"android 9" sqliteopenhelper class, add-and-revise operation
Last Update:2017-06-18
Source: Internet
Author: User
<span id="Label3"></p>Sqliteopenhelper class<p><p>The Sqliteopenhelper class is a tool class provided by Android for manipulating the SQLite database, which makes it easy to create databases, tables, and manage Database Versions.</p></p><p style="text-align: left" align="center"><p style="text-align: left" align="center"><strong>Common methods</strong></p></p><p><p>1, synchronized sqlitedatabase getreadabledatabase ();</p></p><p><p>Function: open the object of the database corresponding to the Sqlitedatabase class in a read-write manner</p></p><p><p>2, synchronized sqlitedatabase getwriteabledatabase ();</p></p><p><p>Function: Create or open the object of the library corresponding to the Sqlitedatabase class in a written way</p></p><p><p>3, abstract OnCreate (sqlitedatabase db);</p></p><p><p>Role: The first time you create a database Si cho method.</p></p><p><p>4, abstract Onupgrade (sqlitedatabase db,int oldversion,int newversion);</p></p><p><p>Role: database version update Si cho method.</p></p><p><p>5, synchronized void Close ();</p></p><p><p>Function: closes all open sqlitedatabase Objects.</p></p><p><p></p></p>add, delete, change Operation "definition mysqliteopenhelper"<pre><span style="color: #008080"><span style="color: #008080">1</span></span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">class</span></span>Mysqliteopenhelper<span style="color: #0000ff"><span style="color: #0000ff">extends</span></span><span style="color: #000000"><span style="color: #000000">sqliteopenhelper{</span></span><span style="color: #008080"><span style="color: #008080">2</span></span> <span style="color: #008000"><span style="color: #008000">/**</span></span><span style="color: #008000"><span style="color: #008000">overriding parent class construction methods</span></span><span style="color: #008000"><span style="color: #008000">*/</span></span><span style="color: #008080"><span style="color: #008080">3</span></span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span><span style="color: #000000"><span style="color: #000000">mysqliteopenhelper (context Context) {</span></span><span style="color: #008080"><span style="color: #008080">4</span></span> <span style="color: #008000"><span style="color: #008000">//</span></span><span style="color: #008000"><span style="color: #008000">Create the specified database: activity object, database file name, cursor factory, database version number</span></span><span style="color: #008080"><span style="color: #008080">5</span></span> <span style="color: #0000ff"><span style="color: #0000ff">Super</span></span>(context, "person.db",<span style="color: #0000ff"><span style="color: #0000ff">NULL</span></span>, 1<span style="color: #000000"><span style="color: #000000">);</span></span><span style="color: #008080"><span style="color: #008080">6</span></span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080">7</span></span> <span style="color: #008000"><span style="color: #008000">/**</span></span><span style="color: #008000"><span style="color: #008000">called only the first time the database is created, the database is used only in the calling</span></span><span style="color: #008080"><span style="color: #008080">8</span></span> <span style="color: #008000"><span style="color: #008000">Getwritabledatabase is really called when it's time</span> .</span><span style="color: #008000"><span style="color: #008000">*/</span></span><span style="color: #008080"><span style="color: #008080">9</span></span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span><span style="color: #000000"><span style="color: #000000">onCreate (sqlitedatabase Db) {</span></span><span style="color: #008080"><span style="color: #008080">Ten</span></span>Db.execsql ("create table if not exists person ("<span style="color: #008080"><span style="color: #008080"></span> one</span>+ "pid Integer PRIMARY key autoincrement,"<span style="color: #008080"><span style="color: #008080"></span> a</span>+ "name varchar", "+" phone varchar (12)); "<span style="color: #000000"><span style="color: #000000">);</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #008000"><span style="color: #008000">/**</span></span><span style="color: #008000"><span style="color: #008000">modified table structure, called when database version is updated</span></span><span style="color: #008000"><span style="color: #008000">*/</span></span><span style="color: #008080"><span style="color: #008080"></span> the</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span>Onupgrade (sqlitedatabase db,<span style="color: #0000ff"><span style="color: #0000ff">int</span></span>oldversion,<span style="color: #0000ff"><span style="color: #0000ff">int</span></span><span style="color: #000000"><span style="color: #000000">Newversion) {</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #000000"><span style="color: #000000"> } </span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #008000"><span style="color: #008000">/**</span></span><span style="color: #008000"><span style="color: #008000">inserting data into the database</span></span><span style="color: #008000"><span style="color: #008000">*/</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span><span style="color: #000000"><span style="color: #000000">Insert (String sql,string [] Args) {</span></span><span style="color: #008080"><span style="color: #008080"></span> +</span> <span style="color: #008000"><span style="color: #008000">//</span></span><span style="color: #008000"><span style="color: #008000">Create an object, open the database in write mode</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Sqlitedatabase db=<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">. Getwritabledatabase ();</span></span><span style="color: #008080"><span style="color: #008080"></span> +</span> <span style="color: #000000"><span style="color: #000000">Db.execsql (sql,args);</span></span><span style="color: #008080"><span style="color: #008080"></span> a</span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080"></span> at</span> <span style="color: #008000"><span style="color: #008000">/**</span></span><span style="color: #008000"><span style="color: #008000">Delete data from a database</span></span><span style="color: #008000"><span style="color: #008000">*/</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span><span style="color: #000000"><span style="color: #000000">Delete (String sql,string [] Args) {</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Sqlitedatabase db=<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">. Getwritabledatabase ();</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #000000"><span style="color: #000000">Db.execsql (sql,args);</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #008000"><span style="color: #008000">/**</span></span><span style="color: #008000"><span style="color: #008000">updating data in a database</span></span><span style="color: #008000"><span style="color: #008000">*/</span></span><span style="color: #008080"><span style="color: #008080"></span> in</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span><span style="color: #000000"><span style="color: #000000">update (String sql,string [] Args) {</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Sqlitedatabase db=<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">. Getwritabledatabase ();</span></span><span style="color: #008080"><span style="color: #008080"></span> to</span> <span style="color: #000000"><span style="color: #000000">Db.execsql (sql,args);</span></span><span style="color: #008080"><span style="color: #008080"></span> +</span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>}</pre><span class="cnblogs_code_collapse"><span class="cnblogs_code_collapse">Mysqliteopenhelper Class Code</span></span><pre><span style="color: #008080"><span style="color: #008080">1</span></span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">class</span></span>Main<span style="color: #0000ff"><span style="color: #0000ff">extends</span></span>Activity<span style="color: #0000ff"><span style="color: #0000ff">Implements</span></span><span style="color: #000000"><span style="color: #000000">onclicklistener{</span></span><span style="color: #008080"><span style="color: #008080">2</span></span> <span style="color: #0000ff"><span style="color: #0000ff">Private</span></span>Button save;<span style="color: #008000"><span style="color: #008000">//</span></span><span style="color: #008000"><span style="color: #008000">Insert Data button</span></span><span style="color: #008080"><span style="color: #008080">3</span></span> <span style="color: #0000ff"><span style="color: #0000ff">Private</span></span>Button delete;<span style="color: #008000"><span style="color: #008000">//</span></span><span style="color: #008000"><span style="color: #008000">Delete Data button</span></span><span style="color: #008080"><span style="color: #008080">4</span></span> <span style="color: #0000ff"><span style="color: #0000ff">Private</span></span>Button update;<span style="color: #008000"><span style="color: #008000">//</span></span><span style="color: #008000"><span style="color: #008000">Update Data button</span></span><span style="color: #008080"><span style="color: #008080">5</span></span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span><span style="color: #000000"><span style="color: #000000">onCreate (Bundle Savedinstancestate) {</span></span><span style="color: #008080"><span style="color: #008080">6</span></span> <span style="color: #0000ff"><span style="color: #0000ff">Super</span></span><span style="color: #000000"><span style="color: #000000">. OnCreate (savedinstancestate);</span></span><span style="color: #008080"><span style="color: #008080">7</span></span> <span style="color: #000000"><span style="color: #000000">Setcontentview (r.layout.main);</span></span><span