Android SharedPreferences Example Code.docx

Android SharedPreferences Example Code.docx

《Android SharedPreferences Example Code.docx》由会员分享，可在线阅读，更多相关《Android SharedPreferences Example Code.docx（36页珍藏版）》请在冰豆网上搜索。

AndroidSharedPreferencesExampleCode

AndroidSharedPreferencesExampleCode（SaveUserData）

Simple AndroidSharedPreferencesExamplewithCodeDescription

HerewewilldiscussaboutAndroidSharedPreferencesexamplewithsourcecodeanddescription.ThatmeanswewilllearnabouthowtostorepersistentuserdatainourownAndroidapplicationandgetitbackwhenrequired.Alsowewilllearnhowtoadd,edit,retrieve（fetch）,load,store,deleteandupdatedatainAndroidSharedPreferences.Androidprovidesdifferentoptionstosavepersistentapplicationdata.Itiscompletelyyourchoicestowhichoptionyouwanttouseforyourapplication.Androidprovidesbelowdifferentdatastorageoptions.

SharedPreferences

Storeyourapplication’sprivateprimitivedata（workingaskey-valuepairs）.

YoucanuseSharedPreferencestosaveanyprimitivedataofyourapplicationlike:

boolean,float,int,long,andstringetc.Thisdatawillpersistacrossusersessions（evenifyourapplicationisclosedorforciblekilledbyAndroidOS）.

SQLiteDatabases

Storeyourapplication’sstructureddatainyourapplication’sprivatedatabase.Itwillstoreintheapplication’scontext.Ihavealreadywrittenaverynicearticleabouthowtosaveapplication’sdatainyourownAndroidSQLitedatabase.Clickheretoreadthisarticle.

NetworkConnection

Storeyourapplication’sdataonthewebwithyourownnetworkserver.Sothatotheruserscanaccessitwhenrequired.

InternalStorage

Storeyourapplicationsprivatedataonthephonememory（devicememory）

ExternalStorage

Storeyourapplication’sdataonthesharedexternalstorage,sothatotherapplicationcanbeaccessitifrequired.

NowitisenoughforsomebasicideaaboutdatastoringinAndroid.Let’scometoourmainfocuse.g. “AndroidSharedPreferencesexamplewithsourcecodedescription”

TomakethisAndroidsharedpreferenceexampleverysimple,wewillusedifferentAndroidprimitivedatatypeslike:

boolean,float,int,long,andstringetc andstoresomeuserdataintoAndroidSharedPreference. Thenwewillretrieve（fetch）thosestoreddatafromAndroidSharedPreferences.

Note:

Android SharedPreferencesusesonlyKey-Valuepairforstoringdata,thatmeans,whenwewillstoredatatoAndroidSharedPreferences,wewilluseauniquekeyandsomecorrospondingdatawiththatkey.

SimpleStepsfor AndroidSharedPreferencesUse

Step1:

Createanew SharedPreferencesfileinyourAndroidapplication.Wewillopenitifitisalreadyexist.WewillusethefunctiongetSharedPreferences（） functionfromtheinbuilt Androidclass.

Step2:

 Forgettingdatafromthe AndroidSharedPreferencesfile,wewillusefunctionslike getString（）,getInt（）etc.

Step3:

 Forstoringthedata,weneedtousetheAndroidEditorClassSharedPreferences.Editor.Thenwewill storedataintothe AndroidSharedPreferencesfileusingfunctions putString（）,putInt（）etc.thencommitthewholedatausingcommit（）function.

AndroidSharedPreferences Initialization

AndroidSharedPreferencescanbefetchusingthefunction getSharedPreferences（）. Thisfunctionneedacontext（yourActivitycontext）.souseyourActivitycontextifyouwillcallthisfromyouractivityclass.IfyoucallthisfromanonActivityclasslikeAndroidservices,thenfirststorethecontextanduseitfor getSharedPreferences（）.Don’tworrywewilldiscusscompletedetailsinbelowexample.thisisonlyforthecodesnippet.FinallyweneedanAndroideditorclasstosavethechangesintheAndroidSharedPreferences.Belowisthecodesnippet.

Firstimportthebelowpackageintoyourjavafile,whereyouwanttousesharedpreference.

1

importandroid.content.SharedPreferences;

SharedPreferencespref=getApplicationContext（）.getSharedPreferences（"MyPref",0）;//0-forprivatemode

//herethefirstparameterisnameofyourpreffilewhichwillholdyourdata.youcangiveanyname.

//Noteherethe2ndparameter0isthedefaultparameterforprivateaccess.

Editoreditor=pref.edit（）;//usedforsavedata

StoringDatainto AndroidSharedPreferences

Aftertheaboveinitializationcode,weneedtofollowthebelowcodesnippetforstoringdifferenttypesofdataintoAndroidSharedPreferences.

editor.putBoolean（"key_name1",true）;//Storingbooleanvalue-trueorfalse

editor.putString（"key_name2","string-value"）;//Storingstringvalue

editor.putInt（"key_name3","intvalue"）;//Storingintegervalue

editor.putFloat（"key_name4","floatvalue"）;//Storingfloatvalue

editor.putLong（"key_name5","longvalue"）;//Storinglongvalue

mit（）;//commitchangesintosharedpreferencesfile.

