Data storage--SP Storage

I. Storage type: sharedpreferences storage

Two. Sharedpreferences Storage

1. Features

① stores single data, such as numeric, String, Boolean

② file:/date/date/package name/shared_prefs/xxx.xml: <map><string name= "Key" >value</string></map>

③ stored as key-value pairs

④ can be set to not be manipulated by other apps

2.API

(1) sharedpreferences

① Get Instance context.getsharedpreferences ():

1) name store file name; 2) mode operation: Mode_private cannot be accessed by other application, overwrite mode, mode_append cannot be accessed by other application, append mode;

② Startup editor: Edit (): Back to Editor

③ read value:1) getString (key,defvalue default) 2) GetAll () returns a map collection of all key-value pairs

(2) Editor

① Storage data: 1) putstring (key,value) 2) Putlong (key,value) 3) Putint 4) putfloat 5) Putboolean 6) Putstringset

② Commit Storage

③clear () Clear

④remove (String key) removes the key value pair of the instruction key

1<?xml version= "1.0" encoding= "Utf-8"?>2<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"3Xmlns:tools= "Http://schemas.android.com/tools"4Android:layout_width= "Match_parent"5android:layout_height= "Match_parent"6android:paddingbottom= "@dimen/activity_vertical_margin"7android:paddingleft= "@dimen/activity_horizontal_margin"8android:paddingright= "@dimen/activity_horizontal_margin"9android:paddingtop= "@dimen/activity_vertical_margin"Tentools:context= "Com.hanqi.testapp3.MainActivity" Oneandroid:orientation= "Vertical" > A  -<TextView -Android:layout_width= "Wrap_content" theandroid:layout_height= "Wrap_content" -android:text= "Hello world!"/> -      -<Button +Android:layout_width= "Match_parent" -android:layout_height= "Wrap_content" +android:text= "SP Storage" Aandroid:onclick= "Bt_onclick"/> at  -<Button -Android:layout_width= "Match_parent" -android:layout_height= "Wrap_content" -android:text= "SP read" -android:onclick= "Bt1_onclick"/> in  -</LinearLayout>

. XML

1  Packagecom.hanqi.testapp3;2 3 Importandroid.content.SharedPreferences;4 ImportAndroid.os.Bundle;5 Importandroid.support.v7.app.AppCompatActivity;6 ImportAndroid.view.View;7 ImportAndroid.widget.Toast;8 9  Public classMainactivityextendsappcompatactivity {Ten  One @Override A     protected voidonCreate (Bundle savedinstancestate) { -         Super. OnCreate (savedinstancestate); - Setcontentview (r.layout.activity_main); the     } -  -      Public voidBt_onclick (View v) -     { +         //1. Get Sharedpreferences Object -Sharedpreferences sharedpreferences=getsharedpreferences ("abc"), mode_append); +  A         //2. Get the editor atSharedpreferences.editor editor=Sharedpreferences.edit (); -  -         //3. Adding Data Using editor - //editor.putstring ("B", "xxxxxx"); - //Editor.putlong ("Long", 123456); -  inEditor.remove ("a"); -  to  +         //4. Submit a Save - editor.commit (); the  *Toast.maketext (mainactivity. This, "Save data successfully", Toast.length_short). Show (); $     }Panax Notoginseng  -     //Read the      Public voidBt1_onclick (View v) +     { ASharedpreferences sp=getsharedpreferences ("abc"), mode_private); the  +String str=sp.getstring ("AB", "Default value")); -  $Toast.maketext (mainactivity. This, "key=b" + "value=" +str, toast.length_short). Show (); $     } -}

. Java

Data storage--SP Storage