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私は緯度と経度を返すAndroidアプリを作成していますが、場所はNull値を保持しています。場所がNULLを返します
私はいつも私を悩まされている理由を見ることができるかどうか見てください。コード：
public class example extends Activity {
public static double latitude;
public static double longitude;
LocationManager lm;
LocationListener ll;
Location location;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.questions);
lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
ll = new MyLocationListener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
//location = lm.getLastKnownLocation(lm.getBestProvider(criteria, true));
Button b = (Button) findViewById(R.id.button2);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String provider = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
int index1 = provider.indexOf("gps");
if(index1 < 0)
// gps not enabled, call msgbox
showMsgBox("GPS is off", "GPS is off. Turn it on?", "Turn on");
else
areWeThereYet(); }});
}
private void areWeThereYet()
{
if(weAreThere())
{
toastMsg("in correct place");
}
else if(location!=null)
toastMsg("not there yet");
}
private boolean weAreThere() {
location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location!=null)
{
longitude = location.getLongitude();
latitude = location.getLatitude();
toastMsg(latitude + " " + longitude);
return inCorrectPlace(question);
}
else
{
toastMsg("Location not ready yet");
return false;
}
}
private void toastMsg(String msg) {
Toast toast = Toast.makeText(this, msg, 2000);
toast.setGravity(Gravity.BOTTOM, 0, 0);
toast.show();
}
}