百度地图API android studio中不显示地图只显示网格线的问题

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

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.CALL_PHONE"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="ACCESS_MOCK_LOCATION"/>
<uses-permission android:name="ACCESS_GPS"/>

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>

<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<meta-data
android:name="com.baidu.lbsapi.API_KEY"
android:value="uUa7BnoXS8KGUEtbURnzGEfKRGidYo4k" />
</application>

</manifest>

package com.example.baidumaptest;

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.widget.Toast;
import com.baidu.mapapi.BMapManager;
import com.baidu.mapapi.SDKInitializer;
import com.baidu.mapapi.map.MapView;
import com.baidu.mapapi.model.inner.GeoPoint;
import java.util.List;

public class MainActivity extends Activity {
private BMapManager mBMapManager;
private MapView mMapView;
private LocationManager mLocationManager;
private String provider;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mBMapManager = new BMapManager();
/**
* 用 SDKInitializer.initialize(getApplicationContext());
* 这个方法初始化，key 也不是写在代码里，而是放到manifast里。
*/
SDKInitializer.initialize(getApplicationContext());
mBMapManager.getContext();
setContentView(R.layout.activity_main);
mMapView = (MapView) findViewById(R.id.map_view);
mMapView.showZoomControls(true);
mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
List<String> providerList = mLocationManager.getProviders(true);
if (providerList.contains(LocationManager.GPS_PROVIDER)) {
provider = LocationManager.GPS_PROVIDER;
} else if (providerList.contains(LocationManager.NETWORK_PROVIDER)) {
provider = LocationManager.NETWORK_PROVIDER;
} else {
Toast.makeText(MainActivity.this, "没有可以定位的位置提供器可用", Toast.LENGTH_SHORT).show();
return;
}
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
//    ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
//   public void onRequestPermissionsResult(int requestCode, String[] permissions,
//                                          int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
Location location = mLocationManager.getLastKnownLocation(provider);
if (location != null) {
navigateTo(location);
}
}
private void navigateTo(Location location){
//MapController controller = mMapView.getController();
//controller.setZoom(16);
GeoPoint point=new GeoPoint((int)(location.getLatitude()*1E6),(int)(location.getLongitude()*1E6));
//mMapView.setCenter(point);
}

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

super.onResume();
}
@Override
protected void onPause(){
mMapView.onPause();

super.onResume();
}
@Override
protected void onDestroy(){
mMapView.onDestroy();

super.onDestroy();
}
}