我正在尝试构建一个应用程序，在该应用程序中（通过信号强度）检测到最近的信标的强度，并且必须调用相应的API（将信标ID作为参数）。该应用程序首次询问位置并运行良好（检测到最近的信标）。但是在我关闭应用程序并重新打开它之后，信标ID始终为空（正在使用信标ID设置string2变量）。为什么它第一次运行而不是以后运行？
每当我清除该应用程序的数据时，该应用程序都会询问位置并正常运行。我已经将整个段再次编码了三遍，但是遇到了同样的问题。
我尝试通过日志语句跟踪流。我观察到onBeaconServiceConnect（）方法不会第二次执行（除非清除了应用程序的数据）。
AsyncTask：
public class Navigate extends AsyncTask<String, String, String> {
protected String doInBackground(String... strings) {
//REST Query
String cs, ps = null;
//Here bid is a field and it will be set to Beacon ID of the nearest beacon.
while (!bid.equals(strings[1])) {
try {
imageURL=callAPI("bid1","bid3");
Log.e("BeaconID", bid); //The default value of bid will be printed and not the beacon ID.
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
}
Log.e("Debug", "Step3");
return "none";
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
Toast.makeText(getApplicationContext(), "onProgressUpdate", Toast.LENGTH_SHORT).show();
mNetworkImageView = (NetworkImageView) findViewById(R.id.mapImage);
mImageLoader = CustomVolleyRequestQueue.getInstance(getApplicationContext()).getImageLoader();
mImageLoader.get(values[0], ImageLoader.getImageListener(mNetworkImageView, R.mipmap.ic_launcher_round, android.R.drawable.ic_menu_report_image));
Log.e("Image Published", values[0]);
mNetworkImageView.setImageUrl(values[0], mImageLoader);
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
progressDialog.dismiss();
tv.setText(s);
}
}
OnBeaconServiceConnect：-
public void onBeaconServiceConnect() {
//Constructing a new Region object to be used for Ranging or Monitoring
region = new Region("myBeaons", Identifier.parse("23542266-18D1-4FE4-B4A1-23F8195B9D39"), null, null);
//Specifies a class that should be called each time the BeaconService sees or stops seeing a Region of beacons.
beaconManager.addMonitorNotifier(new MonitorNotifier() {
/*
This override method is runned when some beacon will come under the range of device.
*/
@Override
public void didEnterRegion(Region region) {
System.out.println("ENTER ------------------->");
try {
//Tells the BeaconService to start looking for beacons that match the passed Region object
// , and providing updates on the estimated mDistance every seconds while beacons in the Region
// are visible.
beaconManager.startRangingBeaconsInRegion(region);
} catch (RemoteException e) {
e.printStackTrace();
}
Log.e("Debug", "Step10");
}
/*
This override method is runned when beacon that comes in the range of device
,now been exited from the range of device.
*/
@Override
public void didExitRegion(Region region) {
System.out.println("EXIT----------------------->");
try {
//Tells the BeaconService to stop looking for beacons
// that match the passed Region object and providing mDistance
// information for them.
beaconManager.stopRangingBeaconsInRegion(region);
} catch (RemoteException e) {
e.printStackTrace();
}
Log.e("Debug", "Step11");
}
/*
This override method will Determine the state for the device , whether device is in range
of beacon or not , if yes then i = 1 and if no then i = 0
*/
@Override
public void didDetermineStateForRegion(int state, Region region) {
System.out.println("I have just switched from seeing/not seeing beacons: " + state);
}
});
//Specifies a class that should be called each time the BeaconService gets ranging data,
// which is nominally once per second when beacons are detected.
beaconManager.addRangeNotifier(new RangeNotifier() {
/*
This Override method tells us all the collections of beacons and their details that
are detected within the range by device
*/
@Override
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
// Checking if the Beacon inside the collection (ex. list) is there or not
// if Beacon is detected then size of collection is > 0
if (beacons.size() > 0) {
final ArrayList<ArrayList<String>> arrayList = new ArrayList<ArrayList<String>>();
BeaconManager.setRssiFilterImplClass(ArmaRssiFilter.class);
// Iterating through all Beacons from Collection of Beacons
ArrayList<Integer> arr = new ArrayList<Integer>();
int count = 0;
for (Beacon b : beacons) {
//RSSI
count += 1;
System.out.println(b.getBluetoothAddress()+" : "+b.getBluetoothName());
System.out.println("Count : " + count);
Integer rssi = Integer.valueOf(b.getRssi());
arr.add(rssi);
Integer maxRssi = Collections.max(arr);
for(Beacon b1 : beacons){
if(b1.getRssi() == maxRssi)
{
start = b1.getId1().toString();
maxid = start;
Log.e("Debug", "Step12");
System.out.println("uuid :"+func());
}
}
}
}
}
});
try {
//Tells the BeaconService to start looking for beacons that match the passed Region object.
beaconManager.startMonitoringBeaconsInRegion(region);
} catch (RemoteException e) {
}
}
@Override
public void onDestroy() {
super.onDestroy();
//Unbinds an Android Activity or Service to the BeaconService to avoid leak.
beaconManager.unbind(this);
finish();
}
首先设置出价。每当我退出该应用程序并再次重新打开它时，出价都不会改变。我必须清除该应用程序的数据，然后重新运行它才能正常工作。