java - 不可转换的类型无法转换

Question

我正在尝试实现映射，但遇到不可转换类型的错误；无法将 android.support.v4.app.Fragment 转换为 com.google.android.gms.maps.SupportMapFragment

我看过一些资源，但对我没有用

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

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.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends FragmentActivity implements         OnMapReadyCallback {

private GoogleMap mMap;

@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);
}

Inconvertible types; cannot cast 'android.support.v4.app.Fragment' to 'com.google.android.gms.maps.SupportMapFragment'

Answer 1

根据 Google Play services Android release notes for play-services-maps:17.0.0 :

Warning: This release is a MAJOR version update and breaking change.

• Update your app to use Jetpack (AndroidX); follow the instructions in Migrating to AndroidX.

map 17.0.0 已切换到 AndroidX .这意味着 SupportMapFragment 现在扩展了 androidx.fragment.app.Fragment ，而不是等效的支持库。您需要切换回 16.1.0 或将您的应用迁移到 AndroidX。