19个实用的Android代码片段

1：查看是否有存储卡插入

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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);

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.

1 2	TextView msgTextView = (TextView)findViewById(R.id.msg);     msgTextView.setText(R.string.push_me);

4:发送短信

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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

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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

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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

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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

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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

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

10：清空手机上Cookie

1 2	CookieSyncManager.createInstance(getApplicationContext());  CookieManager.getInstance().removeAllCookie();

 

11：建立GPRS 连接

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//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”, “”, “”);          }  }

 

12：PreferenceActivity 用法

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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

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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();                 }     }

14:显示toast

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

 

15:在当前Activity中启动另外一个Activity

1	startActivity(new Intent(this,目标Activity.class));

16:从当前ContentView从查找控件

(Button)findViewById(R.id.btnAbout)   
R.id.btnAbout指控件id。

 

17:获取屏幕宽高

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DisplayMetrics dm = new DisplayMetrics();   //获取窗口属性 getWindowManager().getDefaultDisplay().getMetrics(dm);    int screenWidth = dm.widthPixels;//320   int screenHeight = dm.heightPixels;//480

18:无标题栏、全屏

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//无标题栏   requestWindowFeature(Window.FEATURE_NO_TITLE);   //全屏模式   getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,   WindowManager.LayoutParams.FLAG_FULLSCREEN); 注意在setContentView()之前调用，否则无效。

 

19:注册activity

所有用到的Activity都必须在AndroidManifest.xml中注册，否则会报空指针错误。
如：，注意是包名+类名。