event. Running a Query

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42  Allows you to connect your model (data) to your view with just a few lines of code.  To demonstrate data binding, we’ll modify the Events example to use a ListView that is bound to the result of a database query.

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45 putting the ID, time, and title on one line with colons in between the fields. added a little padding and formatting to make it look nice.

46 need to change the layout for the activity itself in layout/main.xml


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