位置更改时 XML 数据不更新

Question

我正在构建一个应用程序，该应用程序会在屏幕上显示某些更新信息后。我已经为 XML 和 Java 添加了代码，如果有人能告诉我文本视图和 Java 代码是否正确，我将不胜感激。

XML

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity" android:padding="0dp">
  <ImageView android:layout_width="fill_parent" android:layout_height="fill_parent" android:id="@+id/imageView" android:layout_alignParentTop="true" android:layout_alignParentStart="true" android:src="@drawable/background" android:scaleType="centerCrop" /> 
  <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hiker's Watch" android:id="@+id/textView" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:textSize="30sp" android:textColor="#f3202020" android:layout_marginTop="30dp" /> 

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Latitude: " android:id="@+id/lat" android:layout_below="@+id/textView" android:layout_centerHorizontal="true" android:layout_marginTop="30dp" android:textSize="20sp" android:textColor="#151515" /> 

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Longitude:" android:id="@+id/lng" android:layout_below="@+id/lat" android:layout_centerHorizontal="true" android:layout_marginTop="10dp" android:textSize="20sp" android:textColor="#151515" /> 
  <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Accuracy: 20.0m" android:id="@+id/accuracy" android:layout_below="@+id/lng" android:layout_centerHorizontal="true" android:layout_marginTop="10dp" android:textSize="20sp" android:textColor="#151515" /> 

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Speed:" android:id="@+id/speed" android:layout_below="@+id/accuracy" android:layout_centerHorizontal="true" android:layout_marginTop="20dp" android:textSize="20sp" android:textColor="#151515" /> 

 <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Bearing: " android:id="@+id/bearing" android:layout_below="@+id/speed" android:layout_centerHorizontal="true" android:layout_marginTop="10dp" android:textSize="20sp" android:textColor="#151515" /> 

 <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Altitude:" android:id="@+id/altitude" android:layout_below="@+id/bearing" android:layout_centerHorizontal="true" android:layout_marginTop="20dp" android:textSize="20sp" android:textColor="#151515" /> 

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Address: \n" android:id="@+id/address" android:layout_below="@+id/altitude" android:layout_centerHorizontal="true" android:layout_marginTop="20dp" android:textSize="20sp" android:textColor="#151515" android:gravity="center_horizontal" /> 

 </RelativeLayout>

Java

import android.app.Activity;
import android.content.Context;
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

import java.io.IOException;
import java.util.List;
import java.util.Locale;

public class MainActivity extends Activity implements LocationListener {

    LocationManager locationManager;
    String provider;

    TextView latTV;
    TextView lngTV;
    TextView accuracyTV;
    TextView speedTV;
    TextView bearingTV;
    TextView altitudeTV;
    TextView addressTV;

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

        latTV = (TextView) findViewById(R.id.lat);
        lngTV = (TextView) findViewById(R.id.lng);
        accuracyTV = (TextView) findViewById(R.id.accuracy);
        speedTV = (TextView) findViewById(R.id.speed);
        bearingTV = (TextView) findViewById(R.id.bearing);
        altitudeTV = (TextView) findViewById(R.id.altitude);
        addressTV = (TextView) findViewById(R.id.address);


        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        provider = locationManager.getBestProvider(new Criteria(), false);

        Location location = locationManager.getLastKnownLocation(provider);

        onLocationChanged(location);



    }

    @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
    protected void onPause() {
        super.onPause();

        locationManager.removeUpdates(this);

    }

    @Override
    protected void onResume() {
        super.onResume();

        locationManager.requestLocationUpdates(provider, 400, 1, this);

    }

    @Override
    public void onLocationChanged(Location location) {

        Double lat = location.getLatitude();
        Double lng = location.getLongitude();
        Double alt = location.getAltitude();
        Float bearing = location.getBearing();
        Float speed = location.getSpeed();
        Float accuracy = location.getAccuracy();

        Geocoder geocoder = new Geocoder(getApplicationContext(), Locale.getDefault());

        try {
            List<Address> listAddresses = geocoder.getFromLocation(lat, lng, 1);

            if (listAddresses != null && listAddresses.size() > 0 ) {

                Log.i("PlaceInfo", listAddresses.get(0).toString());

                String addressHolder = "";

                for (int i = 0; i <= listAddresses.get(0).getMaxAddressLineIndex(); i++) {

                    addressHolder += listAddresses.get(0).getAddressLine(i) + "\n";

                }

                addressTV.setText("Address:\n" + addressHolder);

            }

        } catch (IOException e) {
            e.printStackTrace();
        }

        latTV.setText("Latitude: " + lat.toString());
        lngTV.setText("Longitude: " + lng.toString());
        altitudeTV.setText("Altitude: " + alt.toString() + "m");
        bearingTV.setText("Bearing: " + bearing.toString());
        speedTV.setText("Speed: " + speed.toString() + "m/s");
        accuracyTV.setText("Accuracy: " + accuracy.toString() + "m");



    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
}

Answer 1

您对Double 和Float 的String 解析在.setText(); 内部不正确。

更正：

latTV.setText("Latitude: " + String.valueOf(lat));
lngTV.setText("Longitude: " + String.valueOf(lng));
altitudeTV.setText("Altitude: " + String.valueOf(alt) + "m");
bearingTV.setText("Bearing: " + Float.toString(bearing));
speedTV.setText("Speed: " + Float.toString(speed) + "m/s");
accuracyTV.setText("Accuracy: " + Float.toString(accuracy) + "m");

Answer 2

你应该使用Fused location api

    public class MainActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {


    TextView txtOutputLat, txtOutputLon;
    Location mLastLocation;
    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;
    String lat, lon;


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


        txtOutputLat = (TextView) findViewById(R.id.textView);
        txtOutputLon = (TextView) findViewById(R.id.textView2);


        buildGoogleApiClient();
    }


    @Override
    public void onConnected(Bundle bundle) {


        mLocationRequest = LocationRequest.create();
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        mLocationRequest.setInterval(100); // Update location every second

        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);


        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);
        if (mLastLocation != null) {
            lat = String.valueOf(mLastLocation.getLatitude());
            lon = String.valueOf(mLastLocation.getLongitude());

        }
        updateUI();
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onLocationChanged(Location location) {
        lat = String.valueOf(location.getLatitude());
        lon = String.valueOf(location.getLongitude());
        //get other relevant data from location like bearing,address
        updateUI();
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        buildGoogleApiClient();
    }

    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 onDestroy() {
        super.onDestroy();
        mGoogleApiClient.disconnect();
    }

    void updateUI() {
        txtOutputLat.setText(lat);
        txtOutputLon.setText(lon);
    }
}

这是一个详细的例子：http://www.androidwarriors.com/2015/10/fused-location-provider-in-android.html

Fused location provider API 的最大优点是您无需担心location 的更新，它始终为您提供最新且准确的location，并在一段时间后或location 更改后更新location。

关于Fused location provider API 的另一件事是您无需考虑最佳location 提供商，因为它会自动选择最适合您的Android 设备硬件的提供商。