2. Android database SQLite sqliteopenhelper

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The source code has been shared in the resource.

Http://download.csdn.net/detail/ta893115871/4440305

 

The interface is as follows:

There is a problem: Why can't the menu icon be set? Now the SDK version 4.0.4 is used, and sdk2.1 is used previously.

First, the property Android: icon = "@ drawable/Add" cannot be displayed in iem in the. xml file.

The second is my setion (R. drawable. Add) in the Java file; No.

Which of the following heroes knows? Thank you very much for leaving me some comments.

 

Sqliteopenhelperdemo. Java

Package COM. example. sqliteopenhelperdemo; import android. OS. bundle; import android. app. activity; import android. database. cursor; import android. database. SQLite. sqlitecursor; import android. view. keyevent; import android. view. menu; import android. view. menuitem; import android. view. view; import android. widget. adapterview; import android. widget. adapterview. onitemclicklistener; import android. widget. adapterview. on Itemselectedlistener; import android. widget. edittext; import android. widget. listview; import android. support. v4.widget. simplecursoradapter; public class sqliteopenhelperdemo extends activity {private edittext medittext; private listview mlistview; private simplecursoradapter adapter; private mydatabase database; private cursor mcursor; private int _ id; // The field value of the current cursor @ suppresswarnings ("deprecation") @ over Ridepublic void oncreate (bundle savedinstancestate) {super. oncreate (savedinstancestate); setcontentview (R. layout. activity_sqlite_open_helper_demo); medittext = (edittext) This. findviewbyid (R. id. edit_id); mlistview = (listview) This. findviewbyid (R. id. listview_id); mlistview. setonitemclicklistener (clicklistener); mlistview. setonitemselectedlistener (selectedlistener); // create a reference database for the sqliteopenhelper object = new Mydatabase (this);/* obtain the information in the database */mcursor = database. query ();/* New simplecursoradapter and input mycursor. The data field is displayed as _ id, todo_text */adapter = new simplecursoradapter (this, R. layout. list, mcursor, new string [] {mydatabase. field_id, mydatabase. field_text}, new int [] {R. id. itemid_id, R. id. itemcon_id,}); mlistview. setadapter (adapter) ;}@ overridepublic Boolean oncreateoptionsmenu (menu) {getmenuinflater (). infl Ate (R. menu. activity_sqlite_open_helper_demo, menu); Return true;} public Boolean onmenuitemselected (INT featureid, menuitem item) {Switch (item. getitemid () {case R. id. menu_add: This. add (); break; case R. id. menu_modfi: This. moD (); break; case R. id. menu_delete: This. delete (); break; default: break;} return false;}; // listview Click Event Processing onitemclicklistener clicklistener = new onitemclicklistener () {public void oni Temclick (adapterview <?> Arg0, view arg1, int arg2, long arg3) {// todo auto-generated method stubmcursor. movetoposition (arg2); _ id = mcursor. getint (mcursor. getcolumnindex (mydatabase. field_id); medittext. settext (mcursor. getstring (mcursor. getcolumnindex (mydatabase. field_text) ;}}; // listen to the event handling the mouse wheel processing onitemselectedlistener selectedlistener = new onitemselectedlistener () {public void onitemselected (adapterview <?> Arg0, view arg1, int arg2, long arg3) {// todo auto-generated method stub_id = mcursor. getint (mcursor. getcolumnindex (mydatabase. field_id); sqlitecursor c = (sqlitecursor) arg0.getselecteditem (); medittext. settext (C. getstring (C. getcolumnindex (mydatabase. field_text);} public void onnothingselected (adapterview <?> Arg0) {// todo auto-generated method stub}; // update listviewpublic void myupdateshow () {/* re-query */mcursor. requery (); // inform the adapter that the adapter has changed. notifydatasetchanged (); medittext. settext (""); _ id = 0;} // Add public void add () {string STR = medittext. gettext (). tostring (); If (Str. equalsignorecase ("") {return;}/* add data to the database */database. addmethod (STR); myupdateshow () ;}// modify public void Mod () {string STR = medittext. gettext (). tostring (); If (Str. equalsignorecase ("") {return;} // modify the database. modmethod (_ id, STR); myupdateshow () ;}// Delete public void Delete () {If (_ id = 0) {return;} database. deletemethod (_ id); myupdateshow () ;}@ overridepublic Boolean onkeydown (INT keycode, keyevent event) {// todo auto-generated method stubif (keycode = keyevent. keycode_back) {// closes the database and exits the program database. close (); this. finish ();} return Super. onkeydown (keycode, event );}}

Mydatabase. Java

Package COM. example. sqliteopenhelperdemo; import android. content. contentvalues; import android. content. context; import android. database. cursor; import android. database. SQLite. sqlitedatabase; import android. database. SQLite. sqliteopenhelper; import android. util. log; public class mydatabase extends sqliteopenhelper {Private Static final string database_name = "demo_db"; // database name Private Static final int databa Seversion = 1; // version Private Static final string table_name = "demo_table"; // The table name public static final string field_id = "_ id "; // It Must Be _ idpublic static final string field_text = "demo_text"; private sqlitedatabase dB; // database Private Static final string tag = "mydatabase"; Public mydatabase (context) {super (context, database_name, null, databaseversion); // todo auto-generated constructor stubdb = This. get Writabledatabase (); // open or create a database (created at the first time) to obtain the sqlitedatabase object. To read and write data} @ overridepublic void oncreate (sqlitedatabase dB) {// todo auto-generated method stub/* Create Table */log. I (TAG, "oncreate ()"); string SQL = "CREATE TABLE" + table_name + "(" + field_id + "integer primary key autoincrement, "+" "+ field_text +" text) "mongodb.exe csql (SQL);} // update Database @ overridepublic void onupgrade (sqlitedatabase dB, int ol Dversion, int newversion) {// todo auto-generated method stublog. I (TAG, "onupgrade ()"); // Delete the sqlstring SQL = "Drop table if exits" + table_namemongodb.exe csql (SQL); oncreate (db );} // close the Database @ overridepublic synchronized void close () {// todo auto-generated method stublog. I (TAG, "close ()"); dB. close (); super. close () ;}@ overridepublic void onopen (sqlitedatabase db1) {// todo auto-generated method stublog. I (Tag, "onopen ()"); super. onopen (db1);} // Add public long addmethod (string Str) {/* Add the new value to contentvalues */contentvalues CV = new contentvalues (); cv. put (field_text, STR); // key-Value Pair long row = dB. insert (table_name, null, CV); log. I (TAG, "addmethod ROW =" + row); Return row;} // Delete public void deletemethod (INT ID) {string [] whereargs = {integer. tostring (ID)}; int rowsaffected = dB. delete (table_name, field_id + "=? ", Whereargs); log. I (TAG, "deletemethod () rowsaffected =" + rowsaffected);} // modify public void modmethod (INT ID, string Str) {contentvalues values = new contentvalues (); values. put (field_text, STR); string [] whereargs = {integer. tostring (ID)}; int rowsaffected = dB. update (table_name, values, field_id + "=? ", Whereargs); log. I (TAG, "modmethod () rowsaffected =" + rowsaffected);} // query all data and return the cursor object public cursor query () {// ASC is in ascending order. DESC is in descending order (ASC by default). Return dB. query (table_name, null, field_id + "ASC ");}}

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For other layout XML files, see Resource:

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