Note:

 Intheabovecodesnippet,tomakethecodebuildablepleasechange ”floatvalue”,“longvalue”totherealfloatandlongvalues.

FetchingDatafrom AndroidSharedPreferences

Datacanbefetchfromsavedpreferencesbycalling getString（） （Forstring）,getInt（）（forInt） methodetc.Notethat:

thesemethodsshouldbecalledusingSharedPreferencesnotusingEditor.Belowisthecodesnippet.

1

SharedPreferencespref=getApplicationContext（）.getSharedPreferences（"MyPref",0）;//0-forprivatemode

//gettingvaluesfromstoredpreferences

//Ifanyvalueisnotpresentinthepreferencesfile,thenthesecondparameterwillbethedefaultvalue-//Inthiscasenull

pref.getString（"key_name1",""）;//gettingString

pref.getInt（"key_name2",""）;//gettingInteger

pref.getFloat（"key_name3",null）;//gettingFloat

pref.getLong（"key_name4",null）;//gettingLong

pref.getBoolean（"key_name5",true）;//gettingboolean

 DeletingDatafrom AndroidSharedPreferences

IfyouwanttodeletesomespecificdatafromAndroidsharedpreferences,thenwecancallthefunction remove（“key_name”） todeletethatparticularvalue.Ifyouwanttodeleteallthedata,call clear（）function.

editor.remove（"key_name1"）;//willdeletethekeynamedkey_name1

editor.remove（"key_name2"）;//willdeletekeynamedkey_name2

mit（）;//commitabovechanges

Ifyouwanttoclear（delete）alldataatatimethenyoucanusethebelowcodesnippet.

editor.clear（）;//clearalldata.

mit（）;//commitchanges

 CreateProject:

 AndroidSharedPreferencesExample

NowcomingtotheAndroidSharedPreferencesExample.YoucanusethebelowexampletolearnaboutAndroidSharedPreferences.Wewillgetsomeinputdata（wehaveused3fields:

Name,EmployeeIDandAge）fromuser.Thenwewillsaveitintothesharedpreferencesfile,AfterthatwewillretrievethosevaluesfromtheandroidSharedPreferencesfile.Tomaketheexampleverysimple,wewilluse2buttons（Store andLoad）forthispurpose.AlsoihaveimplementedaSimple SharedPrefManagerClass.whichwillperformallAndroidSharedPreferencesoperationsforyou.Youcanuseandeditthisjavafile（SharedPrefManager Class）asperyourrequirement.Onlywhatyouneedtodois:

replacethepackagename‘packagecom.techblogon.sharedpreferenceexample;‘toyourapplication’spackagename.

1.Createaprojectwithprojectname:

 SharedPreferenceExample

2.FillApplicationName:

 SharedPreferenceExample

3.FillPackageNameas:

 packagecom.techblogon.sharedpreferenceexample;

4.IhaveusedSDKversion Android4.0.3 andEclipseVersion Indigo.Butyoucanuseanyversion.

5.Addbelowxmlfile（activity_main.xml）into yourproject’s res/layout folder.oryoucancopythexmlfilecontents.

Thisthedefaultxmlfileintheproject.hereweused3EditTextfieldtogetuserdatatostoreintothesharedpreferencesfile.Alsoadded2buttons（StoreandLoad）tomaketheoperationsimple.

android="

    xmlns:

tools="

    android:

layout_width="match_parent"

    android:

layout_height="match_parent"

    android:

orientation="vertical"

    tools:

context=".MainActivity">

      android:

id="@+id/textView"

      android:

layout_width="match_parent"

      android:

layout_height="wrap_content"

      android:

gravity="center_horizontal"

      android:

textStyle="bold"

      android:

layout_marginTop="10dp"

      android:

hint="SharedPreferenceExample"

      android:

ems="10">

        android:

id="@+id/editTextEnterName"

        android:

layout_width="fill_parent"

        android:

layout_height="wrap_content"

        android:

layout_marginTop="10dp"

        android:

maxLength="30"

        android:

hint="EnterYourName">

        android:

id="@+id/editTextEnterEid"

        android:

layout_width="fill_parent"

        android:

layout_height="wrap_content"

        android:

layout_marginTop="10dp"

        android:

maxLength="8"

        android:

inputType="number"

        android:

hint="EnterYourEmployeeID">

        android:

id="@+id/editTextEnterAge"

        android:

layout_width="fill_parent"

        android:

layout_marginTop="10dp"

        android:

inputType="number"

        android:

maxLength="2"

        android:

layout_height="wrap_content"

        android:

hint="EnterYourAge">

android="

    xmlns:

tools="

    android:

layout_width="match_parent"

    android:

layout_height="match_parent"

    android:

orientation="horizontal"

    android:

layout_marginTop="10dp"

    android:

gravity="center_horizontal">

        android:

id="@+id/buttonStore"

        android:

layout_height="wrap_content"

        android:

layout_width="wrap_content"

        android:

onClick="onClickStore"

        android:

text="Store"/>

        android:

id="@+id/buttonLoad"

        android:

layout_height="wrap_content"

        android:

layout_