style="color: #008080"><span style="color: #008080">8</span></span>Save=<span style="color: #000000"><span style="color: #000000">(Button) Findviewbyid (r.id.save);</span></span><span style="color: #008080"><span style="color: #008080">9</span></span>Delete=<span style="color: #000000"><span style="color: #000000">(Button) Findviewbyid (r.id.delete);</span></span><span style="color: #008080"><span style="color: #008080">Ten</span></span>Update=<span style="color: #000000"><span style="color: #000000">(Button) Findviewbyid (r.id.update);</span></span><span style="color: #008080"><span style="color: #008080"></span> one</span>Save.setonclicklistener (<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">);</span></span><span style="color: #008080"><span style="color: #008080"></span> a</span>Delete.setonclicklistener (<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">);</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Update.setonclicklistener (<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">);</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #000000"><span style="color: #000000"> } </span></span><span style="color: #008080"><span style="color: #008080"></span> the</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> public</span> <span style="color: #0000ff"><span style="color: #0000ff">void</span></span><span style="color: #000000"><span style="color: #000000">OnClick (View V) {</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Mysqliteopenhelper db=<span style="color: #0000ff"><span style="color: #0000ff">New</span></span>Mysqliteopenhelper (Main.<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span><span style="color: #000000"><span style="color: #000000">);</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #0000ff"><span style="color: #0000ff">Switch</span></span><span style="color: #000000"><span style="color: #000000">(v.getid ()) {</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> case</span><span style="color: #000000"><span style="color: #000000">r.id.save:</span></span><span style="color: #008080"><span style="color: #008080"></span> +</span>Db.insert ("insert into (name) values (?)",<span style="color: #0000ff"><span style="color: #0000ff">New</span></span>String[]{"zhang fei"<span style="color: #000000"><span style="color: #000000">});</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Toast.maketext (<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span>, "insert succeeded", 3000<span style="color: #000000"><span style="color: #000000">). Show ();</span></span><span style="color: #008080"><span style="color: #008080"></span> +</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> break</span><span style="color: #000000"><span style="color: #000000">;</span></span><span style="color: #008080"><span style="color: #008080"></span> a</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> case</span><span style="color: #000000"><span style="color: #000000">r.id.delete:</span></span><span style="color: #008080"><span style="color: #008080"></span> at</span>Db.insert ("delete from person where id=?",<span style="color: #0000ff"><span style="color: #0000ff">New</span></span>string[]{"1"<span style="color: #000000"><span style="color: #000000">});</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Toast.maketext (<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span>, "delete succeeded", 3000<span style="color: #000000"><span style="color: #000000">). Show ();</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> break</span><span style="color: #000000"><span style="color: #000000">;</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> case</span><span style="color: #000000"><span style="color: #000000">r.id.update:</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Db.insert ("update Person Set Name=?") where Id=1 ",<span style="color: #0000ff"><span style="color: #0000ff">New</span></span>String[]{"guan yu"<span style="color: #000000"><span style="color: #000000">});</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span>Toast.maketext (<span style="color: #0000ff"><span style="color: #0000ff"></span> this</span>, "update succeeded", 3000<span style="color: #000000"><span style="color: #000000">). Show ();</span></span><span style="color: #008080"><span style="color: #008080"></span> in</span> <span style="color: #0000ff"><span style="color: #0000ff"></span> break</span><span style="color: #000000"><span style="color: #000000">;</span></span><span style="color: #008080"><span style="color: #008080"></span> -</span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080"></span> to</span> <span style="color: #000000"><span style="color: #000000"> }</span></span><span style="color: #008080"><span style="color: #008080"></span> +</span>}</pre><span class="cnblogs_code_collapse"><span class="cnblogs_code_collapse">Activity Code</span></span><p><p></p></p><p><p>"android 9" sqliteopenhelper class, add-and-revise operation</p></p></span>
