我遇到一个问题，即每10秒更新一次我的位置。我也想在Firebase上存储我的起始位置....我无法理解如何存储起始点，因为Firebase正在更新...这是我的代码
i am having an issue that i am updating my location after every 10 sec. i want to store my starting position as well on firebase .... i cant understand how to store the starting point because the firebase is updating ... here is my code
我遇到一个问题，即每10秒更新一次我的位置。我也想在Firebase上存储我的起始位置....我无法理解如何存储起始点，因为Firebase正在更新...这是我的代码
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.app.Activity;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.iid.FirebaseInstanceId;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
public class Location_activity extends Activity implements LocationListener , ScheduledExecutorService{
private TextView latituteField, longitudeField;
private LocationManager lm;
private String provider;
private Button startbtn , cancelbtn;
DatabaseReference mDatabaseref;
FirebaseUser current_user;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_location_activity);
latituteField = (TextView) findViewById(R.id.TextView02);
longitudeField = (TextView) findViewById(R.id.TextView04);
startbtn = (Button) findViewById(R.id.btn_start);
cancelbtn = (Button) findViewById(R.id.btn_cancel);
startbtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final ScheduledExecutorService scheduleTaskExecutor = Executors.newScheduledThreadPool(5);
scheduleTaskExecutor.scheduleAtFixedRate(new Runnable() {
public void run() {
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Location myLocation = null;
if (lm != null) {
if (ActivityCompat.checkSelfPermission(Location_activity.this,
android.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(Location_activity.this,
android.Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
return;
}
myLocation = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (myLocation == null) {
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_COARSE);
String provider = lm.getBestProvider(criteria, true);
myLocation = lm.getLastKnownLocation(provider);
}
if (myLocation == null) {
myLocation = lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
}
if (myLocation != null){
System.out.println("Provider " + provider + " has been selected.");
onLocationChanged(myLocation);
}
}
}
}, 1, 10, TimeUnit.SECONDS);
cancelbtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
scheduleTaskExecutor.shutdown();
}
});
}
});
}
@Override
protected void onResume() {
super.onResume();
}
@Override
protected void onPause() {
super.onPause();
lm.removeUpdates(this);
}
@Override
public void onLocationChanged(Location location) {
double lat = (double) (location.getLatitude());
double lng = (double) (location.getLongitude());
current_user = FirebaseAuth.getInstance().getCurrentUser();
String uid = current_user.getUid();
mDatabaseref = FirebaseDatabase.getInstance().getReference().child("location").child(uid);
String device_token = FirebaseInstanceId.getInstance().getToken();
HashMap<String, String> userMap = new HashMap<>();
userMap.put("latitude", String.valueOf(lat));
userMap.put("longitude" , String.valueOf(lng));
userMap.put("device_token", device_token);
mDatabaseref.setValue(userMap).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Toast.makeText(getApplicationContext() , "Location updated" , Toast.LENGTH_SHORT ).show();
}
});
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
Toast.makeText(this, "Enabled new provider " + provider,
Toast.LENGTH_SHORT).show();
}
@Override
public void onProviderDisabled(String provider) {
Toast.makeText(this, "Disabled provider " + provider,
Toast.LENGTH_SHORT).show();
}
@NonNull
@Override
public ScheduledFuture<?> schedule(@NonNull Runnable command, long delay, @NonNull TimeUnit unit) {
return null;
}
@NonNull
@Override
public <V> ScheduledFuture<V> schedule(@NonNull Callable<V> callable, long delay, @NonNull TimeUnit unit) {
return null;
}
@NonNull
@Override
public ScheduledFuture<?> scheduleAtFixedRate(@NonNull Runnable command, long initialDelay, long period, @NonNull TimeUnit unit) {
return null;
}
@NonNull
@Override
public ScheduledFuture<?> scheduleWithFixedDelay(@NonNull Runnable command, long initialDelay, long delay, @NonNull TimeUnit unit) {
return null;
}
@Override
public void shutdown() {
}
@NonNull
@Override
public List<Runnable> shutdownNow() {
return null;
}
@Override
public boolean isShutdown() {
return false;
}
@Override
public boolean isTerminated() {
return false;
}
@Override
public boolean awaitTermination(long timeout, @NonNull TimeUnit unit) throws InterruptedException {
return false;
}
@NonNull
@Override
public <T> Future<T> submit(@NonNull Callable<T> task) {
return null;
}
@NonNull
@Override
public <T> Future<T> submit(@NonNull Runnable task, T result) {
return null;
}
@NonNull
@Override
public Future<?> submit(@NonNull Runnable task) {
return null;
}
@NonNull
@Override
public <T> List<Future<T>> invokeAll(@NonNull Collection<? extends Callable<T>> tasks) throws InterruptedException {
return null;
}
@NonNull
@Override
public <T> List<Future<T>> invokeAll(@NonNull Collection<? extends Callable<T>> tasks, long timeout, @NonNull TimeUnit unit) throws InterruptedException {
return null;
}
@NonNull
@Override
public <T> T invokeAny(@NonNull Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {
return null;
}
@Override
public <T> T invokeAny(@NonNull Collection<? extends Callable<T>> tasks, long timeout, @NonNull TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
return null;
}
@Override
public void execute(@NonNull Runnable command) {
}
}
答案 0 :(得分：0)
int i = 0;
mDatabaseref = FirebaseDatabase.getInstance().getReference().child("location").child(uid);
String device_token = FirebaseInstanceId.getInstance().getToken();
HashMap<String, String> userMap = new HashMap<>();
userMap.put("Startlatitude", String.valueOf(lat));
userMap.put("Startlongitude" , String.valueOf(lng));
userMap.put("Currentlatitude" , String.valueOf(lat));
userMap.put("Currentlongitude" , String.valueOf(lng));
if(i==0) {
userMap.put("device_token", device_token);
mDatabaseref.setValue(userMap).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Toast.makeText(getApplicationContext() , "Location updated" , Toast.LENGTH_SHORT ).show();
i++;
}
});
}
else {
userMap.child("Currentlatitude").setValue(String.valueOf(lat));
userMap.child("Currentlongitude").setValue(String.valueOf(lng));
// Attach addOnCompleteListener
// You can also use HashMap to update both together.
}
因此，只有第一次纬度和经度会保存在数据库中，因为最初i = 0。当开始lat时，将保存多长时间，i会增加。因此，从下一次开始，其他条件永远都是正确的。我希望这能完成您的工作。
答案 1 :(得分：0)
之所以发生这种情况，是因为您在位置上添加了一个侦听器，并且每次位置更改时，都会得到一个新的services.AddIdentity<IdentityUser, IdentityRole>()对象，该对象包含新坐标，并且每次将这些新坐标写入数据库中。如果只想将起点写入数据库，则应声明一个名为.AddDefaultTokenProviders()的布尔值，默认值为false。
Location然后只需编写如下条件：
isStartingPointWritten通过这种方式，您可以将写入操作限制为仅发生一次。