Android编程15个很有用的代码片段

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); 
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(“http://www.baidu.com/1.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:显示toast 
Toast.makeText(this._getApplicationContext(), R.string._item, Toast.LENGTH_SHORT).show();