android：即使在启用 GPS 后也无法使用 FusedLocationApi 找到位置

Question

我正在尝试使用 GPS 和 FusedLocationApi 位置查找手机的位置。即使在启用 GPS 后，我也没有获得位置详细信息。以下是我遵循的步骤。请帮助我。

第一步：-

在我的 gradle

中添加了行

  compile 'com.google.android.gms:play-services-location:8.1.0'

第 2 步：-

MainActivity 文件

package com.developer.kamalasekar.locationfinder;

import android.location.Location;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;

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

   private static final String TAG = "MainActivity";
    private TextView mLatitudeTextView;
    private TextView mLongitudeTextView;
    private GoogleApiClient mGoogleApiClient;
    private Location mLocation;
    private LocationRequest mLocationRequest;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mLatitudeTextView = (TextView) findViewById((R.id.latitude_textview));
        mLongitudeTextView = (TextView) findViewById((R.id.longitude_textview));

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

    @Override
    public void onConnected(Bundle bundle) {
        mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

        if (mLocation != null) {
            mLatitudeTextView.setText(String.valueOf(mLocation.getLatitude()));
            mLongitudeTextView.setText(String.valueOf(mLocation.getLongitude()));
        } else {
            Toast.makeText(this, "Location not Detected", Toast.LENGTH_SHORT).show();
        }
      LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);




    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.i(TAG, "Connection Suspended");
        mGoogleApiClient.connect();
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.i(TAG, "Connection failed. Error: " + connectionResult.getErrorCode());
    }

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

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

第三步：-

ActivityMain

<?xml version="1.0" encoding="utf-8"?>
<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">

    <TextView
        android:id="@+id/latitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="Latitude:"
        android:textSize="18sp" />
    <TextView
        android:id="@+id/latitude_textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/latitude"
        android:layout_marginLeft="10dp"
        android:layout_toRightOf="@+id/latitude"
        android:textSize="16sp" />
    <TextView
        android:id="@+id/longitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="Longitude:"
        android:layout_marginTop="24dp"
        android:textSize="18sp" />
    <TextView
        android:id="@+id/longitude_textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/longitude"
        android:layout_marginLeft="10dp"
        android:layout_toRightOf="@+id/longitude"
        android:textSize="16sp"/>

</RelativeLayout>

第 4 步：- 在我的清单文件中添加了这些行

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.developer.kamalasekar.locationfinder">


    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

       </application>

</manifest>

Answer 1

在 onConnected 中，如果您调用 LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient); 可能会在找不到位置时 return 为空。但是，如果您在几秒后再次执行同一行 （1/2 秒并启用了 gps） 那么您肯定可以确定位置。

@Override
public void onConnected(Bundle bundle) {
    mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
    if (mLocation != null) {
        //your stuff
    } else {
        handler.sendEmptyMessageDelayed(1, 2000);
    }
}

int count;
android.os.Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        if (count < 2) {
            mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
            if (mLocation == null){
                handler.sendEmptyMessageDelayed(1, 2000);
            }else{
                 //your stuff
            }
            count++;
        } else{
            Log.i("MyTag","location not found");
        }
    }
};

或访问Android: Location Updates with the FusedLocationApi
或者您可以通过设置 LocationListener 来关注@user2450263 post。

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