Android中15个很实用的代码片段(技巧)

1：查看是否有存储卡插入

1 2 3 4 5 String status= Environment .getExternalStorageState ( ) ; if ( status.equals ( Enviroment.MEDIA_MOUNTED ) ) { 说明有SD卡插入 }

2：让某个Activity透明 OnCreate中不设Layout

1 this .setTheme ( R.style .Theme_Transparent ) ;

以下是Theme_Transparent的定义（注意transparent_bg是一副透明的图片）

3：在屏幕元素中设置句柄 使用Activity.findViewById来取得屏幕上的元素的句柄. 使用该句柄您可以设置或获取任何该对象外露的值.

1 2 TextView msgTextView = ( TextView) findViewById( R.id .msg ) ; msgTextView.setText ( R.string .push_me ) ;

4:发送短信

1 2 3 4 5 6 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:发送彩信

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 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) ;

7：发送Mail

1 2 3 4 5 6 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:注册一个BroadcastReceiver

1 2 3 4 5 6 7 8 9 10 11 12 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:定义ContentObserver，监听某个数据表

1 2 3 4 5 6 7 8 9 10 11 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:获得 手机UA

1 2 3 4 5 public String getUserAgent( ) { String user_agent = ProductProperties.get ( ProductProperties.USER_AGENT_KEY , null ) ; return user_agent; }

11：清空手机上Cookie

1 2 CookieSyncManager.createInstance ( getApplicationContext( ) ) ; CookieManager.getInstance ( ) .removeAllCookie ( ) ;

12：建立GPRS连接

1 2 3 4 5 6 7 8 9 10 11 //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 用法

1 2 3 4 5 6 7 8 9 10 public class Setting extends PreferenceActivity   ｛   public void onCreate( Bundle savedInstanceState) { super .onCreate ( savedInstanceState) ; addPreferencesFromResource( R.xml .settings ) ； }   ｝ 1 2 3 4 5 6 7 8 9 10 Setting.xml:   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:通过HttpClient从指定server获取数据

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 DefaultHttpClient httpClient = new DefaultHttpClient( ) ; HttpGet method = new HttpGet( “http: //www.baidu.com/1.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 ( ) ; } }

15:显示toast

1 Toast.makeText ( this ._getApplicationContext( ) , R.string ._item, Toast.LENGTH_SHORT ) .show ( ) ;