Code snippets frequently used in Android development (1)

Document directory

• 1. image rotation:
• 2. Obtain the mobile phone number:
• 3. format the string in string. xml:
• 4. How to set full screen for Android:
• 5. Set activity to dialog:
• 6. Check whether the current network is connected:
• 7. Check whether an intent is valid:
• 8. Android Dialing:
• 9. Send email in Android:
• 10. Open a browser in Android:
• 11. Android obtains the unique identifier of a device:
• 12. Obtain the IP address in Android:
• 13. Android obtains the memory card path and usage:
• 14 Add a new contact to Android:
• 15. View battery usage:

1. image rotation:

Bitmap bitmaporg = bitmapfactory. decoderesource (this. getcontext (). getresources (), R. drawable. moon); matrix = new matrix (); matrix. postrotate (-90); // Rotation Angle bitmap resizedbitmap = bitmap. createbitmap (bitmaporg, 0, 0, bitmaporg. getwidth (), bitmaporg. getheight (), matrix, true); bitmapdrawable BMI = new bitmapdrawable (resizedbitmap );

2. Obtain the mobile phone number:

// Create telephonymanager TM = (telephonymanager) // create a connection activity with the mobile phone. getsystemservice (context. telephony_service); // obtain the mobile phone number string phoneid = TM. getline1number (); // remember to add <uses-permissionandroid: Name = "android. permission. read_phone_state "/> // The program cannot be implemented on the simulator and must be connected to the mobile phone

3. format the string in string. xml:

// in strings.xml..<string name="my_text">Thanks for visiting %s. You age is %d!</string>          // and in the java code:String.format(getString(R.string.my_text), "oschina", 33);

4. How to set full screen for Android: A. Set it in Java code

/** Full screen setting: Hide all decorations in the window */requestwindowfeature (window. feature_no_title); getwindow (). setflags (windowmanager. layoutparams. flag_fullscreen, windowmanager. layoutparams. flag_fullscreen );

B. Configure in androidmanifest. xml

<activity android:name=".Login.NetEdit"  android:label="@string/label_net_Edit"           android:screenOrientation="portrait" android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen"><intent-filter><action android:name="android.intent.Net_Edit" /><category android:name="android.intent.category.DEFAULT" /></intent-filter></activity>

5. Set activity to dialog:

Configure theme for activity nodes in androidmanifest. XML as follows:

android:theme="@android:style/Theme.Dialog"

6. Check whether the current network is connected:

ConnectivityManager con=(ConnectivityManager)getSystemService(Activity.CONNECTIVITY_SERVICE);   boolean wifi=con.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting();  boolean internet=con.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnectedOrConnecting(); 

Add permissions in androidmanifest. xml:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

7. Check whether an intent is valid:

public static boolean isIntentAvailable(Context context, String action) {    final PackageManager packageManager = context.getPackageManager();    final Intent intent = new Intent(action);    List<ResolveInfo> list =            packageManager.queryIntentActivities(intent,                    PackageManager.MATCH_DEFAULT_ONLY);    return list.size() > 0;}

8. Android Dialing:

try {   Intent intent = new Intent(Intent.ACTION_CALL);   intent.setData(Uri.parse("tel:+110"));   startActivity(intent);} catch (Exception e) {   Log.e("SampleApp", "Failed to invoke call", e);}

9. Send email in Android:

Intent I = new intent (intent. action_send); // I. settype ("text/plain"); // use this line for the simulator I. settype ("message/rfc822"); // use this line on the real machine I. putextra (intent. extra_email, new string [] {"test@gmail.com", "test@163.com}); I. putextra (intent. extra_subject, "subject goes here"); I. putextra (intent. extra_text, "body goes here"); startactivity (intent. createchooser (I, "select email application. "));

10. Open a browser in Android:

Intent viewIntent = new     Intent("android.intent.action.VIEW",Uri.parse("http://vaiyanzi.cnblogs.com"));startActivity(viewIntent);

11. Android obtains the unique identifier of a device:

String android_id = Secure.getString(getContext().getContentResolver(), Secure.ANDROID_ID);

12. Obtain the IP address in Android:

public String getLocalIpAddress() {    try {        for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {            NetworkInterface intf = en.nextElement();            for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {                InetAddress inetAddress = enumIpAddr.nextElement();                if (!inetAddress.isLoopbackAddress()) {                    return inetAddress.getHostAddress().toString();                }            }        }    } catch (SocketException ex) {        Log.e(LOG_TAG, ex.toString());    }    return null;}

13. Android obtains the memory card path and usage:

/** Obtain the memory card path */file sdcarddir = environment. getexternalstoragedirectory ();/** statfs View File System space usage */statfs = new statfs (sdcarddir. getpath ();/** block size */long blocksize = statfs. getblocksize ();/** total number of blocks */long totalblocks = statfs. getblockcount ();/** number of blocks in use */long availableblocks = statfs. getavailableblocks ();

14 Add a new contact to Android:

private Uri insertContact(Context context, String name, String phone) {          ContentValues values = new ContentValues();       values.put(People.NAME, name);       Uri uri = getContentResolver().insert(People.CONTENT_URI, values);       Uri numberUri = Uri.withAppendedPath(uri, People.Phones.CONTENT_DIRECTORY);       values.clear();              values.put(Contacts.Phones.TYPE, People.Phones.TYPE_MOBILE);       values.put(People.NUMBER, phone);       getContentResolver().insert(numberUri, values);              return uri;}

15. View battery usage:

Intent intentBatteryUsage = new Intent(Intent.ACTION_POWER_USAGE_SUMMARY);        startActivity(intentBatteryUsage);