Android -- SQLite (add, delete, modify, query) Operation

Five classes are required: 1. entity class: Person. java2. abstract class: SQLOperate. java (encapsulates Database Operations) 3. helper class: DBOpenHelper. java (inherit from SQLiteOpenHelper) 4. implementation class: SQLOperateImpl. java (implements the abstract class SQLOperate. java) 5. test class: Test. java (inheriting AndroidTestCase) 1. person. java [html] package com. mrzhu. sqltite; public class Person {private int _ id; private String name; public int getId () {return _ id;} public void setId (int _ id) {this. _ id = _ id;} public String getName () {retu Rn name;} public void setName (String name) {this. name = name ;}@ Override public String toString () {return "Person [id =" + _ id + ", name =" + name + "]";} public Person () {super ();} public Person (int _ id, String name) {super (); this. _ id = _ id; this. name = name ;}} 2. SQLOperate. java [html] package com. mrzhu. sqltite; import java. util. list;/*** add, delete, modify, and query * @ author ZLQ **/public interface SQLOpe Rate {public void add (Person p); public void delete (int id); public void updata (Person p); public List <Person> find (); public Person findById (int id);} 3. DBOpenHelper. java [html] package com. mrzhu. sqltite; import android. content. context; import android. database. sqlite. SQLiteDatabase; import android. database. sqlite. SQLiteOpenHelper;/*** helper class ** @ author ZLQ **/public class DBOpneHelper extends S QLiteOpenHelper {private static final int VERSION = 1; // The private static final String DB_NAME = "people. db "; // database name public static final String STUDENT_TABLE =" student "; // table name public static final String _ ID =" _ id "; // public static final String NAME = "name"; // NAME of the column in the table // statement for creating a database, STUDENT_TABLE, _ ID, add a space before and after NAME: private static final String CREATE_TABLE = "create table" + STUDENT_TABLE + "(" + _ I D + "Integer primary key autoincrement," + NAME + "text)"; public DBOpneHelper (Context context) {super (context, DB_NAME, null, VERSION );} // call @ Override public void onCreate (SQLiteDatabase db) {db.exe cSQL (CREATE_TABLE );} // called during version upgrade @ Override public void onUpgrade (SQLiteDatabase db, int oldVersion, int newVersion) {}} 4. SQLOperateImpl. java [html] package com. mrzhu. sqltite; import Java. util. arrayList; import java. util. list; import android. content. contentValues; import android. content. context; import android. database. cursor; import android. database. sqlite. SQLiteDatabase; public class SQLOperateImpl implements SQLOperate {private DBOpneHelper dbOpenHelper; public partition (Context context) {dbOpenHelper = new DBOpneHelper (context);}/*** added, insert data into the database using insert */public v Oid add (Person p) {SQLiteDatabase db = dbOpenHelper. getWritableDatabase (); ContentValues values = new ContentValues (); values. put (DBOpneHelper. _ ID, p. getId (); values. put (DBOpneHelper. NAME, p. getName (); db. insert (DBOpneHelper. STUDENT_TABLE, null, values);}/*** delete, delete data by id */public void delete (int id) {SQLiteDatabase db = dbOpenHelper. getWritableDatabase (); db. delete (DBOpneHelper. STUDENT_TABL E, DBOpneHelper. _ ID + "=? ", New String [] {String. valueOf (id)});}/*** modify the data of the specified id */public void updata (Person p) {SQLiteDatabase db = dbOpenHelper. getWritableDatabase (); ContentValues values = new ContentValues (); values. put (DBOpneHelper. _ ID, p. getId (); values. put (DBOpneHelper. NAME, p. getName (); db. update (DBOpneHelper. STUDENT_TABLE, values, DBOpneHelper. _ ID + "=? ", New String [] {String. valueOf (p. getId ()});}/*** query all data in the table */public List <Person> find () {List <Person> persons = null; SQLiteDatabase db = dbOpenHelper. getReadableDatabase (); Cursor cursor = db. query (DBOpneHelper. STUDENT_TABLE, null, null); if (cursor! = Null) {persons = new ArrayList <Person> (); while (cursor. moveToNext () {Person person = new Person (); int _ id = cursor. getInt (cursor. getColumnIndex (DBOpneHelper. _ ID); String name = cursor. getString (cursor. getColumnIndex (DBOpneHelper. NAME); person. setId (_ id); person. setName (name); persons. add (person) ;}} return persons;}/*** query data of the specified id */public Person findById (int id) {SQLiteDatabase db = dbO PenHelper. getReadableDatabase (); Cursor cursor = db. query (DBOpneHelper. STUDENT_TABLE, null, DBOpneHelper. _ ID + "=? ", New String [] {String. valueOf (id)}, null); Person person = null; if (cursor! = Null & cursor. moveToFirst () {person = new Person (); int _ id = cursor. getInt (cursor. getColumnIndex (DBOpneHelper. _ ID); String name = cursor. getString (cursor. getColumnIndex (DBOpneHelper. NAME); person. setId (_ id); person. setName (name) ;}return person ;}} 5. test. java in AndroidManifest. <application> </application> in xml (targetPackage is the package name of the current project) <instrumentationandroid: targetPackage = "com. mrzhu. sqltite "android: name =" android. test. </InstrumentationTestRunner "> </instrumentation> in <application> </application>, add <uses-library android: name =" android. test. runner "/> [html] package com. mrzhu. sqltite; import java. util. list; import android. test. androidTestCase; import android. util. log; public class Test extends AndroidTestCase {public void testAdd () throws Exception {SQLOperateImpl test = new SQLOperateImpl (getContext (); Person person = new Person (2, "Peter "); test. add (person);} public void testDelete () throws Exception {SQLOperateImpl test = new SQLOperateImpl (getContext (); test. delete (1);} public void testUpdata () throws Exception {SQLOperateImpl test = new SQLOperateImpl (getContext (); Person person = new Person (1, "Tom"); test. updata (person);} public void testFind () throws Exception {SQLOperateImpl test = new SQLOperateImpl (getContext (); List <Person> persons = test. find (); for (Person person: persons) {Log. I ("System. out ", person. toString () ;}} public void testFindById () throws Exception {SQLOperateImpl test = new SQLOperateImpl (getContext (); Person person = test. findById (2); Log. I ("System. out ", person. toString ());}}