Android and SQLite

7/23/2019 Android and SQLite

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Week 6

TableLayout and SQLite


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Objectives

TableLayout, TableRow

Introduction to SQLite

SQLite Java classes in Android

SQLiteOen!eler SQLite"atabase

#ontent$alues

#ursor

SQLite "atabase Tutorial Add%Select%&date%"elete


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TABLE LAYOUT


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TableLayout and TableRow

'urose o( TableLayout is to or)ani*e &I ele+ents in a

table (or+at ac- row in a TableRow is a TableRow instance

TableRow is divided into cells, a cell contains a sin)lec-ild view

.u+ber o( colu+ns is dictated by t-e row wit- +ostcolu+ns

Widt- o( a colu+n is de/ned by t-e widest cell in t-at

colu+n

#olu+ns +ay be set as s-rinkable or stretc-able 0orbot-1 so t-ey c-an)e in si*e relative to t-e arent

TableLayout

A sin)le cell +ay be con/)ured to san +ultile colu+ns


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T-e 2&I


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T-e !ierarc-ical Tree o( t-e2&I


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SQLITE


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Introduction

T-e use o( database is an essentialasect o( +ost alications

Ran)in) (ro+ alications entirely datadriven, to t-ose si+ly need to stores+all a+ounts o( data

'ersistent data stora)e is +orei+ortant takin) into transient li(ecycle

o( an Android activity

Android rovides SQLite bounded wit-Android OS, rovides to (acilitate

ersistent stora)e


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W-at is SQLite3

SQLite is an e+bedded, R"45S

5ost R"45S are standalone server rocesses runindeendently 0e), 5s SQL, Oracle, 5ySQL, etc1

SQLite is re(erred to as e+bedded because it isrovided in t-e (or+ o( a library t-at is linked intoalications .o standalone "4 server runnin) in t-e back)round

All "4 oerations are -andled internally wit-in t-ealication t-rou)- calls to (unctions o( SQLite Lib

SQLite is written in #, Android S"7 rovides Javabased 8wraer9 around t-e "4 Inter(aceT-is consists o( a set o( classes to create and +ana)e "4


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Tryin) SQLite on an A$"

Android also rovides interactiveenviron+ent (or issuin) SQL co++ands(ro+ wit-in an adb s-ell sessionconnected to a runnin) Android A$"

Once an A$" is runnin), use Ter+inal toconnect to t-e e+ulator usin): adb eshell

SQLite databases are actually stored in adatabase /les on t-e /le syste+ o( t-eAndroid device


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SQLite "4 at-

4y de(ault, t-e /le syste+ at- (or t-e"4 /le is

), in an a wit- acka)e co+e;+le5y"4A

/data/data/com.example.MyDBApp/databases/mydatabase.db

/data/data//databases/.db


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ANDROID SQLITE JAVACLASSES


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#ursor

'rovided to access to t-e results o( a database

irst01: +oves to /rst row in t-e result

+oveToLast01: +oves to t-e last row in t-e result

+oveTo.e;t01: +oves to t-e ne;t row in t-e result

+ove01: +oves by a seci/ed o?set (ro+ current osition

)et@Tye01 B returns value o( seci/ed @Tye


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SQLite"atabase

It rovides t-e ri+ary inter(ace between t-e

alication code and underlyin) SQLitedatabasesTo create%delete databases

To er(or+ SQL based oerations on databases

So+e key +et-ods o( t-is class are: insert01: inserts new row into database table

delete01: deletes rows (ro+ a database table


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SQLiteOen!eler

"esi)ned to +ake it easier to create and udate

databases It +ust be subclassed wit-in t-e code o( t-e

alication seekin) database access

>ollowin) call back +et-ods +ust be i+le+ented on#reate01

#alled w-en database is created (or t-e /rst ti+e

It=s assed as ar)u+ent an SQLite"atabase object newlycreated

T-is is ideal location to initiali*e "4 like creatin) table andinsertin) initial rows

on&)rade01 #alled w-en a code contains +ore recent "4 version

Tyically -aen w-en a is udated on t-e device


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SQLiteOen!eler

In addition to t-e +andatory callback +et-ods

0listed reviously1, t-ere are so+e +ore +et-ods onOen01: called w-en "4 is oened

T-e constructor (or t-e subclass +ust also bei+le+ented

5ust call t-e suer class, assin) t-rou)- t-e alicationconte;t, t-e na+e o( t-e "4 and t-e "4 version

.otable +et-ods o( SQLiteOen!eler class: )etWritable"atabase01: oen or creates a "4 (or readin)

and writin) Returns a re(erence to t-e "4 )etReadable"atabase01: creates or oens a "4 (or

readin) only Returns a re(erence to t-e "4

close01: closes t-e database


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#ontent$alues

#ontent$alues is a convenience classt-at allows key%value airs to bedeclared

#onsistin) o( table colu+n identi/ersand t-e values to be stored in eac-colu+n

T-is class is o( articular use w-en

insertin) or udatin) entries in adatabase table


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SQLITE DATABASETUTORIAL


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About t-e "4 e;a+le

T-is roject is a si+le data entry andretrieval desi)ned to add,


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T-e classes

4esides t-e Activity class we will need

A database -andler A subclass o( SQLiteOen!eler

'rovides an abstract layer between t-e "4and activity

A database +odel class to reresent t-e'roduct


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#reate a roduct class


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Select aroriate +in S"7


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Add a 4lank Activity


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Inut Activity In(or+ation


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T-e "ata !andler


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on#reate and on&)rade+et-ods


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Add%Load !andler 5et-od


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"elete 'roduct !andler 5et-od


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&date 'roduct !andler5et-od


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5ain Activity 2&I


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5ain Activity Java #ode


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Add Activity 2&I &sin)TableLayout

dd i i d


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Add Activity Java #ode

- dd


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Test t-e Add >eature

L d A i i 2&I


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Load Activity 2&I

L t ( i l li t it


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Layout (or sin)le list ite+

L d A ti it J # d


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Load Activity Java #ode

T t T- L d > t


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Test T-e Load >eature

" l t %& d t 2&I


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"elete%&date 2&I

" l t & d t A ti it J


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"elete &date Activity Java

" l t & d t A ti it J


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"elete &date Activity Java

T t T- " l t > t


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Test T-e "elete >eature

& d t A ti it 2&I


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&date Activity 2&I

& d t A ti it J


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&date Activity Java

Test &date Acti it


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Test &date Activity

Su++aries


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Su++aries

TableLayout, TableRow

Introduction to SQLite

SQLite Java classes in Android SQLiteOen!eler

SQLite"atabase

#ontent$alues

#ursor

SQLite "atabase Tutorial Add%Select%&date%"elete

Android and SQLite

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