java - Android MapBlocks 中的空点异常错误

Question

我正在尝试关注This tutorial 我收到一个错误这是堆栈跟踪

Process: com.example.mapp, PID: 7624
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mapp/com.example.mapp.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.mapbox.mapboxsdk.maps.MapView.onCreate(android.os.Bundle)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.mapbox.mapboxsdk.maps.MapView.onCreate(android.os.Bundle)' on a null object reference
        at com.example.mapp.MainActivity.onCreate(MainActivity.java:21)

这是activity_main.xml 的 map View 部分

    <com.mapbox.mapboxsdk.maps.MapView
        android:id="@+id/mapView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        mapbox:mapbox_cameraTargetLat="37.7747"
        mapbox:mapbox_cameraTargetLng="-122.4443"
        mapbox:mapbox_styleUrl="mapbox://styles/mapbox/streets-v10"
        mapbox:mapbox_cameraZoom="12"
        />

这是完整的MainActivity.Java(删除了所有导入+ map 框的更多功能)

public class MainActivity extends AppCompatActivity {

    private MapView mapView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Mapbox.getInstance(this, getString(R.string.access_token) );
        mapView = (MapView) findViewById(R.id.mapView);
        mapView.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
    }

    @Override
    protected void onStart() {
        super.onStart();
        mapView.onStart();
    }

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

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

我尝试了以下链接，但它们不起作用 link 1 link 2 link 4

提前致谢。

Answer 1

您正在关注的 YouTube 视频有点旧了。现在设置一个简单的 MapView 的方式有所不同。例如，您无法再通过 XML 设置 map 样式 URL。

https://docs.mapbox.com/android/maps/examples/create-a-simple-map-view显示设置 Mapbox map 的基本方法。