[英]Trouble calling and getting location in oncreate method from location listener android
我需要你關於android中位置更新的幫助。 以下是我獲取位置更新的代碼,它運行正常。 但是當我在主類的oncreate方法中獲取帶位置的存儲變量時,它返回無效的消息體。 經過深入研究后,似乎我在oncreate方法中調用的變量是空的。 您能告訴我如何獲取onlocationChanged方法中顯示的地址。 謝謝!
使用oncreate方法調用類:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listener = new Mylocation();
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, listener);
String address1= listener.getAddress();
{
sendSms(phone, message, false);
} catch (Exception e) {
Log.i("Error Is ", e.toString());
}
}
位置等級:
class Mylocation implements LocationListener{
double lat, lon;
static final String address="";
public void onLocationChanged(Location location)
{
//...
lat = location.getLatitude();
lon = location.getLongitude();
address = GetAddressDetail(lat, lon);
Log.i("Messge is", address); //working here
}
public String getAddress(){ //not returning the address
return address;
}
public String GetAddressDetail(Double lat2, Double lon2)
{
Geocoder geocoder = new Geocoder(MainActivity.this, Locale.ENGLISH);
try {
List<Address> addresses = geocoder.getFromLocation(lat2,lon2, 1);
if(addresses != null) {
Address returnedAddress = addresses.get(0);
StringBuilder strReturnedAddress = new StringBuilder("Address:");
for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
strReturnedAddress.append(returnedAddress.getAddressLine(i));
}
ret = strReturnedAddress.toString();
}
else{
ret = "No Address returned!";
}
}
return ret;
}
}
確保您的變量已正確初始化。 我在問題中沒有看到這方面的證據所以我只是在檢查。
// Instantiation
Mylocation listener;
String phone;
String message;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Initialization
listener = new Mylocation(this);
phone = "";
message = "";
// These two lines aren't really necessary,
// this should be in your MyLocation class
//locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
//locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, listener);
// Add this line, we are going to initialize this class
// and make sure that address gets set
listener = new Mylocation();
String address1 = listener.getAddress();
try {
// If neither phone nor message is empty lets sendSms()
if (!phone.isEmpty() || !message.isEmpty()) {
sendSms(phone, message, false);
}
} catch (Exception e) {
Log.i("Error Is ", e.toString());
}
}
將String address
更改為private並在getter中嘗試return this.address;
class Mylocation implements LocationListener {
double lat, lon;
// Let's make this private so it can't be accessed directly,
// since you have the setter and getter.
private String address = "";
// Make sure you are overriding this method
@Override
public void onLocationChanged(Location location) {
/** ... */
lat = location.getLatitude();
lon = location.getLongitude();
address = GetAddressDetail(lat, lon);
Log.i("Messge is", address);
}
public String getAddress(){
return (address.isEmpty()) ? "Address not set" : this.address;
}
public String GetAddressDetail(Double lat2, Double lon2) {
Geocoder geocoder = new Geocoder(MainActivity.this, Locale.ENGLISH);
try {
List<Address> addresses = geocoder.getFromLocation(lat2,lon2, 1);
if(addresses != null) {
Address returnedAddress = addresses.get(0);
StringBuilder strReturnedAddress = new StringBuilder("Address:");
for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
strReturnedAddress.append(returnedAddress.getAddressLine(i));
}
ret = strReturnedAddress.toString();
}
else{
ret = "No Address returned!";
}
}
return ret;
}
}
編輯
我在上面的答案中對您的代碼進行了更改,請查看注釋。 我還將為您的MyLocation
類建議其他方法:
class Mylocation implements LocationListener {
protected LocationManager locationManager;
private Context activityContext;
// The initializing method, this fires off first
// when a new instance of the class is created
public MyLocation(Context context) {
this.activityContext = context;
locationManager = (LocationManager) activityContext.getSystemService(LOCATION_SERVICE);
if (locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);) {
locationManager.requestLocationUpdates(
NETWORK_PROVIDER,
MIN_TIME,
MIN_DISTANCE,
this
);
}
getLocation();
}
private double lat;
private double lon;
public double getLat() {
return this.lat;
}
public double getLng() {
return this.lng;
}
public void getLocation() {
if (location == null) {
locationManager.requestLocationUpdates(NETWORK_PROVIDER, MIN_TIME, MIN_DISTANCE, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(NETWORK_PROVIDER);
if (location != null) {
// Set the coordinate variables
lat = location.getLatitude();
lon = location.getLongitude();
Log.i("Network", "Lat: " + latitude + " / Lng: " + longitude);
}
}
}
}
}
在將locationmanager設置為探測位置后,您將直接調用getAdress。 當您以這種方式調用getAddress時,可能還沒有調用onLocationChanged方法。 我建議將其更改為類似下面的內容,以確保它已被調用:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listener = new Mylocation();
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,new LocationListener(){
@Override
public void onLocationChanged(Location location) {
//...
long lat = location.getLatitude();
long lon = location.getLongitude();
String address = GetAddressDetail(lat, lon);
//Do whatever you want to do with the address here, maybe add them to the message or something like that.
sendSms(phone, message, false);
}
});
}
public String GetAddressDetail(Double lat2, Double lon2)
{
Geocoder geocoder = new Geocoder(MainActivity.this, Locale.ENGLISH);
try {
List<Address> addresses = geocoder.getFromLocation(lat2,lon2, 1);
if(addresses != null) {
Address returnedAddress = addresses.get(0);
StringBuilder strReturnedAddress = new StringBuilder("Address:");
for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
strReturnedAddress.append(returnedAddress.getAddressLine(i));
}
ret = strReturnedAddress.toString();
}
else{
ret = "No Address returned!";
}
}
return ret;
}
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