java.lang.RuntimeException：无法启动活动 java.lang.NullPointerException 02-21 22:55:01.480：E/And

Question

我想制作地图并在谷歌地图中显示所有标记或位置。我已经为纬度和经度创建了一个类数据库。我在谷歌地图中调用纬度和经度来查看位置。我有这个代码

public void onLocationChanged(Location location) {
        Intent intent = new Intent(getApplicationContext(),Database_Puskesmas.class);

        msg_latitude = intent.getStringExtra("dataLatitude");
        msg_longitude = intent.getStringExtra("dataLogitude");

        double la = Double.parseDouble(msg_latitude);
        double lo = Double.parseDouble(msg_longitude);

        //Database_Puskesmas db = new Database_Puskesmas(this);

         LatLng latLng = new LatLng(la, lo);

        Marker marker = googleMap.addMarker(new MarkerOptions()
        .position(latLng).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));

        googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

    }

但是当我运行程序时，我得到以下错误：

02-21 22:55:01.480: E/AndroidRuntime(4072): FATAL EXCEPTION: main
02-21 22:55:01.480: E/AndroidRuntime(4072): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.application.bpjs/com.application.bpjs.PetaPuskesmas_Activity}: java.lang.NullPointerException
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.ActivityThread.access$700(ActivityThread.java:134)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.os.Looper.loop(Looper.java:137)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.ActivityThread.main(ActivityThread.java:4867)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at java.lang.reflect.Method.invokeNative(Native Method)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at java.lang.reflect.Method.invoke(Method.java:511)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at dalvik.system.NativeStart.main(Native Method)
02-21 22:55:01.480: E/AndroidRuntime(4072): Caused by: java.lang.NullPointerException
02-21 22:55:01.480: E/AndroidRuntime(4072):     at java.lang.StringToReal.parseDouble(StringToReal.java:244)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at java.lang.Double.parseDouble(Double.java:295)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at com.application.bpjs.PetaPuskesmas_Activity.onLocationChanged(PetaPuskesmas_Activity.java:491)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at com.application.bpjs.PetaPuskesmas_Activity.onCreate(PetaPuskesmas_Activity.java:151)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.Activity.performCreate(Activity.java:5047)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
02-21 22:55:01.480: E/AndroidRuntime(4072):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056)
02-21 22:55:01.480: E/AndroidRuntime(4072):     ... 11 more
02-21 22:55:10.409: I/Process(4072): Sending signal. PID: 4072 SIG: 9

Answer 1

这里：

    Intent intent = new Intent(getApplicationContext(),Database_Puskesmas.class);
    msg_latitude = intent.getStringExtra("dataLatitude");
    msg_longitude = intent.getStringExtra("dataLogitude");

只准备意图而不添加 dataLatitude 和 dataLogitude 键并绑定从 Intent 获取两个键。

使用onLocationChanged方法location参数获取Latitude和Logitudelike：

double la = location.getLatitude();
double lo = location.getLongitude();