13个简单有用的android开发代码

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

在OnCreate 中不设Layout,然后this.setTheme(R.style.Theme_Transparent);

3：获取屏幕宽高

DisplayMetrics dm = new DisplayMetrics();      
//获取窗口属性    
getWindowManager().getDefaultDisplay().getMetrics(dm);        
int screenWidth = dm.widthPixels;      
int screenHeight = dm.heightPixels;

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：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);

7: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();  
            }  
        }  
    };

8: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) {｝    
        }

9:获得 手机UA

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

10：清空手机上Cookie

CookieSyncManager.createInstance(getApplicationContext());   
   
CookieManager.getInstance().removeAllCookie();

11：建立GPRS 连接

private boolean openDataConnection() {   
   
DataConnection conn = DataConnection.getInstance();  
   
 if (connectMode == 0) {   
   
  ret = conn.openConnection(mContext, “cmwap”, “cmwap”, “cmwap”);  
   
 } else {   
   
  ret = conn.openConnection(mContext, “cmnet”, “”, “”);   
   
}  
   
}

12：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”/>

13: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();  
   
 }   
   
}