【发布时间】：2019-06-23 08:48:29
【问题描述】：
我创建了一个谷歌地图的活动，当错误弹出时，错误是在活动的构建完成后出现的。 错误是：
Inconvertible types; cannot cast 'android.support.v4.app.Fragment' to 'com.google.android.gms.maps.SupportMapFragment'
在行中（在 MapsActivity 中）：
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() .findFragmentById(R.id.map);
而且我也在资源中输入了API密钥！！
进口：
import android.support.v4.app.FragmentActivity;
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;
清单：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.purabjain.memorableplaces">
<!--
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" />
<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"
tools:replace="android:appComponentFactory"
android:appComponentFactory="whateverString">
<!--
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"></activity>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
build.gradle：
android {
compileSdkVersion 28
defaultConfig {
applicationId "com.purabjain.memorableplaces"
minSdkVersion 21
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
implementation 'com.google.android.gms:play-services-maps:17.0.0'
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'
}
地图活动：
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
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);
}
/**
* 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;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));*/
}
}
api.xml：
<!--
TODO: Before you run your application, you need a Google Maps API key.
To get one, follow this link, follow the directions and press "Create" at the end:
https://console.developers.google.com/flows/enableapi?apiid=maps_android_backend&keyType=CLIENT_SIDE_ANDROID&r=E6:56:90:82:E2:58:42:66:59:4C:5A:F2:E5:9B:64:06:EC:1E:05:49%3Bcom.purabjain.memorableplaces
You can also add your credentials to an existing key, using these values:
Package name:
E6:56:90:82:E2:58:42:66:59:4C:5A:F2:E5:9B:64:06:EC:1E:05:49
SHA-1 certificate fingerprint:
E6:56:90:82:E2:58:42:66:59:4C:5A:F2:E5:9B:64:06:EC:1E:05:49
Alternatively, follow the directions here:
https://developers.google.com/maps/documentation/android/start#get-key
Once you have your key (it starts with "AIza"), replace the "google_maps_key"
string in this file.
-->
<string name="google_maps_key" templateMergeStrategy="preserve" translatable="false">AIzaSyDaCq_mx5h741VnM-4tNkNmQiT70yf7ykw</string>
</resources>
【问题讨论】：
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这里为什么有C++标签？
标签： java