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Address Book App

Define styles

res/values/address_book_styles.xml<item name="android:background">@drawable/textview_border</item>

Specify a background for a TextView– res/drawable/textview_border.xml– The textview_border is defined as a shape

element

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Create menu resources res/menu

– Define the MenuItems

The menu will be inflated by Activity’s MenuInflater

getMenuInflater().inflate(R.menu.addressbook_menu, menu);

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Extend ListActivity

A ListActivity’s default GUI consists of a

ListView (we do not need to define a separate

layout)– Specify the format that’s applied to each list item shown

in the ListView (contact_list_item.xml)

Create an Activity extends from ListActivitylv = getListView(); //get the built-in ListView

lv.setOnItemClickListener(oicl);

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ListView

ListView is a subclass of AdapterView, a

GUI component is bound to a data source via

an Adapter.

We use CursorAdapter to display the results

of a database query in the ListView.

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CursorAdapter SimpleCursorAdapter is a subclass of CursorAdapter that’s

designed to mapping Cursor columns directly to TextView or

ImageView

To create a SimpleCursonAdapter, you must first define arrays

containing the column names to map to GUI components

(contact_list_item.xml) and the resource IDs (R.id.contactTV)

of the GUI components that will display the data from the named columns.

String[] columns = {"name"};

int[] components = {R.id.contactTV};

contactAdapter = new SimpleCursorAdapter(this,

R.layout.contact_list_item, null, columns, components, 0);

lv.setAdapter(contactAdapter);

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CursorAdapter

SimpleCursorAdapter requires 6 arguments:

– Context in which the ListView is running

– Resource ID of the layout

– The Cursor that provides access to the data

– String array containing the column names to display

– int array containing the corresponding GUI resource

ID

– Flag

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AsyncTask

Perform action in one thread and receive the results in GUI thread

Three parameters:– Type of the parameter for doInBackground method,

which is performed in separate thread– Type of the parameter for onProgressUpdate method,

which is executed in the GUI thread and is used to receive intermediate updates of the specified type from a long-running task

– Type of the parameter for onPostExecute method, which is executed in the GUI thread and enables the Activity to use the AsyncTask’s results.

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AsyncTask example

GetContactTask extends AsyncTask<Object, Object, Cursor> private DatabaseConnector dbc;

protected Cursor doInBackground(Object... params) {dbc = new DatabaseConnector(AddressBook.this);dbc.open();return dbc.getAllContacts();}

protected void onPostExecute(Cursor result) {contactAdapter.changeCursor(result);dbc.close();super.onPostExecute(result);}

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OnResume

Get the complete list of contacts from the

database and make CursorAdpater works– (new GetContactTask()).execute((Object[ ])

null);

– execute do not receive any argument in this case

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OnStop

CursorAdpater Cursor is not needed

contactAdapter.changeCursor(null);

//adapter now has no cursor

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SQLite Database

DatabaseConnector– Database names must be unique within a

specific app but need not be unique across apps.

– A SQLiteDatabase object provides read/write access to a SQLite database

DatabaseOpenHelper extends SQLiteOpenHelper is used to manage creating, opening and upgrading databases

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DatabaseOpenHelper

Extends from SQLiteOpenHelper– Helps apps create databases and manage version

changes Constructor requires 4 arguments

– Context– Database name– CursorFactory = null indicates use default

SQLite CursorFactory– Database version number

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DatabaseOpenHelper

OnCreate– Create the “contacts” table contains an integer

primary key field (_id) that us auto-incremented, and 5 other text fields

– String cmd = "create table contacts " +"(" +– "_id integer primary key autoincrement, " +– "name text, " + "email text, " + – "phone text, " + "street text, " + – "city text " + ")";– db.execSQL(cmd); //execute the query

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Database Operations open close insertContacts

– ContentValue: key-value pairs– insert(db name, nullColumnHack, data)

updateContact– db.update("contacts", cv, "_id=?", new

String[]{id+""}); deleteContact(long id)

– db.delete("contacts", "_id=?", new String[]{id+””});

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Query method database.query(7 arguments)

– Database name– A String array of the column names to return– A SQL WHERE clause– A argument for WHERE clause– A SQL GROUP BY clause– A SQL HAVING clause– A SQL ORDER BY clause

getAllContacts– db.query("contacts", columns, null, null,

null, null, null); getOneContact(long id)

– db.query("contacts", columns, "_id=?", new String[]{id+””}, null, null, null);

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ViewContact LoadContactTask extends AsyncTask<Long,

Object, Cursor> doInBaground

– Open database– getOneContact(params[0])

onPostExecute– result.moveToFirst(); //move to the first item– nameTV.setText(result.getString(0));– phoneTV.setText(result.getString(1));– emailTV.setText(result.getString(2));– streetTV.setText(result.getString(3));– cityTV.setText(result.getString(4));– result.close();– dbc.close();

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DeleteContact Show alert dialog DeleteAsync extends AsyncTask<Long,

Object, Object> doInBaground

– Open database– deleteContact(params[0])

onPostExecute– finish(); //return to the AddressBook Activity

1. Dismiss any dialogs the activity was managing.

2. Close any cursors the activity was managing.

3. Close any open search dialog

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EditContact SaveContactTask extends

AsyncTask<Object, Object, Object>

doInBaground– Open database– updateContact

onPostExecute– finish()

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AddContact SaveContactTask extends

AsyncTask<Object, Object, Object> doInBaground

– Open database– insertContact

onPostExecute– finish()

Show alert dialog if name field is null

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