Android编程14个很有用的代码片段

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 }
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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）
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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);
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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);
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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);
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6、显示toast
1 Toast.makeText(this._getApplicationContext(), R.string._item, Toast.LENGTH_SHORT).show();
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7、发送Mail
01    
02 mime = “img/jpg”; 
03              
04 shareIntent.setDataAndType(Uri.fromFile(fd), mime); 
05  
06 shareIntent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(fd)); 
07  
08 shareIntent.putExtra(Intent.EXTRA_SUBJECT, subject); 
09  
10 shareIntent.putExtra(Intent.EXTRA_TEXT, body);
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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 };
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9、定义ContentObserver，监听某个数据表
01 private ContentObserver mDownloadsObserver = new DownloadsChangeObserver(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 } 
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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 }
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11、清空手机上cookie
1 CookieSyncManager.createInstance (getApplicationContext() ); 
2  
3 CookieManager.getInstance().removeAllCookie();
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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 }
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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 }
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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、通过HttpClient从指定server获取数据
01 DefaultHttpClient httpClient = new DefaultHttpClient(); 
02           HttpGet method = new HttpGet(“http://www.ligotop.com/index.html”); 
03           HttpResponse resp; 
04           Reader reader = null; 
05           try { 
06               // AllClientPNames.TIMEOUT 
07               HttpParams params = new BasicHttpParams(); 
08               params.setIntParameter(AllClientPNames.CONNECTION_TIMEOUT, 10000); 
09               
10               httpClient.setParams(params); 
11               resp = httpClient.execute(method); 
12               int status = resp.getStatusLine().getStatusCode(); 
13               
14               if (status != HttpStatus.SC_OK) 
15               {
16                  return false; 
17               }
18               // HttpStatus.SC_OK; 
19               return true; 
20           } 
21         catch (ClientProtocolException e) 
22         { 
23               // TODO Auto-generated catch block 
24               e.printStackTrace(); 
25         <