14 useful code snippets for Android programming

: Check whether a memory card is inserted.

1. String status = environment. getexternalstoragestate ();
2. If (status. Equals (enviroment. media_mounted ))
3. {
4. SD card insertion
5. }

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2: Make an activity transparent

1. Layout is not set in oncreate.
3. This. settheme (R. style. theme_transparent );
5. The following is the definition of theme_transparent (note that transparent_bg is a transparent image)

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3: Set the handle in the screen element
Use activity. findviewbyid to obtain the handle of the elements on the screen. With this handle, you can set or obtain any value exposed to this object.

1. Textview msgtextview = (textview) findviewbyid (R. Id. msg );
2. Msgtextview. settext (R. String. push_me );

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4: send SMS

1. String body = "this is MMS Demo ";
3. Intent mmsintent = new intent (intent. action_sendto, Uri. fromparts ("smsto", number, null ));
   
4. Mmsintent. putextra (messaging. key_action_sendto_message_body, body );
5. Mmsintent. putextra (messaging. key_action_sendto_compose_mode, true );
6. Mmsintent. putextra (messaging. key_action_sendto_exit_on_sent, true );
7. Startactivity (mmsintent );

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5. Send MMS messages

1. Stringbuilder sb = new stringbuilder ();
3. SB. append ("file ://");
5. SB. append (FD. getabsolutefile ());
7. Intent intent = new intent (intent. action_sendto, Uri. fromparts ("mmsto", number, null ));
   
8. // Below extra datas are all optional.
9. Intent. putextra (messaging. key_action_sendto_message_subject, subject );
10. Intent. putextra (messaging. key_action_sendto_message_body, body );
11. Intent. putextra (messaging. key_action_sendto_content_uri, SB. tostring ());
12. Intent. putextra (messaging. key_action_sendto_compose_mode, composemode );
13. Intent. putextra (messaging. key_action_sendto_exit_on_sent, exitonsent );
15. Startactivity (intent );

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6: Display toast

1. Toast. maketext (this. _ getapplicationcontext (), R. String. _ item, Toast. length_short). Show ();

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7: Send mail

1. Mime = "img/jpg ";
2. Using intent. setdataandtype (URI. fromfile (FD), mime );
3. Extends intent. putextra (intent. extra_stream, Uri. fromfile (FD ));
4. Specify intent. putextra (intent. extra_subject, subject );
5. Extends intent. putextra (intent. extra_text, body );

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8: register a broadcastreceiver

1. Registerreceiver (mmasterresetreciever, new intentfilter ("OMS. Action. masterreset "));
   
2. Private broadcastreceiver mmasterresetreciever = new broadcastreceiver (){
3. Public void onreceive (context, intent ){
4. String action = intent. getaction ();
5. If ("OMS. Action. masterreset". Equals (Action )){
6. Recoverdefaconfig config ();
7. }
8. }
9. };

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9: Define contentobserver to listen to a data table

1. Private contentobserver mdownloadsobserver = new downloadschangeobserver (downloads. content_uri );
   
2. Private class downloadschangeobserver extends contentobserver {
3. Public downloadschangeobserver (URI ){
4. Super (new handler ());
5. }
6. @ Override
7. Public void onchange (Boolean selfchange ){}
8. }

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10: Get the UA

1. Public String getuseragent ()
2. {
3. String user_agent = productproperties. Get (productproperties. user_agent_key, null );
   
4. Return user_agent;
5. }

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11: Clear cookies on mobile phones

1. Cookiesyncmanager. createinstance (getapplicationcontext ());
2. Cookiemanager. getinstance (). removeallcookie ();

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12. Establish a GPRS connection

1. // Dial the GPRS link.
2. Private Boolean opendataconnection (){
3. // Set up data connection.
4. Dataconnection conn = dataconnection. getinstance ();
5. If (connectmode = 0 ){
6. Ret = conn. openconnection (mcontext, "cmwap ");
   
7. } Else {
8. Ret = conn. openconnection (mcontext, "cmnet", "", "");
9. }
10. }

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13: preferenceactivity usage

1. Public class setting extends preferenceactivity
2. {
3. Public void oncreate (bundle savedinstancestate ){
4. Super. oncreate (savedinstancestate );
5. Addpreferencesfromresource (R. xml. settings );
6. }
7. }

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Setting. xml:

1. Android: Key = "seting2 ″
2. Android: Title = "@ string/seting2 ″
3. Android: Summary = "@ string/seting2"/>
4. Android: Key = "seting1 ″
5. Android: Title = "@ string/seting1 ″
6. Android: summaryoff = "@ string/seting1summaryoff"
7. Android: summaryon = "@ stringseting1summaryoff"/>

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14. Use httpclient to obtain data from a specified server

1. Defaulthttpclient httpclient = new defaulthttpclient ();
2. Httpget method = new httpget ("http://www.baidu.com/1.html ");
3. Httpresponse resp;
4. Reader reader = NULL;
5. Try {
6. // Allclientpnames. Timeout
7. Httpparams Params = new basichttpparams ();
8. Params. setintparameter (allclientpnames. connection_timeout, 10000 );
   
9. Httpclient. setparams (Params );
10. Resp = httpclient.exe cute (method );
11. Int status = resp. getstatusline (). getstatuscode ();
12. If (status! = Httpstatus. SC _ OK) return false;
13. // Httpstatus. SC _ OK;
14. Return true;
15. } Catch (clientprotocolexception e ){
16. // Todo auto-generated Catch Block
17. E. printstacktrace ();
18. } Catch (ioexception e ){
19. // Todo auto-generated Catch Block
20. E. printstacktrace ();
21. } Finally {
22. If (reader! = NULL) Try {
23. Reader. Close ();
24. } Catch (ioexception e ){
25. // Todo auto-generated Catch Block
26. E. printstacktrace ();
27. }
28. }

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