转： N个Android很有用的代码片段

我也无法找到原文出自哪里，网上转帖太多了！

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);

Theme_Transparent的定义中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);

根本没有第6个？？？          

7：发送Mail

String 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。