How to use ContentValues to operate the database
This article introduces the relevant knowledge of "how to use ContentValues to operate the database". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!
In main.xml:
Create a table operation class Mytab.java for creating a database
Package com.li.sqlite
Import android.content.ContentValues
Import android.database.sqlite.SQLiteDatabase
Public class Mytab {
Private static final String TABLENAME = "mytab"; / / indicates the name of the data table to be operated on
Private SQLiteDatabase db = null; / / database operation
Public Mytab (SQLiteDatabase db) {
This.db = db
}
Public void insert (String name,String birthday) {/ / add data to the table
ContentValues cv = new ContentValues ()
Cv.put ("name", name)
Cv.put ("birthday", birthday)
This.db.insert (TABLENAME, null, cv)
This.db.close ()
}
Public void update (int id, String name, String birthday) {/ / modify table data
ContentValues cv = new ContentValues ()
Cv.put ("name", name)
Cv.put ("birthday", birthday)
String whereCaluse = "id=?"
String whereArgs [] = new String [] {String.valueOf (id)}
This.db.update (TABLENAME, cv, whereCaluse, whereArgs)
This.db.close ()
}
Public void delete (int id) {/ / delete the data of the table
String whereCaluse = "id=?"
String whereArgs [] = new String [] {String.valueOf (id)}
This.db.delete (TABLENAME, whereCaluse, whereArgs)
This.db.close ()
}
}
In the MyDatabaseHelper.java class:
Package com.li.sqlite
/ / Auxiliary operation class of database
Import android.content.Context
Import android.database.sqlite.SQLiteDatabase
Import android.database.sqlite.SQLiteOpenHelper
Public class MyDatabaseHelper extends SQLiteOpenHelper {
Private static final String DATABASENAME = "liyewen.db"
Private static final int DATABASERVERSION = 1; / / set the version of the database
Private static final String TABLENAME = "mytab"
Public MyDatabaseHelper (Context context) {/ / users are definitely only concerned about Context
Super (context, DATABASENAME, null, DATABASERVERSION)
}
@ Override
Public void onCreate (SQLiteDatabase db) {/ / create datasheet
String sql = "CREATE TABLE" + TABLENAME + "("
+ "id INTEGER PRIMARY KEY," / / set to Integer in SQLite, PRIMARY KEY will automatically increase ID
+ "name VARCHAR (50) NOT NULL,"
+ "birthday DATE NOT NULL" + ")"
Db.execSQL (sql); / / execute SQL
System.out.println ("* create: onCreate ().")
}
@ Override
Public void onUpgrade (SQLiteDatabase db, int oldVersion, int newVersion) {
String sql = "DROP TABLE IF EXISTS" + TABLENAME
Db.execSQL (sql)
System.out.println ("* Update: onUpgrade ().")
This.onCreate (db)
}
}
In MySQLiteDemo.java:
Package com.li.sqlite
Import android.app.Activity
Import android.database.sqlite.SQLiteOpenHelper
Import android.os.Bundle
Import android.view.View
Import android.view.View.OnClickListener
Import android.widget.Button
Public class MySQLiteDemo extends Activity {
Private Button inserBut = null
Private Button updateBut = null
Private Button deleteBut = null
Private SQLiteOpenHelper helper = null
Private Mytab mtab = null
Private static int count = 0
@ Override
Public void onCreate (Bundle savedInstanceState) {
Super.onCreate (savedInstanceState)
Super.setContentView (R.layout.main)
This.inserBut = (Button) super.findViewById (R.id.insertBut)
This.updateBut = (Button) super.findViewById (R.id.updateBut)
This.deleteBut = (Button) super.findViewById (R.id.deleteBut)
This.helper = new MyDatabaseHelper (this)
This.inserBut.setOnClickListener (new InertOnClickListenerImpl ())
This.updateBut.setOnClickListener (new UpdateOnClickListenerImpl ())
This.deleteBut.setOnClickListener (new DeleteOnClickListenerImpl ())
}
Private class InertOnClickListenerImpl implements OnClickListener {
Public void onClick (View v) {
MySQLiteDemo.this.mtab = new Mytab (
MySQLiteDemo.this.helper.getWritableDatabase ()
MySQLiteDemo.this.mtab.insert ("liyewen" + count++, "1988-08-16")
}
}
Private class UpdateOnClickListenerImpl implements OnClickListener {
Public void onClick (View v) {
MySQLiteDemo.this.mtab = new Mytab (
MySQLiteDemo.this.helper.getWritableDatabase ()
MySQLiteDemo.this.mtab.update (72, "update", "1988-8-15")
}
}
Private class DeleteOnClickListenerImpl implements OnClickListener {
Public void onClick (View v) {
MySQLiteDemo.this.mtab = new Mytab (
MySQLiteDemo.this.helper.getWritableDatabase ()
MySQLiteDemo.this.mtab.delete (73)
}
}
}
This is the end of the content of "how to use ContentValues to operate the database". Thank you for your reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!
