I tried to extract value from inner method by global variable, but i cant access to any global variable from method, just i want to get the value from method to onCreate method!
Get value from inner method to another.
public class MainActivity extends AppCompatActivity {
FirebaseFirestore db;
//TextView txtv;
double tt = 55d;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = FirebaseFirestore.getInstance();
//txtv = (TextView) findViewById(R.id.txt);
//should print value of 'lat' >> 33
//but it print original value of tt >> 55
// I just want value of variable 'lat' here
System.out.println(ReadSingleContact(1));
}
public double ReadSingleContact(int x ) {
String num = Integer.toString(x);
DocumentReference contact = db.collection("MAPS").document(num);
contact.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task ) {
if(task.isSuccessful()){
DocumentSnapshot doc = task.getResult();
/*
StringBuilder data = new StringBuilder("");
data.append("name: ").append(doc.getString("name"));
data.append("\nlatitude: ").append(doc.getString("latitude"));
data.append("\nlongtude: ").append(doc.getString("longtude"));
*/
GeoPoint geoPoint = doc.getGeoPoint("latitude");
final double lat = geoPoint.getLatitude();
final double lng = geoPoint.getLongitude();
//let say lat = 33
tt = lat;
}
}
});
return tt;
}
}
no syntax error, just variable 'tt' dose not change ?
Edit - If you intent to use the function in multiple places and need to use the result, then you'll need to get the result from the asynchronous call using a callback (infact, you're already using a callback for contact.get()
). You'll need to refactor your code along the following lines.
Create a java file for the interface.
public interface CustomCallback {
void onComplete(double lat, double lng);
}
Use the interface as an argument to your function, call the onComplete
after you get the values of lat
& lng
.
public class MainActivity extends AppCompatActivity {
FirebaseFirestore db;
TextView txtv;
double tt ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = FirebaseFirestore.getInstance();
txtv = (TextView) findViewById(R.id.txt);
//txtv.setText(ReadSingleContact(1)+"A");
//Here you can call the function and implement the interface method that'll get called once the values for lat & lng are calculated
ReadSingleContact(1, new CustomCallback() {
@Override
public void onComplete(double lat, double lng) {
//here you can implement your required code
//which can be changed based on what calls this method
txtv.setText(lat+"A");
//P.S - At this point, the value of tt would have been changed, since the `onComplete` method gets called after the value of tt is changed.
}
});
}
public void ReadSingleContact(int x, CustomCallback customCallback) {
String num = Integer.toString(x);
DocumentReference contact = db.collection("MAPS").document(num);
contact.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task ) {
if(task.isSuccessful()){
DocumentSnapshot doc = task.getResult();
/*
StringBuilder data = new StringBuilder("");
data.append("name: ").append(doc.getString("name"));
data.append("\nlatitude: ").append(doc.getString("latitude"));
data.append("\nlongtude: ").append(doc.getString("longtude"));
*/
GeoPoint geoPoint = doc.getGeoPoint("latitude");
double lat = geoPoint.getLatitude();
double lng = geoPoint.getLongitude();
tt = 22;
//Call customCallback.onComplete at the end
if (customCallback != null) {
customCallback.onComplete(lat,lng);
}
}
}
});
}
}
The contact.get()
is an asynchronous call, so tt = 22;
will likely only occur after return tt;
. If you simply want to set the latitude and longitude value in the textview, then do so in the callback.
public class MainActivity extends AppCompatActivity {
FirebaseFirestore db;
TextView txtv;
double tt ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = FirebaseFirestore.getInstance();
txtv = (TextView) findViewById(R.id.txt);
//txtv.setText(ReadSingleContact(1)+"A");
}
public double ReadSingleContact(int x ) {
String num = Integer.toString(x);
DocumentReference contact = db.collection("MAPS").document(num);
contact.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task ) {
if(task.isSuccessful()){
DocumentSnapshot doc = task.getResult();
/*
StringBuilder data = new StringBuilder("");
data.append("name: ").append(doc.getString("name"));
data.append("\nlatitude: ").append(doc.getString("latitude"));
data.append("\nlongtude: ").append(doc.getString("longtude"));
*/
GeoPoint geoPoint = doc.getGeoPoint("latitude");
double lat = geoPoint.getLatitude();
double lng = geoPoint.getLongitude();
//value dose not changed ??!
tt = 22;
runOnUiThread(new Runnable() {
void run() {
txtv.setText(tt+"A");
txtv.setText(lat+","+lng);
}
});
}
}
});
return tt;
}
}
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