转 20个Android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();

16:在当前Activity中启动另外一个Activity

startActivity(new Intent(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

DisplayMetrics dm = new DisplayMetrics();

//获取窗口属性

getWindowManager().getDefaultDisplay().getMetrics(dm);

int screenWidth = dm.widthPixels;//320

int screenHeight = 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。

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