Android编程几个有用的代码片段

1、查看是否有存储卡插入 

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 

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.

TextView msgTextView = (TextView)findViewById(R.id.msg); 

msgTextView.setText(R.string.push_me);

4、发送短信

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

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、显示toast

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

7、发送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、注册一个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、定义ContentObserver，监听某个数据表

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

public String getUserAgent() 
{ 
    String user_agent = ProductProperties.get(ProductProperties.USER_AGENT_KEY, null); 

    return user_agent; 
}

11、清空手机上cookie

CookieSyncManager.createInstance (getApplicationContext() ); 

CookieManager.getInstance().removeAllCookie();

12、建立GPRS连接

//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

public class Setting extends PreferenceActivity 
{ 
    public void onCreate ( Bundle savedInstanceState ) 
        { 
            super.onCreate ( savedInstanceState ); 
            addPreferencesFromResource ( R.xml.settings );  
    } 
}

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

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(); 
             } 
      }

15.没有状态栏，没有应用标题栏

requestWindowFeature(Window.FEATURE_NO_TITLE);//无应用标题
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);//无状态栏