Google Maps在Android Studio中无法清晰显示
- 我在Android Studio中的应用未明确加载位置（地图），它查看了世界的一部分，但仅显示蓝色。
- 我无法查看在布局设计视图中拖动的文本视图和按钮。
应用（分级）
apply plugin: 'com.android.application'
android {
compileSdkVersion 28
defaultConfig {
applicationId "com.example.stylers.maps"
minSdkVersion 18
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:28.0.0-alpha3'
implementation 'com.google.android.gms:play-services-maps:15.0.1'
implementation 'com.google.android.gms:play-services-location:15.0.1'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}
Dataparser（在Java文件夹下）
package com.example.stylers.maps;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class DataParser {
private HashMap<String, String> getPlace(JSONObject googlePlaceJson){
HashMap<String, String> googlePlaceMap = new HashMap<>();
String placeName = "-NA-";
String vicinity = "-NA-";
String latitude = "";
String longitude = "";
String reference = "";
try {
if (!googlePlaceJson.isNull("name")){
placeName = googlePlaceJson.getString("name");
}
if(!googlePlaceJson.isNull("vicinity")){
vicinity = googlePlaceJson.getString("vicinity");
}
latitude = googlePlaceJson.getJSONObject("geometry").getJSONObject("location").getString("lat");
longitude = googlePlaceJson.getJSONObject("geometry").getJSONObject("location").getString("lng");
reference = googlePlaceJson.getString("reference");
googlePlaceMap.put("place name",placeName);
googlePlaceMap.put("vicinity",vicinity);
googlePlaceMap.put("lat",latitude);
googlePlaceMap.put("lng",longitude);
googlePlaceMap.put("reference",reference);
} catch (JSONException e) {
e.printStackTrace();
}
return googlePlaceMap;
}
private List<HashMap<String,String>> getPlaces(JSONArray jsonArray){
int count = jsonArray.length();
List<HashMap<String,String>> placesList = new ArrayList<>();
HashMap<String, String> placeMap = null;
for(int i= 0; i<count; i++){
try {
placeMap = getPlace((JSONObject) jsonArray.get(i));
placesList.add(placeMap);
} catch (JSONException e) {
e.printStackTrace();
}
}
return placesList;
}
public List<HashMap<String,String>> parse(String jsonData){
JSONArray jsonArray = null;
JSONObject jsonObject;
try {
jsonObject = new JSONObject(jsonData);
jsonArray = jsonObject.getJSONArray("results");
} catch (JSONException e) {
e.printStackTrace();
}
return getPlaces(jsonArray);
}
}
DownloadUrl（在Java文件夹下）
package com.example.stylers.maps;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
public class DownloadUrl {
public String readUrl(String myUrl) throws IOException{
String data = "";
InputStream inputStream = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(myUrl);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.connect();
inputStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
StringBuffer sb = new StringBuffer();
String line = "";
while((line = br.readLine())!= null){
sb.append(line);
}
data= sb.toString();
br.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally {
inputStream.close();
urlConnection.disconnect();
}
return data;
}
}
GetNearbyPlaces（在Java文件夹下）
package com.example.stylers.maps;
import android.os.AsyncTask;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.BitmapDescriptor;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
public class GetNearbyPlacesData extends AsyncTask<Object, String, String> {
String googlePlacesData;
GoogleMap mMap;
String url;
@Override
protected String doInBackground(Object... objects) {
mMap = (GoogleMap)objects[0];
url = (String)objects[1];
DownloadUrl downloadUrl = new DownloadUrl();
try {
googlePlacesData = downloadUrl.readUrl(url);
} catch (IOException e) {
e.printStackTrace();
}
return googlePlacesData;
}
@Override
protected void onPostExecute(String s) {
List<HashMap<String, String>> nearbyPlaceList = null;
DataParser parser = new DataParser();
nearbyPlaceList = parser.parse(s);
showNearbyPlaces(nearbyPlaceList);
}
private void showNearbyPlaces(List<HashMap<String, String>> nearbyPlaceList){
for(int i =0; i<nearbyPlaceList.size(); i++){
MarkerOptions markerOptions = new MarkerOptions();
HashMap<String, String> googlePlace = nearbyPlaceList.get(i);
String placeName = googlePlace.get("place_name");
String vicinity = googlePlace.get("vicinity");
double lat= Double.parseDouble(googlePlace.get("lat"));
double lng = Double.parseDouble(googlePlace.get("lng"));
LatLng latLng = new LatLng(lat,lng);
markerOptions.position(latLng);
markerOptions.title(placeName+" : "+vicinity);
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE));
mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(10));
}
}
}
清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.stylers.maps">
<!--
The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
Google Maps Android API v2, but you must specify either coarse or fine
location permissions for the 'MyLocation' functionality.
-->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<!--
The API key for Google Maps-based APIs is defined as a string resource.
(See the file "res/values/google_maps_api.xml").
Note that the API key is linked to the encryption key used to sign the APK.
You need a different API key for each encryption key, including the release key that is used to
sign the APK for publishing.
You can define the keys for the debug and release targets in src/debug/ and src/release/.
