访问经纬度 Android Google API

Question

我正在制作一个能够访问并使用用户的纬度和经度来显示附近餐馆的应用。

我试图从 onConnected(Bundle bunle) 方法中检索纬度和经度变量，如下所示，以便在 onCreate() 方法中访问和使用它们，但是我在顶部声明的字符串纬度不会存储当我将其设置为等于 onConnnected() 方法上的用户纬度时的纬度值。当我在 toast 消息上显示字符串时，我尝试测试结果是什么，但 toast 只是空白，表明字符串尚未设置为等于纬度值。但是，如果我尝试在 onConnected() 方法的范围内显示 toast，它会起作用。但我确实需要在 onConnected() 方法之外的 onCreate() 方法中访问这个纬度和经度。

我已经发布了下面的代码！任何帮助将不胜感激！

    public class MainActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener, GoogleApiClient.ConnectionCallbacks, com.google.android.gms.location.LocationListener {

protected static final String TAG = "Gokul Log Message: ";
protected GoogleApiClient mGoogleApiClient;
protected Location mLastLocation;
protected TextView textLatitude;
public String mLat = null;

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

    textLatitude = (TextView)this.findViewById(R.id.textLatitude);

    Toast.makeText(MainActivity.this, mLat, Toast.LENGTH_LONG).show();

    buildGoogleApiClient();

}

protected synchronized void buildGoogleApiClient(){
    Log.v("Log1", "Entering buildGoogleApiClient method");

    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();
}
@Override
protected void onStart(){
    Log.v("Log1", "Entering onStart() method");

    super.onStart();
    mGoogleApiClient.connect();
}
@Override
protected void onStop(){
    Log.v("Log1", "Entering onStop() method");

    super.onStop();
    if (mGoogleApiClient.isConnected()){
        mGoogleApiClient.disconnect();
    }
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;

}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@Override
public void onConnected(Bundle bundle) {
    Log.v("Log1", "Entering onConnected() method");


    mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
    if (mLastLocation != null){
        textLatitude.setText(String.valueOf(mLastLocation.getLatitude()));
       //textLongitude.setText(String.valueOf(mLastLocation.getLongitude()));
        mLat = String.valueOf(mLastLocation.getLatitude());
        Log.v("Log1onConnected", mLat + "asd");
    }

    Log.v("Log1onConnected2", mLat + "asd");

}

@Override
public void onConnectionSuspended(int i) {


    Log.i(TAG, "Connection suspended");
    mGoogleApiClient.connect();

}

@Override
public void onLocationChanged(Location location) {

}

@Override
public void onConnectionFailed(ConnectionResult connectionResult) {

    Log.i(TAG, "Connection failed: " + connectionResult.getErrorCode());

}

}

Answer 1

它没有改变，因为它还没有位置。仅仅因为您连接到 google play 并不意味着位置已准备好。您需要监听位置更新并在 onLocationChanged 中设置值。