java - 如何在获取最后位置时解决 mLastLocation、mLatitudeText、mLongitudeText

Question

我目前正在尝试按照本教程获取 Android 设备的最后位置 - https://developer.android.com/training/location/retrieve-current.html#play-services - 但我无法通过最后一部分。

我的代码:

package com.example.prouser.driveapp;


public class MainActivity extends AppCompatActivity implements ConnectionCallbacks {


/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
private GoogleApiClient client;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    super.onStart();

protected void onStart() {
    mGoogleApiClient.connect();
    super.onStart();
}

protected void onStop() {
    mGoogleApiClient.disconnect();
    super.onStop();
}

public void onConnected(Bundle connectionHint) {

    if (mLastLocation != null) {
        mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
        mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
    }
}


// Create an instance of GoogleAPIClient.
GoogleApiClient mGoogleApiClient = new GoogleApiClient() {
    @Override
    public boolean hasConnectedApi(@NonNull Api<?> api) {
        return false;
    }

    @NonNull
    @Override
    public ConnectionResult getConnectionResult(@NonNull Api<?> api) {
        return null;
    }

    @Override
    public void connect() {

    }

    @Override
    public ConnectionResult blockingConnect() {
        return null;
    }

    @Override
    public ConnectionResult blockingConnect(long l, @NonNull TimeUnit timeUnit) {
        return null;
    }

    @Override
    public void disconnect() {

    }

    @Override
    public void reconnect() {

    }

    @Override
    public PendingResult<Status> clearDefaultAccountAndReconnect() {
        return null;
    }

    @Override
    public void stopAutoManage(@NonNull FragmentActivity fragmentActivity) {

    }

    @Override
    public boolean isConnected() {
        return false;
    }

    @Override
    public boolean isConnecting() {
        return false;
    }

    @Override
    public void registerConnectionCallbacks(@NonNull ConnectionCallbacks connectionCallbacks) {

    }

    @Override
    public boolean isConnectionCallbacksRegistered(@NonNull ConnectionCallbacks connectionCallbacks) {
        return false;
    }

    @Override
    public void unregisterConnectionCallbacks(@NonNull ConnectionCallbacks connectionCallbacks) {

    }

    @Override
    public void registerConnectionFailedListener(@NonNull OnConnectionFailedListener onConnectionFailedListener) {

    }

    @Override
    public boolean isConnectionFailedListenerRegistered(@NonNull OnConnectionFailedListener onConnectionFailedListener) {
        return false;
    }

    @Override
    public void unregisterConnectionFailedListener(@NonNull OnConnectionFailedListener onConnectionFailedListener) {

    }

    @Override
    public void dump(String s, FileDescriptor fileDescriptor, PrintWriter printWriter, String[] strings) {

    }
};
if(mGoogleApiClient==null)

{
    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener((OnConnectionFailedListener) this)
            .addApi(LocationServices.API)
            .build();
}
}

@Override
public void onConnected(@Nullable Bundle bundle) {

}

@Override
public void onConnectionSuspended(int i) {


}

Answer 1

试试这个:

public class MainActivity extends AppCompatActivity implements
        ConnectionCallbacks, OnConnectionFailedListener {

    protected static final String TAG = "MainActivity";

    /**
     * Provides the entry point to Google Play services.
     */
    protected GoogleApiClient mGoogleApiClient;

    /**
     * Represents a geographical location.
     */
    protected Location mLastLocation;

    protected String mLatitudeLabel;
    protected String mLongitudeLabel;
    protected TextView mLatitudeText;
    protected TextView mLongitudeText;



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);

        mLatitudeLabel = getResources().getString(R.string.latitude_label);
        mLongitudeLabel = getResources().getString(R.string.longitude_label);
        mLatitudeText = (TextView) findViewById((R.id.latitude_text));
        mLongitudeText = (TextView) findViewById((R.id.longitude_text));

        buildGoogleApiClient();
    }

    /**
     * Builds a GoogleApiClient. Uses the addApi() method to request the LocationServices API.
     */
    protected synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (mGoogleApiClient.isConnected()) {
            mGoogleApiClient.disconnect();
        }
    }

    /**
     * Runs when a GoogleApiClient object successfully connects.
     */
    @Override
    public void onConnected(Bundle connectionHint) {
        // Provides a simple way of getting a device's location and is well suited for
        // applications that do not require a fine-grained location and that do not need location
        // updates. Gets the best and most recent location currently available, which may be null
        // in rare cases when a location is not available.
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (mLastLocation != null) {
            mLatitudeText.setText(String.format("%s: %f", mLatitudeLabel,
                    mLastLocation.getLatitude()));
            mLongitudeText.setText(String.format("%s: %f", mLongitudeLabel,
                    mLastLocation.getLongitude()));
        } else {
            Toast.makeText(this, R.string.no_location_detected, Toast.LENGTH_LONG).show();
        }
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
        // Refer to the javadoc for ConnectionResult to see what error codes might be returned in
        // onConnectionFailed.
        Log.i(TAG, "Connection failed: ConnectionResult.getErrorCode() = " + result.getErrorCode());
    }


    @Override
    public void onConnectionSuspended(int cause) {
        // The connection to Google Play services was lost for some reason. We call connect() to
        // attempt to re-establish the connection.
        Log.i(TAG, "Connection suspended");
        mGoogleApiClient.connect();
    }
}

这里有一个完整的示例:

https://github.com/googlesamples/android-play-location