Android编程中14个解决实际问题的代码片段

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

view plaincopyToast.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());}@Overridepublic 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:[java]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();}}