以下是我使用相同方法的代码 - 一次在我onCreate()的{{1}}期间和用户点击一次按钮后的一次
MainActivity那为什么会这样呢？我基本上想要在加载应用程序时获取用户的当前位置，而不是强迫用户按下按钮以获得相同的内容。
// Below code not working during onCreate
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
// Create an instance of GoogleAPIClient. From Google API demo code
if (mGoogleApiClient == null) {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
startLocationOnScreen.setText(getCurrentLocationViaPhoneLocation());
// Surprisingly same method works if it's called after a button press!
startButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startLocationOnScreen.setText(getCurrentLocationViaPhoneLocation());
方法的实施 - （主要来自Google API文档）
getCurrentLocationViaPhoneLocation() 修改：我在protected String getCurrentLocationViaPhoneLocation() {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return "Error - location services not available!";
}
startLocation = LocationServices.FusedLocationApi.getLastLocation(
mGoogleApiClient);
if (startLocation != null) {
Log.e("We are at ", String.valueOf(startLocation.getLatitude()));
Log.e("We are at ", String.valueOf(startLocation.getLongitude()));
Geocoder geocoder = new Geocoder(this, Locale.getDefault());
try {
List<Address> addressList = geocoder.getFromLocation(startLocation.getLatitude(), startLocation.getLongitude(), 1);
if (addressList != null && addressList.size() > 0) {
currentCity = addressList.get(0).getLocality();
Address address = addressList.get(0);
StringBuilder sb = new StringBuilder();
for (int i = 0; i < address.getMaxAddressLineIndex(); i++) {
sb.append(address.getAddressLine(i)).append("\n");
}
return (sb.toString());
}
} catch (IOException e) {
e.printStackTrace();
}
}
return ("Error - current location unavailable!");
}
期间获得Error - current location unavailable!，这意味着在onCreate()期间调用该方法时startLocation==null。
答案 0 :(得分：1)
我怀疑在您第一次调用该方法时（即onCreate期间），GoogleApiClient尚未连接。
您已经调用了Builder的addConnectionCallbacks方法。因此，您应该在Activity中实施onConnected(Bundle) GoogleApiClient.ConnectionCallbacks方法。在此处调用getCurrentLocationViaPhoneLocation方法而不是onCreated，然后您可以确定GoogleApiClient已正确连接。
如果未调用onConnected方法，请在onCreate中创建实例后尝试添加mGoogleApiClient.connect()。
我希望有所帮助！