Android Development: 14 Code Snippets to solve real-world problems

What are some of the problems you will encounter with Android programming? Here for beginners 14 pieces of simple and useful code, save when needed easily a key to get. This includes checking for an SD card, making an activity transparent, setting a handle in the screen element, and so on, and so on, the short code that is often used in practical applications.

1, to see if there is a memory card insert

String status=environment.getexternalstoragestate ();

if (Status.equals (enviroment.media_mounted))

{

Description has SD card insert

}

2, let an activity transparent

Layout is not set in OnCreate

This.settheme (r.style.theme_transparent);

The following is the definition of theme_transparent (note that TRANSPARENT_BG is a transparent picture)

3. Set handle in Screen element

Use Activity.findviewbyid to get a handle to the element on the screen that you can use to set or get any values that the object exposes.

TextView Msgtextview = (TextView) Findviewbyid (r.id.msg);

Msgtextview.settext (R.string.push_me);

4, send SMS

String body= "This is MMS demo";

Intent mmsintent = new Intent (intent.action_sendto, Uri.fromparts ("Smsto", number, null));

Mmsintent.putextra (Messaging.key_action_sendto_message_body, body);

Mmsintent.putextra (Messaging.key_action_sendto_compose_mode, true);

Mmsintent.putextra (Messaging.key_action_sendto_exit_on_sent, true);

StartActivity (mmsintent);

5, send MMS

StringBuilder sb = new StringBuilder ();

Sb.append ("file://");

Sb.append (Fd.getabsolutefile ());

Intent Intent = new Intent (intent.action_sendto, Uri.fromparts ("Mmsto", number, null));

Below extra datas are all optional.

Intent.putextra (Messaging.key_action_sendto_message_subject, SUBJECT);

Intent.putextra (Messaging.key_action_sendto_message_body, body);

Intent.putextra (Messaging.key_action_sendto_content_uri, sb.tostring ());

Intent.putextra (Messaging.key_action_sendto_compose_mode, Composemode);

Intent.putextra (Messaging.key_action_sendto_exit_on_sent, exitonsent);

StartActivity (Intent);

6, display toast

View Plaincopy

Toast.maketext (This._getapplicationcontext (), R.string._item, Toast.length_short). Show ();

7, Send mail

MIME = "Img/jpg";

Shareintent.setdataandtype (Uri.fromfile (FD), MIME);

Shareintent.putextra (Intent.extra_stream, Uri.fromfile (FD));

Shareintent.putextra (Intent.extra_subject, SUBJECT);

Shareintent.putextra (Intent.extra_text, body);

8. Register a Broadcastreceiver

Registerreceiver (Mmasterresetreciever, New Intentfilter ("OMS.action.MASTERRESET"));

Private Broadcastreceiver Mmasterresetreciever = new Broadcastreceiver ()

{

public void OnReceive (context context, Intent Intent)

{

String action = Intent.getaction ();

if ("Oms.action.MASTERRESET". Equals (Action))

{

Recoverdefaultconfig ();

}

}

};

9, the definition of contentobserver, monitoring a data table

Private Contentobserver Mdownloadsobserver = new Downloadschangeobserver (Downloads.content_uri);

Private class Downloadschangeobserver extends Contentobserver

{

Public downloadschangeobserver (URI Uri)

{

Super (New Handler ());

}

@Override

public void OnChange (Boolean selfchange) {}

}

10, access to mobile phone UA

Public String getuseragent ()

{

String user_agent = productproperties.get (Productproperties.user_agent_key, NULL);

return user_agent;

}

11, empty the phone cookies

Cookiesyncmanager.createinstance (Getapplicationcontext ());

Cookiemanager.getinstance (). Removeallcookie ();

12, the establishment of GPRS connection

Dial the GPRS link.

Private Boolean opendataconnection ()

{

Set up data connection.

DataConnection conn = Dataconnection.getinstance ();

if (connectmode = 0)

{

ret = conn.openconnection (Mcontext, "Cmwap", "Cmwap", "Cmwap");

}

Else

{

ret = conn.openconnection (Mcontext, "cmnet", "", "");

}

}

13. Preferenceactivity Usage

public class Setting extends preferenceactivity

{

public void OnCreate (Bundle savedinstancestate)

{

Super.oncreate (savedinstancestate);

Addpreferencesfromresource (r.xml.settings);

}

}

Setting.xml:

[Java]

Android:key= "Seting2″

android:title= "@string/seting2″

android:summary= "@string/seting2″/>

Android:key= "Seting1″

android:title= "@string/seting1″

android:summaryoff= "@string/seting1summaryoff"

android:summaryon= "@stringseting1summaryOff"/>

14. Get data from specified server via httpclient

Defaulthttpclient httpclient = new Defaulthttpclient ();

HttpGet method = new HttpGet ("/templets/default/index.html");

HttpResponse resp;

Reader reader = null;

try {

Allclientpnames.timeout

Httpparams params = new Basichttpparams ();

Params.setintparameter (Allclientpnames.connection_timeout, 10000);

Httpclient.setparams (params);

Resp = Httpclient.execute (method);

int status = Resp.getstatusline (). Getstatuscode ();

if (Status!= HTTPSTATUS.SC_OK)

{

return false;

}

HTTPSTATUS.SC_OK;

return true;

}

catch (Clientprotocolexception e)

{

TODO auto-generated Catch block

E.printstacktrace ();

}

catch (IOException E)

{

TODO auto-generated Catch block

E.printstacktrace ();

}

Finally

{

if (reader!= null)

Try

{

Reader.close ();

}

catch (IOException E)

{

TODO auto-generated Catch block

E.printstacktrace ();

}

}