Android编程14个很有用的代码片段

来源：互联网发布：什么是矩阵的秩编辑：程序博客网时间：2024/04/27 16:59

原文地址：http://iwapzone.com/html/article/2012/0826/275.html

1、查看是否有存储卡插入

Stringstatus=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, newIntentFilter(”OMS.action.MASTERRESET”));

private BroadcastReceiver mMasterResetReciever = newBroadcastReceiver()
{
       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 = newDownloadsChangeObserver(Downloads.CONTENT_URI);

private class DownloadsChangeObserver extendsContentObserver
{
       public DownloadsChangeObserver(Uri uri)
       {
           super(new Handler());
       }

@Override
public void onChange(boolean selfChange) {}

}

10、获得手机UA

public StringgetUserAgent()
{
    Stringuser_agent =ProductProperties.get(ProductProperties.USER_AGENT_KEY,null);

    returnuser_agent;
}

11、清空手机上cookie

CookieSyncManager.createInstance(getApplicationContext() );

CookieManager.getInstance().removeAllCookie();

12、建立GPRS连接

//Dial theGPRS link.
private boolean openDataConnection()
{
    // Set updata 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 voidonCreate ( 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();
            }
     }

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