Android data storage with IO (i)

1.Sharedpreference Introduction

In order to save the parameters of the software, or some smaller data, we can use the Sharedpreference class that Android provides for me. He is a lightweight storage class, Ideal for saving software parameters using Sharedpreference to save data, behind which data is stored using an XML file
Files are stored in the/data/data/<-package name->/shared_prefs directory

Instance

<relativelayout xmlns:android= "Http://schemas.android.com/apk/res/android"      xmlns:tools= "Http://schemas.android.com/tools"  android:layout_width= "Match_parent"      android:layout_height= "Match_parent"  android:paddingleft= "@dimen/activity_horizontal_margin"      android:paddingright= "@dimen/activity_horizontal_margin"     android: paddingtop= "@dimen/activity_vertical_margin"     android:paddingbottom= "@dimen/activity_ Vertical_margin " tools:context=". Mainactivity ">   <button       android:id=" @+id/ Buttonwrite "       android:layout_width=" Wrap_content "        android:layout_height= "Wrap_content"        android: text= "Write Data"        android:layout_alignparenttop= "true"    &Nbsp;   android:layout_centerhorizontal= "true"  />    <edittext         android:id= "@+id/edit"          android:layout_width= "Fill_parent"         android:layout_ height= "Wrap_content"         android:layout_below= "@+id/buttonWrite"         android:layout_alignparentleft= "true"          android:layout_alignparentstart= "true"  />    <button         android:id= "@+id/buttonreade"          android:layout_width= "Wrap_content"         android: layout_height= "Wrap_content"         android:text= "read Data"          android:layout_below= "@+id/edit"         android:layout_alignleft = "@+id/buttonwrite"         android:layout_alignstart= "@+id/buttonWrite "        android:layout_margintop=" 73DP " />     <textview        android:id= "@+id/textview"          android:layout_width= "Wrap_content"          android:layout_height= "Wrap_content"         android:text= "Yu"         android:textsize= "20SP"          android:layout_alignparentbottom= "true"         android: Layout_centerhorizontal= "true"         android:layout_marginbottom= " 167DP " /></relaTivelayout> 

package xiaocool.net.sharedpreferencestest;import android.content.sharedpreferences;import  Android.support.v7.app.actionbaractivity;import android.os.bundle;import android.view.menu;import  android.view.MenuItem;import android.view.View;import android.widget.Button;import  Android.widget.edittext;import android.widget.textview;public class mainactivity extends  actionbaractivity {    //reading data according to key     private  sharedpreferences preferences;    //Writing Data     private  sharedpreferences.editor editor;    private button write,read;     private EditText editText;    private TextView textView;      @Override     protected void oncreate (bundle  Savedinstancestate)  {    &Nbsp;   super.oncreate (savedinstancestate);         Setcontentview (R.layout.activity_main);         write= (Button) This.findviewbyid (R.id.buttonwrite);         read= (Button) This.findviewbyid (R.id.buttonreade);         edittext= (EditText) This.findviewbyid (R.id.edit);         textview= (TextView) This.findviewbyid (R.id.textview);         preferences= Getsharedpreferences ("Xiaocool", mode_private);         editor= Preferences.edit ();         write.setonclicklistener (new  View.onclicklistener ()  {             @Override             public void&nbsP;onclick (VIEW V)  {                editor.putstring ("Name", Edittext.gettext (). toString ());                 editor.commit ();                 edittext.settext ("");             }        });       read.setonclicklistener (New view.onclicklistener ()  {            @Override            public void onclick (VIEW V)  {               string name=preferences.getstring ("name", null);           &Nbsp;   textview.settext (name);           }      &NBSP);    }     @Override      public boolean oncreateoptionsmenu (Menu menu)  {         // Inflate the menu; this adds items to the  action bar if it is present.         Getmenuinflater (). Inflate (R.menu.menu_main, menu);         return  true;    }     @Override     public  Boolean onoptionsitemselected (Menuitem item)  {        / / handle action bar item clicks here. the action bar will         // automatically handle clicks on the home/up button, so  long        // as you specify a parent  activity in androidmanifest.xml.        int id  = item.getitemid ();        //noinspection  simplifiableifstatement        if  (Id == R.id.action_ Settings)  {            return true;         }        return  super.onoptionsitemselected (item);     }}

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/5B/96/wKiom1UM1rjSBxeWAAEbo_7sXBM143.jpg "title=" Qq20150321102409.png "alt=" Wkiom1um1rjsbxewaaebo_7sxbm143.jpg "/>

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/5B/91/wKioL1UM1_nihuMHAAcGSxFq3-w259.jpg "title=" Qq20150321100908.png "alt=" Wkiol1um1_nihumhaacgsxfq3-w259.jpg "/>

accessing in other applications

public class readotherpreferences extends actionbaractivity {     @Override     protected void oncreate (bundle savedinstancestate)  {         super.oncreate (savedinstancestate);         setcontentview (R.layout.activity_main);         Context context =null;        try{             //get context       for other applications       context=createpackagecontext ("Xiaocool.net.sharedpreferencestest", context.context_ignore_security);        }catch  ( Packagemanager.namenotfoundexception e) {             e.printstacktrace ();                     }         //Use the context  of other programs to get the corresponding .sharedpreferences         sharedpreferences sharedpreferences=context.getsharedpreferences ("YU", context.mode_world_readable)         //Read Data          string name=sharedpreferences.getstring ("name", null);         toast.maketext (readotherpreferences.this,name,1). Show ();     }}

Android data storage with IO (i)