Android开发常用代码片段-优快云博客

本文介绍了多项Android开发实用技巧，包括检查SD卡状态、使Activity透明、屏幕元素句柄设置、发送短信与彩信、显示Toast消息、发送邮件、注册BroadcastReceiver、定义ContentObserver监听数据表、获取手机UA、清除cookies、建立GPRS连接、使用PreferenceActivity、通过HttpClient获取数据等。

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1、查看是否有存储卡插入

1

String
 status=Environment.getExternalStorageState();

2

3

if(
 status.equals ( Enviroment.MEDIA_MOUNTED ) )

4

{

5

说明有SD卡插入

6

}

2、让某个Activity透明

1

OnCreate中不设Layout

2

3

this.setTheme(R.style.Theme_Transparent);

4

5

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.

1

TextView
 msgTextView = (TextView)findViewById(R.id.msg);

2

3

msgTextView.setText(R.string.push_me);

4、发送短信

1

String
 body=”thisis
 mms demo”;

2

3

Intent
 mmsintent =newIntent(Intent.ACTION_SENDTO,
 Uri.fromParts(”smsto”, number,null));

4

5

mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY,
 body);

6

mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE,true);

7

mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT,true);

8

9

startActivity(mmsintent);

5、发送彩信

01

StringBuilder
 sb =newStringBuilder();

02

03

sb.append(”file://”);

04

05

sb.append(fd.getAbsoluteFile());

06

07

Intent
 intent =newIntent(Intent.ACTION_SENDTO,
 Uri.fromParts(”mmsto”, number,null));

08

09

//
 Below extra datas are all optional.

10

intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_SUBJECT,
 subject);

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intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY,
 body);

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intent.putExtra(Messaging.KEY_ACTION_SENDTO_CONTENT_URI,
 sb.toString());

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intent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE,
 composeMode);

14

intent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT,
 exitOnSent);

15

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startActivity(intent);

6、显示toast

1

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

7、发送Mail

1

mime
 = “img/jpg”;

2

3

shareIntent.setDataAndType(Uri.fromFile(fd),
 mime);

4

5

shareIntent.putExtra(Intent.EXTRA_STREAM,
 Uri.fromFile(fd));

6

7

shareIntent.putExtra(Intent.EXTRA_SUBJECT,
 subject);

8

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shareIntent.putExtra(Intent.EXTRA_TEXT,
 body);

8、注册一个BroadcastReceiver

01

registerReceiver(mMasterResetReciever,newIntentFilter(”OMS.action.MASTERRESET”));

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privateBroadcastReceiver
 mMasterResetReciever =newBroadcastReceiver()

04

{

05

publicvoidonReceive(Context
 context, Intent intent)

06

{

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String
 action = intent.getAction();

08

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if(”oms.action.MASTERRESET”.equals(action)
 )

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{

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RecoverDefaultConfig();

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}

13

}

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};

9、定义ContentObserver，监听某个数据表

01

privateContentObserver
 mDownloadsObserver =newDownloadsChangeObserver(Downloads.CONTENT_URI);

02

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privateclassDownloadsChangeObserverextendsContentObserver

04

{

05

publicDownloadsChangeObserver(Uri
 uri)

06

{

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super(newHandler());

08

}

09

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@Override

11

publicvoidonChange(booleanselfChange)
 {}

12

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}

10、获得手机UA

1

publicString
 getUserAgent()

2

{

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String
 user_agent = ProductProperties.get(ProductProperties.USER_AGENT_KEY,null);

4

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returnuser_agent;

6

}

11、清空手机上cookie

1

CookieSyncManager.createInstance
 (getApplicationContext() );

2

3

CookieManager.getInstance().removeAllCookie();

12、建立GPRS连接

01

//Dial
 the GPRS link.

02

privatebooleanopenDataConnection()

03

{

04

//
 Set up data connection.

05

DataConnection
 conn = DataConnection.getInstance();

06

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if(
 connectMode ==0)

08

{

09

ret
 = conn.openConnection ( mContext, “cmwap”,"cmwap”,
 "cmwap”
 );

10

}

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else

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{

13

ret
 = conn.openConnection(mContext, “cmnet”,"","");

14

}

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}

13、PreferenceActivity 用法

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publicclassSettingextendsPreferenceActivity

2

{

3

publicvoidonCreate
 ( Bundle savedInstanceState )

4

{

5

super.onCreate
 ( savedInstanceState );

6

addPreferencesFromResource
 ( R.xml.settings );

7

}

8

}

Setting.xml:

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Android:key=”seting2″

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android:title=”@string/seting2″

4

android:summary=”@string/seting2″/>

5

android:key=”seting1″

6

android:title=”@string/seting1″

7

android:summaryOff=”@string/seting1summaryOff”

8

android:summaryOn=”@stringseting1summaryOff”/>

14、通过HttpClient从指定server获取数据

01

DefaultHttpClient
 httpClient =newDefaultHttpClient();

02

03

HttpGet
 method =newHttpGet(“/templets/default/index.html”);

04

HttpResponse
 resp;

05

Reader
 reader =null;

06

07

try{

08

//
 AllClientPNames.TIMEOUT

09

HttpParams
 params =newBasicHttpParams();

10

params.setIntParameter(AllClientPNames.CONNECTION_TIMEOUT,10000);

11

12

httpClient.setParams(params);

13

resp
 = httpClient.execute(method);

14

intstatus
 = resp.getStatusLine().getStatusCode();

15

16

if(status
 != HttpStatus.SC_OK)

17

{

18

returnfalse;

19

}

20

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//
 HttpStatus.SC_OK;

22

returntrue;

23

24

}

25

catch(ClientProtocolException
 e)

26

{

27

//
 TODO Auto-generated catch block

28

e.printStackTrace();

29

}

30

catch(IOException
 e)

31

{

32

//
 TODO Auto-generated catch block

33

e.printStackTrace();

34

}

35

finally

36

{

37

if(reader
 !=null)

38

try

39

{

40

reader.close();

41

}

42

catch(IOException
 e)

43

{

44

//
 TODO Auto-generated catch block

45

e.printStackTrace();

46

}

47

}