1、查看是否有存储卡插入 

1 String status=Environment.getExternalStorageState();
2  
3 if ( status.equals ( Enviroment.MEDIA_MOUNTED ) )
4 {
5     说明有SD卡插入
6 }

2、让某个Activity透明 

1 OnCreate中不设Layout
2  
3 this.setTheme(R.style.Theme_Transparent);
4  
5 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 TextView msgTextView = (TextView)findViewById(R.id.msg);
2  
3 msgTextView.setText(R.string.push_me);

4、发送短信

1 String body=”this is mms demo”;
2  
3 Intent mmsintent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts(”smsto”, number,null));
4  
5 mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY, body);
6 mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE, true);
7 mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT, true);
8  
9 startActivity(mmsintent);

5、发送彩信

01 StringBuilder sb = new StringBuilder();
02  
03 sb.append(”file://”);
04  
05 sb.append(fd.getAbsoluteFile());
06  
07 Intent intent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts(”mmsto”, number, null));
08  
09 // Below extra datas are all optional.
10 intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_SUBJECT, subject);
11 intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY, body);
12 intent.putExtra(Messaging.KEY_ACTION_SENDTO_CONTENT_URI, sb.toString());
13 intent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE, composeMode);
14 intent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT, exitOnSent);
15  
16 startActivity(intent);

6、显示toast

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

7、发送Mail

1 mime = “img/jpg”;
2              
3 shareIntent.setDataAndType(Uri.fromFile(fd), mime);
4  
5 shareIntent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(fd));
6  
7 shareIntent.putExtra(Intent.EXTRA_SUBJECT, subject);
8  
9 shareIntent.putExtra(Intent.EXTRA_TEXT, body);

8、注册一个BroadcastReceiver

01 registerReceiver(mMasterResetReciever, new IntentFilter(”OMS.action.MASTERRESET”));
02  
03 private BroadcastReceiver mMasterResetReciever = new BroadcastReceiver()
04 {
05         public void onReceive(Context context, Intent intent)
06        {
07             String action = intent.getAction();
08  
09             if (”oms.action.MASTERRESET”.equals(action) )
10            {
11                 RecoverDefaultConfig();
12             }
13         }
14 };

9、定义ContentObserver，监听某个数据表

01 private ContentObserver mDownloadsObserver = newDownloadsChangeObserver(Downloads.CONTENT_URI);
02  
03 private class DownloadsChangeObserver extends ContentObserver
04 {
05         public DownloadsChangeObserver(Uri uri)
06         {
07             super(new Handler());
08         }
09  
10         @Override
11         public void onChange(boolean selfChange) {}
12    
13 }

10、获得 手机UA 

1 public String getUserAgent()
2 {
3     String user_agent = ProductProperties.get(ProductProperties.USER_AGENT_KEY, null);
4      
5     return user_agent;
6 }
11、清空手机上cookie 
1 CookieSyncManager.createInstance (getApplicationContext() );
2  
3 CookieManager.getInstance().removeAllCookie();
12、建立GPRS连接 
01 //Dial the GPRS link.
02 private boolean openDataConnection()
03 {
04     // Set up data connection.
05     DataConnection conn = DataConnection.getInstance();    
06      
07     if ( connectMode == 0 )
08     {
09          ret = conn.openConnection ( mContext, “cmwap”, "cmwap”, "cmwap” );
10     }
11     else
12     {
13                 ret = conn.openConnection(mContext, “cmnet”, "", "");
14      }
15 }
13、PreferenceActivity 用法 
1 public class Setting extends PreferenceActivity
2 {
3     public void onCreate ( Bundle savedInstanceState )
4         {
5             super.onCreate ( savedInstanceState );
6             addPreferencesFromResource ( R.xml.settings ); 
7     }
8 }
Setting.xml: 
1 Android:key=”seting2″
2  
3          android:title=”@string/seting2″
4          android:summary=”@string/seting2″/>
5          android:key=”seting1″
6          android:title=”@string/seting1″
7          android:summaryOff=”@string/seting1summaryOff”
8            android:summaryOn=”@stringseting1summaryOff”/>
14、通过HttpClient从指定server获取数据
01 DefaultHttpClient httpClient = new DefaultHttpClient();
02  
03           HttpGet method = new HttpGet(“/templets/default/index.html”);
04           HttpResponse resp;
05           Reader reader = null;
06  
07           try {
08               // AllClientPNames.TIMEOUT
09               HttpParams params = new BasicHttpParams();
10               params.setIntParameter(AllClientPNames.CONNECTION_TIMEOUT, 10000);
11               
12               httpClient.setParams(params);
13               resp = httpClient.execute(method);
14               int status = resp.getStatusLine().getStatusCode();
15               
16               if (status != HttpStatus.SC_OK)
17               {
18                  return false;
19               }
20  
21               // HttpStatus.SC_OK;
22               return true;
23  
24           }
25         catch (ClientProtocolException e)
26         {
27               // TODO Auto-generated catch block
28               e.printStackTrace();
29         }
30        catch (IOException e)
31        {
32               // TODO Auto-generated catch block
33               e.printStackTrace();
34         }
35        finally
36       {
37               if (reader != null)
38               try
39              {
40                   reader.close();
41              }
42              catch (IOException e)
43              {
44                   // TODO Auto-generated catch block
45                   e.printStackTrace();
46              }
47       }