Use of Android Learning note-sqlite

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Interface file Activity_main.xml

    <button         android:id= "@+id/ Createbutton "        android:layout_width=" Fill_parent "         android:layout_height= "Wrap_content"          android:layout_below= "@id/hello_world"         android:text = "Create database"/>    <button          android:id= "@+id/updatebutton"         android:layout_width= "fill _parent "        android:layout_height=" Wrap_content "         android:layout_below= "@id/createbutton"          android:text= "Update database"/>        <button     &Nbsp;    android:id= "@+id/insertbutton"          Android:layout_width= "Fill_parent"         android:layout_height= "Wrap_ Content "        android:layout_below=" @id/updatebutton "         android:text= "Insert database"/>         <button         android:id= "@+id/ Updaterecordbutton "        android:layout_width=" Fill_parent "         android:layout_height= "Wrap_content"          android:layout_below= "@id/insertbutton"          android:text= "Update record"/>        <button          aNdroid:id= "@+id/queryrecordbutton"         android:layout_width= "Fill_ Parent "        android:layout_height=" Wrap_content "         android:layout_below= "@id/updaterecordbutton"          android:text= "Query record"/>

datab Asehelper.java

package com.example.sqlite_01;import android.content.context;import  Android.database.sqlite.sqlitedatabase;import android.database.sqlite.sqlitedatabase.cursorfactory;import  android.database.sqlite.SQLiteOpenHelper;public class DatabaseHelper extends  Sqliteopenhelper{private static final int version = 1;public databasehelper (context context, string name, cursorfactory factory,int version)  {super ( context, name, factory, version);} Public databasehelper (context context, string name, int  version)  { This (context, name, null, version);} Public databasehelper (Context context, string name)  {this (context, name,  VERSION);} The first time the database is created, it is actually called @overridepublic void oncreate (SQLITEDATABASE DB) when the first time the Sqlitedatabase object is obtained.  {system.out.println ("Create a databASE ");d B.execsql (" Create table user (Id int, name varchar (20)) ");} @Overridepublic  void onupgrade (sqlitedatabase db, int oldversion, int  newversion)  {system.out.println ("Update a database");} /* * abd shell Enter the databases directory under the current app directory to see the database created  *  open the database sqlite3 test_db *   View the table in the current database and the statement that created the table  .schema */}

maina Ctivity.java

package com.example.sqlite_01;import android.support.v7.app.actionbaractivity;import  android.content.contentvalues;import android.database.cursor;import  Android.database.sqlite.sqlitedatabase;import android.os.bundle;import android.view.menu;import  android.view.menuitem;import android.view.view;import android.view.view.onclicklistener;import  android.widget.button;public class mainactivity extends actionbaractivity { private button createbutton = null;private button updatebutton = null; private button insertbutton = null;private button updaterecordbutton =  null;private Button queryRecordButton = null; @Overrideprotected  void  OnCreate (bundle savedinstancestate)  {super.oncreate (savedinstancestate); Setcontentview ( R.layout.activity_main);createbutton =  (Button)  findviewbyid (r.id.creAtebutton);updatebutton =  (Button)  findviewbyid (R.id.updatebutton);insertbutton =  ( button)  findviewbyid (R.id.insertbutton);updaterecordbutton =  (button)  findviewbyid ( R.id.updaterecordbutton);queryrecordbutton =  (Button)  findviewbyid (R.id.queryrecordbutton); Createbutton.setonclicklistener (New createlistener ()); Updatebutton.setonclicklistener (new  Updatelistener ()); Insertbutton.setonclicklistener (New insertlistener ()); Updaterecordbutton.setonclicklistener (New updaterecordlistener ()); Queryrecordbutton.setonclicklistener ( New querylistener ());} class createlistener implements onclicklistener{@Overridepublic  void onclick (View  V)  {databasehelper dbhelper = new databasehelper (MainActivity.this,  "Test_ DB "); Sqlitedatabase db = dbhelper.getreadabledatabase ();//execute this sentence before you create a database}}class updatelistener  implements onclicklistener{@OveRridepublic void onclick (VIEW V)  {DatabaseHelper dbHelper = new  Databasehelper (mainactivity.this,  "test_db",  2); Sqlitedatabase db = dbhelper.getreadabledatabase ();//execute this sentence before you create a database}}class insertlistener  implements onclicklistener{@Overridepublic  void onclick (view v)  {contentvalues  contentvalues = new contentvalues (); Contentvalues.put ("id",  1); ContentValues.put (" Name ", " Umgsai ");D Atabasehelper dbhelper = new databasehelper (MainActivity.this,   "test_db",  2); Sqlitedatabase db = dbhelper.getwritabledatabase ();d b.insert ("User", null,  contentvalues);}} class updaterecordlistener implements onclicklistener{@Overridepublic  void onclick ( VIEW V)  {databasehelper dbhelper = new databasehelper (MainActivity.this,  " test_db ",  2); Sqlitedatabase db =&nBsp;dbhelper.getwritabledatabase (); Contentvalues values = new contentvalues (); Values.put ("name",  "admin");d b.update (" User ", values, " ID = ? ",  new string[]{" 1 "});} class querylistener implements onclicklistener{@Overridepublic  void onclick (View  V)  {databasehelper dbhelper = new databasehelper (MainActivity.this,  "Test_ DB ",  2); Sqlitedatabase db = dbhelper.getreadabledatabase ();//db.query (table, columns,  Selection, selectionargs, groupby, having, orderby) Cursor cursor = db.query ("User",  new string[]{"id",  "name"},  "ID = ?",  new string[]{"1"},  null, null,  "id");while  (Cursor.movetonext ())  {String name =  Cursor.getstring (Cursor.getcolumnindex ("name")); System.out.println ("name>>>"  + name);}}}

You can view the database through the ADB shell command

>ABD Shell

>ls-l (view files and folders in the current directory)

>CD data (enter data directory)

>ls-l (view files and folders in the current directory )

>CD data (enter data directory)

>ls-l (view files and folders in the current directory )

>CD com.example.sqlite_01 (enter current project directory)

>ls-l (view files and folders in the current directory )

>CD databases (enter the databases directory)

>ls-l (You can now see the database file test_db)

>sqlite3 test_db (using SQLite to open the test_db database )

>.schema (view the table in the current database and the statement that created the table )

>select * from user; (Querying data from the user table)

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Use of Android Learning note-sqlite