Android:电子邮件使用率低的Google地图位置

Question

我的应用目前正在使用Google地图 Google Play Services

speficying:

mMap.setMyLocationEnabled(true);

每当我在我的应用程序中显示地图时,我都会意识到:

• 该位置在地图上以蓝点表示
• 顶部栏中显示位置图标
• 如果我进入手机的设置/位置,我的应用报告为"高电量使用"

但是,我可以看到有些应用程序使用地图并仍然显示位置蓝点,但位置图标不会出现在顶部栏中,并且它们的电池使用率很低.

我的应用目前授予两种权限:

• android.permission.ACCESS_COARSE_LOCATION
• android.permission.ACCESS_FINE_LOCATION

我的问题是:

如何在电池使用率低的情况下显示蓝点位置？

是否可以通过代码指定准确度/电池使用情况？

UPDATE

实际上我意识到这样做的方法是使用GoogleApiClient'sFusedLocationApi

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

我在我的Activity中配置了GoogleApiClient,调用:

• GoogleApiClient.connect() 在活动的开始
• GoogleApiClient.disconnect() 在活动的停止

在onConnected回调中,我设置了位置更新的标准:1分钟的最快间隔,具有低功率优先级:

    private static final LocationRequest REQUEST = LocationRequest.create()
        .setFastestInterval(60000)   // in milliseconds
        .setInterval(180000)         // in milliseconds
        .setPriority(LocationRequest.PRIORITY_LOW_POWER);

    @Override
    public void onConnected(Bundle bundle) {
        LocationServices.FusedLocationApi.requestLocationUpdates(
            mGoogleApiClient,
            REQUEST,
            this);  // LocationListener
    }

我已经测试了GoogleApiClient在开始时正确连接,但出于某些原因,每当我使用嵌入式MapView访问片段时,我仍然可以在设置/位置屏幕上为我的应用程序获得高电量!

似乎MapView忽略了这些低功耗标准!

Answer 1

最终找到了解决方案! 感谢特里斯坦的回答!

默认情况下,GoogleMap使用其位置提供程序,而不是融合位置提供程序.为了使用融合位置提供程序(允许您控制位置精度和功耗),您需要明确设置地图位置源GoogleMap.setLocationSource()(文档)

我在这里报告了一个样本活动:

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMyLocationButtonClickListener;
import com.google.android.gms.maps.LocationSource;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;

import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends FragmentActivity
    implements
        ConnectionCallbacks,
        OnConnectionFailedListener,
        LocationSource,
        LocationListener,
        OnMyLocationButtonClickListener,
        OnMapReadyCallback {

    private GoogleApiClient mGoogleApiClient;
    private TextView mMessageView;
    private OnLocationChangedListener mMapLocationListener = null;

    // location accuracy settings
    private static final LocationRequest REQUEST = LocationRequest.create()
            .setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mMessageView = (TextView) findViewById(R.id.message_text);

        SupportMapFragment mapFragment =
                (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

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

    }

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

    @Override
    public void onPause() {
        super.onPause();
        mGoogleApiClient.disconnect();
    }

    @Override
    public void onMapReady(GoogleMap map) {
        map.setLocationSource(this);
        map.setMyLocationEnabled(true);
        map.setOnMyLocationButtonClickListener(this);
    }

    public void showMyLocation(View view) {
        if (mGoogleApiClient.isConnected()) {
            String msg = "Location = "
                    + LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
            Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_SHORT).show();
        }
    }

    /**
     * Implementation of {@link LocationListener}.
     */
    @Override
    public void onLocationChanged(Location location) {
        mMessageView.setText("Location = " + location);
        if (mMapLocationListener != null) {
            mMapLocationListener.onLocationChanged(location);
        }
    }


    @Override
    public void onConnected(Bundle connectionHint) {
        LocationServices.FusedLocationApi.requestLocationUpdates(
                mGoogleApiClient,
                REQUEST,
                this);  // LocationListener
    }


    @Override
    public void onConnectionSuspended(int cause) {
        // Do nothing
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
        // Do nothing
    }

    @Override
    public boolean onMyLocationButtonClick() {
        Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show();
        // Return false so that we don't consume the event and the default behavior still occurs
        // (the camera animates to the user's current position).
        return false;
    }

    @Override
    public void activate(OnLocationChangedListener onLocationChangedListener) {
        mMapLocationListener = onLocationChangedListener;
    }

    @Override
    public void deactivate() {
        mMapLocationListener = null;
    }
}

Answer 2

您将希望使您的活动(或更好地为此目的的单独对象)实现该LocationSource接口.

很简单,您需要存储activate()方法中传递的侦听器,并在更新位置时调用它,并在调用时忘记它deactivate().有关示例,请参阅此答案,您可能希望更新它以使用FusedLocationProvider.

完成此设置后,您可以将活动作为LocationSource地图传递,如此mMap.setLocationSource(this)(文档).

这将阻止地图使用其LocationSource使用高电池使用位置服务的默认值.