How to save a ListView into a xml file in Android? -

i developing android app capable of detecting ble signals , list them in listview. after scan period of time stop scanning. here code (it same in developers page):

scanbleactivity.class (extends scanbaseactivty):

public class scanbleactivity extends scanbaseactivity {  private bluetoothadapter mbluetoothadapter; private boolean mscanning; private handler mhandler = new handler();   // stops scanning after 10 seconds. private static final long scan_period = 20000;    /* (non-javadoc)   * @see com.zishao.bletest.scanbaseactivity#initscanbluetooth()   */  protected void initscanbluetooth() {    bluetoothmanager manager = (bluetoothmanager) getsystemservice(context.bluetooth_service);    mbluetoothadapter = manager.getadapter();    startscanlen(true);   }    @override  protected void ondestroy() {     super.ondestroy();     if (mscanning) {     startscanlen(false);     } }    /**   *    * @param enable   */    private void startscanlen(final boolean enable) {     if (enable) {         // stops scanning after pre-defined scan period.         mhandler.postdelayed(new runnable() {             @override             public void run() {                 mscanning = false;                 mbluetoothadapter.stoplescan(mlescancallback);             }         }, scan_period);          mscanning = true;         mbluetoothadapter.startlescan(mlescancallback);     } else {         mscanning = false;         mbluetoothadapter.stoplescan(mlescancallback);     } }  // device scan callback. private bluetoothadapter.lescancallback mlescancallback =     new bluetoothadapter.lescancallback() {         @override         public void onlescan(final bluetoothdevice device, int rssi, byte[] scanrecord) {             adddevice(device, rssi);          }     }; 

adddevice implemented in other class, in case scanbaseactivity:

scanbaseactivity (which extends listactivity):

abstract public class scanbaseactivity extends listactivity {  protected ledevicelistadapter mledevicelistadapter;  @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_devices_scan); mledevicelistadapter = new ledevicelistadapter(this, new arraylist<bluetoothdevice>()); this.setlistadapter(mledevicelistadapter); initscanbluetooth(); }   /**  * start scan bluetooth  *   */ abstract protected void initscanbluetooth();  @override protected void onlistitemclick(listview l, view v, int position, long id) { bluetoothdevice device = (bluetoothdevice) mledevicelistadapter.getitem(position); parceluuid[] uuids = device.getuuids(); string uuidstring = "getting uuid's " + device.getname() + ";uuid:"; if (null != uuids && uuids.length > 0) {     uuidstring += uuids[0].getuuid().tostring(); } else {     uuidstring += "empty"; } toast.maketext(this, uuidstring, toast.length_long).show(); }    /**   * @param device   */  protected synchronized void adddevice(final bluetoothdevice device, final int rssi) {     runonuithread(new runnable() {         @override         public void run() {             mledevicelistadapter.adddevice(device, rssi);             mledevicelistadapter.notifydatasetchanged();         }     }); } } 

all information detect (name, address, rssi, etc) listed in listview. listview have implemented adapter called baseadapter. part of code of adapter following:

public class ledevicelistadapter extends baseadapter { private list<bluetoothdevice> data; private activity context; private final hashmap<bluetoothdevice, integer> rssimap = new hashmap<bluetoothdevice,   integer>();    public ledevicelistadapter(activity context, list<bluetoothdevice> data) {     this.data = data;     this.context = context; }  public synchronized void adddevice(bluetoothdevice device, int rssi) {     if(!data.contains(device) ){     data.add(device);     }     rssimap.put(device, rssi); }  @override public int getcount() {     return data.size(); }  @override public object getitem(int position) {     return data.get(position); }  @override public long getitemid(int position) {     return position; }  @override public view getview(int position, view convertview, viewgroup parent) {     if (null == convertview) {         layoutinflater minflater =             (layoutinflater) context.getsystemservice(context.layout_inflater_service);         convertview = minflater.inflate(r.layout.leaf_devices_list_item, null);         convertview.settag(new deviceview(convertview));     }     deviceview view = (deviceview) convertview.gettag();     view.init((bluetoothdevice) getitem(position), null);     return convertview; }  public class deviceview {        private textview title;     private textview status;     private textview type;     private textview address;     private textview rssivalue;      public deviceview(view view) {         title = (textview) view.findviewbyid(r.id.device_name);         status = (textview) view.findviewbyid(r.id.device_status_txt);         type = (textview) view.findviewbyid(r.id.device_type_txt);         address = (textview) view.findviewbyid(r.id.device_address_txt);         rssivalue = (textview) view.findviewbyid(id.signal_intensity_txt);     } 

when scan finishes save listview file (if possible xml file) don´t know , code should use in project save it. imortant use timestamp in file know when saved. can me or give me clues??

new: code edited show code scanbaseactivity , scanbleactivity!!!

i see 1 problem constructor.

    public ledevicelistadapter(activity context, list<bluetoothdevice> data) {     //edit::     //add following line     super(context, r.layout.leaf_devices_list_item, data);      this.data = data;     this.context = context;  } 

calling super constructor passes reference of data baseadapter. then, baseadapter able handle changes in list.