Android开发学习笔记：Android很有用的代码片段
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. TextViewmsgTextView=(TextView)findViewById(R.id.msg); msgTextView.setText(R.string.push_me); 4:发送短信 Stringbody=”thisismmsdemo”; Intentmmsintent=newIntent(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 StringBuildersb=newStringBuilder(); sb.append(”file://”); sb.append(fd.getAbsoluteFile()); Intentintent=newIntent(Intent.ACTION_SENDTO,Uri.fromParts(”mmsto”,number,null)); //Belowextradatasarealloptional. 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,newIntentFilter(”oms.action.MASTERRESET”)); privateBroadcastReceivermMasterResetReciever=newBroadcastReceiver(){ publicvoidonReceive(Contextcontext,Intentintent){ Stringaction=intent.getAction(); if(”oms.action.MASTERRESET”.equals(action)){ RecoverDefaultConfig(); } } }; 9:定义ContentObserver，监听某个数据表 privateContentObservermDownloadsObserver=newDownloadsChangeObserver(Downloads.CONTENT_URI); privateclassDownloadsChangeObserverextendsContentObserver{ publicDownloadsChangeObserver(Uriuri){ super(newHandler()); } @Override publicvoidonChange(booleanselfChange){｝ } 10:获得手机UA publicStringgetUserAgent(){ 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 //DialtheGPRSlink. privatebooleanopenDataConnection(){ //Setupdataconnection. DataConnectionconn=DataConnection.getInstance(); if(connectMode==0){ ret=conn.openConnection(mContext,“cmwap”,“cmwap”,“cmwap”); }else{ ret=conn.openConnection(mContext,“cmnet”,“”,“”); } } 13：PreferenceActivity用法 publicclassSettingextendsPreferenceActivity｛ publicvoidonCreate(BundlesavedInstanceState){ 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 DefaultHttpClienthttpClient=newDefaultHttpClient(); HttpGetmethod=newHttpGet(“http://www.baidu.com/1.html”); HttpResponseresp; Readerreader=null; try{ //AllClientPNames.TIMEOUT HttpParamsparams=newBasicHttpParams(); params.setIntParameter(AllClientPNames.CONNECTION_TIMEOUT,10000); httpClient.setParams(params); resp=httpClient.execute(method); intstatus=resp.getStatusLine().getStatusCode(); if(status!=HttpStatus.SC_OK)returnfalse; //HttpStatus.SC_OK; returntrue; }catch(ClientProtocolExceptione){ //TODOAuto-generatedcatchblock e.printStackTrace(); }catch(IOExceptione){ //TODOAuto-generatedcatchblock e.printStackTrace(); }finally{ if(reader!=null)try{ reader.close(); }catch(IOExceptione){ //TODOAuto-generatedcatchblock e.printStackTrace(); } } 15:显示toast Toast.makeText(this._getApplicationContext(),R.string._item,Toast.LENGTH_SHORT).show(); 16:在当前Activity中启动另外一个Activity startActivity(newIntent(this,目标Activity.class)); 17:从当前ContentView从查找控件 (Button)findViewById(R.id.btnAbout) R.id.btnAbout指控件id。 18:获取屏幕宽高 DisplayMetricsdm=newDisplayMetrics(); //获取窗口属性 getWindowManager().getDefaultDisplay().getMetrics(dm); intscreenWidth=dm.widthPixels;//320 intscreenHeight=dm.heightPixels;//480 19:无标题栏、全屏 //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。 20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。 会持续更新...................... 本文转自 lingdududu 51CTO博客，原文链接http://blog.51cto.com/liangruijun/722171
