Android 地图碎片上的黑屏

异步任务结束后，我使用startActivity（intent）调用MapActivity。当这样做时，我得到了MainActivity的基本视图，然后当MapFragment sims启动时会出现一个黑屏

我的日志没有错误

我使用android 9在模拟像素5X上运行它

我还没有触及活动的布局。是什么导致了黑屏

MainActivity.java

public class MainActivity extends AppCompatActivity {

String json_string;

JSONObject json_object;

JSONArray json_array;

protected static JSONArray JSON_ARRAY;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Intent myIntent = new Intent(this, getJSON.class);
    startActivityForResult(myIntent, 1);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 1 && resultCode == RESULT_OK){
        json_string = data.getStringExtra("JSON_string");
        Log.v("test 7",json_string);

        JSON_ARRAY = traitement(json_string);
        Intent myIntent2 = new Intent(this, MapsActivity.class);
        startActivity(myIntent2);
    }
}

public JSONArray traitement(String json){
    try {
        json_object = new JSONObject(json);
    } catch (JSONException e) {
        e.printStackTrace();
    }

    try {

        json_array = json_object.getJSONArray("nightfall");
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return json_array;
}

public static JSONArray getJSON_ARRAY() {
    return JSON_ARRAY;
}
}

    private GoogleMap mMap;

JSONArray json_array;

Double lat, lng;

String nom;

LatLng lieu;

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


/**
 * 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) {

    json_array = MainActivity.getJSON_ARRAY();
    mMap = googleMap;

    int count = 0;
    try {
        while(count<json_array.length()) {
            JSONObject JO = json_array.getJSONObject(count);
            lat = JO.getDouble("lat");
            lng = JO.getDouble("lon");
            nom = JO.getString("nom");

            lieu = new LatLng(lat, lng);
            mMap.addMarker(new MarkerOptions().position(lieu).title(nom));
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

MapsActivity.java

public class MainActivity extends AppCompatActivity {

String json_string;

JSONObject json_object;

JSONArray json_array;

protected static JSONArray JSON_ARRAY;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Intent myIntent = new Intent(this, getJSON.class);
    startActivityForResult(myIntent, 1);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 1 && resultCode == RESULT_OK){
        json_string = data.getStringExtra("JSON_string");
        Log.v("test 7",json_string);

        JSON_ARRAY = traitement(json_string);
        Intent myIntent2 = new Intent(this, MapsActivity.class);
        startActivity(myIntent2);
    }
}

public JSONArray traitement(String json){
    try {
        json_object = new JSONObject(json);
    } catch (JSONException e) {
        e.printStackTrace();
    }

    try {

        json_array = json_object.getJSONArray("nightfall");
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return json_array;
}

public static JSONArray getJSON_ARRAY() {
    return JSON_ARRAY;
}
}

    private GoogleMap mMap;

JSONArray json_array;

Double lat, lng;

String nom;

LatLng lieu;

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


/**
 * 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) {

    json_array = MainActivity.getJSON_ARRAY();
    mMap = googleMap;

    int count = 0;
    try {
        while(count<json_array.length()) {
            JSONObject JO = json_array.getJSONObject(count);
            lat = JO.getDouble("lat");
            lng = JO.getDouble("lon");
            nom = JO.getString("nom");

            lieu = new LatLng(lat, lng);
            mMap.addMarker(new MarkerOptions().position(lieu).title(nom));
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

私有谷歌地图mMap；
JSONArray json_数组；
双lat，液化天然气；
字符串名称；
拉特林；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_映射）；
//获取SupportMapFragment，并在地图准备好使用时收到通知。
SupportMapFragment mapFragment=（SupportMapFragment）getSupportFragmentManager（）
.findFragmentById（R.id.map）；
getMapAsync（这个）；
}
/**
*一旦可用，就可以操纵贴图。
*当映射准备好使用时，将触发此回调。
*这是我们可以添加标记或线条、添加侦听器或移动摄影机的地方。在这种情况下,，
*我们只是在澳大利亚悉尼附近加了一个标记。
*如果设备上未安装Google Play服务，系统将提示用户安装
*它位于SupportMapFragment中。此方法仅在用户完成后触发
*已安装Google Play服务并返回应用程序。
*/
@凌驾
4月1日公开作废（谷歌地图谷歌地图）{
json_array=MainActivity.getJSON_array（）；
mMap=谷歌地图；
整数计数=0；
试一试{
虽然（计数通常黑屏是由不正确的API密钥设置引起的。我正在使用通过google API控制台提供的API，google map的API正在运行，并且密钥在google_maps_API.xml和AndroidManifest.xml中正确显示。这个问题只发生在Android 9中吗？它在其他Android版本中正常工作吗？通常黑屏是由不正确的API密钥设置导致我正在使用通过google API控制台提供的API，google map的API正在运行，并且密钥在google_maps_API.xml和AndroidManifest.xml中正确显示。该问题是否仅在Android 9中出现？它是否在其他Android版本中正常工作？？？