-->
<meta-data
android:name="com.google.android.geo.API_KEY"
android:value="@string/google_maps_key" />
<activity
android:name=".MapsActivity"
android:label="@string/title_activity_maps">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MapsActivity.java（在Java文件夹下）
package com.example.stylers.maps;
import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import java.io.IOException;
import java.util.List;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
private GoogleApiClient client;
private LocationRequest locationRequest;
private Location lastLocation;
private Marker currentLocationMarker;
public static final int REQUEST_LOCATION_CODE = 99;
int PROXIMITY_RADIUS=10000;
double latitude,longitude;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.M){
checkLocationPermission();
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch(requestCode)
{
case REQUEST_LOCATION_CODE:
if(grantResults.length > 0 && grantResults[0]==PackageManager.PERMISSION_GRANTED)
{
//permission is granted
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)==PackageManager.PERMISSION_GRANTED){
if(client == null){
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
}
else{
Toast.makeText(this,"Permission Denied",Toast.LENGTH_LONG).show();
}
return;
}
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION)== PackageManager.PERMISSION_GRANTED){
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
protected synchronized void buildGoogleApiClient(){
client = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
client.connect();
}
@Override
public void onLocationChanged(Location location) {
lastLocation = location;
if(currentLocationMarker != null){
currentLocationMarker.remove();
}
LatLng latLng = new LatLng(location.getLatitude(),location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Location");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE));
currentLocationMarker = mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomBy(10));
if(client != null)
{
LocationServices.FusedLocationApi.removeLocationUpdates(client, this);
}
}
public void onClick(View v) {
switch (v.getId()){
case R.id.B_search: {
EditText tf_location = (EditText) findViewById(R.id.TF_location);
String location = tf_location.getText().toString();
List<Address> addressList = null;
MarkerOptions mo = new MarkerOptions();
if (!location.equals("")) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 5);
} catch (IOException e) {
e.printStackTrace();
}
for (int i = 0; i < addressList.size(); i++) {
Address myAddress = addressList.get(i);
LatLng latlng = new LatLng(myAddress.getLatitude(), myAddress.getLongitude());
mo.position(latlng);
mo.title("Your search result");
mMap.addMarker(mo);
mMap.animateCamera(CameraUpdateFactory.newLatLng(latlng));
}
}
}
break;
case R.id.B_pharmacy:
mMap.clear();
String pharmacy = "pharmacy";
String url = getUrl(latitude,longitude,pharmacy);
Object dataTransfer[] = new Object[2];
dataTransfer[0]= mMap;
dataTransfer[1]=url;
GetNearbyPlacesData getNearbyPlacesData = new GetNearbyPlacesData();
getNearbyPlacesData.execute(dataTransfer);
Toast.makeText(MapsActivity.this,"Showing nearby pharmacy", Toast.LENGTH_LONG).show();
break;
}
}
private String getUrl(double latitude, double longitude, String nearbyPlace){
StringBuilder googlePlaceUrl = new StringBuilder("https://maps.googleapis.com/maps/api/place/findplacefromtext/");
googlePlaceUrl.append("location"+latitude+","+longitude);
googlePlaceUrl.append("&radius="+PROXIMITY_RADIUS);
googlePlaceUrl.append("&type="+nearbyPlace);
googlePlaceUrl.append("&sensor=true");
googlePlaceUrl.append("&key="+"AIzaSyA9cANY3r4v26Sz9dPbLlvuv_1WP19vI7w");
return googlePlaceUrl.toString();
}
@Override
public void onConnected(@Nullable Bundle bundle) {
locationRequest = new LocationRequest();
locationRequest.setInterval(1000);
locationRequest.setFastestInterval(1000);
locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION)==PackageManager.PERMISSION_GRANTED){
LocationServices.FusedLocationApi.requestLocationUpdates(client,locationRequest,this);
}
}
public boolean checkLocationPermission(){
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)!= PackageManager.PERMISSION_GRANTED){
if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)){
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},REQUEST_LOCATION_CODE);
}
else
{
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},REQUEST_LOCATION_CODE);
}
return false;
}
else
return true;
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
}
Activity_maps.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="visible">
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="470dp"
tools:context=".MapsActivity" />
<EditText
android:id="@+id/TF_location"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:ems="10"
android:inputType="textPersonName"
android:visibility="visible" />
<Button
android:id="@+id/B_search"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:onClick="onClick"
android:text="Search"
android:visibility="visible" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="visible">
<Button
android:id="@+id/B_pharmacy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Pharmacy"
android:visibility="visible" />
</LinearLayout>
</RelativeLayout>
1 个答案:
答案 0 :(得分：0)
在OnMapReady中，您可以将地图居中放置在用户的中心，而不仅仅是在onLocationChanged（）上，这样可以防止您在位置不变的情况下看到蓝屏
您能否在onMapReady上尝试以下操作
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
// Set the map's camera position to the current location of the device.
if (mLastLocation != null) {
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(mLastLocation.getLatitude(),mLastLocation.getLongitude()), DEFAULT_ZOOM));
}
}
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