Address Book App
1
Define styles
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res/values/address_book_styles.xml
<item
name="android:background">@drawable/textview_border
</item>
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Specify a background for a TextView
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2
res/drawable/textview_border.xml
The textview_border is defined as a shape
element
Create menu resources
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res/menu
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2
Define the MenuItems
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The menu will be inflated by Activity’s
MenuInflater
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getMenuInflater().inflate(R.menu.add
ressbook_menu, menu);
Extend ListActivity
A ListActivity’s default GUI consists of a
ListView (we do not need to define a separate
layout)
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Specify the format that’s applied to each list item shown
in the ListView (contact_list_item.xml)
Create an Activity extends from ListActivity
lv = getListView(); //get the built-in ListView
lv.setOnItemClickListener(oicl);
5
ListView
5
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ListView is a subclass of AdapterView, a
GUI component is bound to a data source via
an Adapter.
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We use CursorAdapter to display the results
of a database query in the ListView.
CursorAdapter
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SimpleCursorAdapter is a subclass of CursorAdapter that’s
designed to mapping Cursor columns directly to TextView or
ImageView
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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);
5
CursorAdapter
SimpleCursorAdapter requires 6 arguments:
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5
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Context in which the ListView is running
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Resource ID of the layout
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The Cursor that provides access to the data
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String array containing the column names to display
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int array containing the corresponding GUI resource
ID
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Flag
AsyncTask
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Perform action in one thread and receive the results in
GUI thread
Three parameters:
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6
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 longrunning 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.
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);}
6
OnResume
Get the complete list of contacts from the
database and make CursorAdpater works
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5
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(new GetContactTask()).execute((Object[ ])
null);
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execute do not receive any argument in this case
OnStop
5
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CursorAdpater Cursor is not needed
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contactAdapter.changeCursor(null);
//adapter now has no cursor
SQLite Database
DatabaseConnector
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7
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
DatabaseOpenHelper
Extends from SQLiteOpenHelper
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Constructor requires 4 arguments
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7
Helps apps create databases and manage version
changes
Context
Database name
CursorFactory = null indicates use default
SQLite CursorFactory
Database version number
DatabaseOpenHelper
OnCreate
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Create the “contacts” table contains an integer
primary key field (_id) that us auto-incremented,
and 5 other text fields
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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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7
Database Operations
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7
open
close
insertContacts
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ContentValue: key-value pairs
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insert(db name, nullColumnHack, data)
updateContact
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db.update("contacts", cv, "_id=?", new
String[]{id+""});
deleteContact(long id)
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db.delete("contacts", "_id=?", new
String[]{id+””});
Query method
database.query(7 arguments)
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getAllContacts
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db.query("contacts", columns, null, null,
null, null, null);
getOneContact(long id)
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7
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
db.query("contacts", columns, "_id=?", new
String[]{id+””}, null, null, null);
ViewContact
LoadContactTask extends AsyncTask<Long,
Object, Cursor>
doInBaground
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onPostExecute
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7
Open database
getOneContact(params[0])
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();
DeleteContact
Show alert dialog
DeleteAsync extends AsyncTask<Long,
Object, Object>
doInBaground
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Open database
deleteContact(params[0])
onPostExecute
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finish(); //return to the AddressBook Activity
1.
2.
3.
7
Dismiss any dialogs the activity was managing.
Close any cursors the activity was managing.
Close any open search dialog
EditContact
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SaveContactTask extends
AsyncTask<Object, Object, Object>
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doInBaground
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onPostExecute
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7
Open database
updateContact
finish()
AddContact
SaveContactTask extends
AsyncTask<Object, Object, Object>
doInBaground
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onPostExecute
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7
Open database
insertContact
finish()
Show alert dialog if name field is null