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I tried to get an address from a pointed location on google maps and get this error :

Blockquote FATAL EXCEPTION: main Process: elder.msu.testlocationapp, PID: 23559 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{elder.msu.testlocationapp/elder.msu.testlocationapp.MapsActivity}: java.lang.NullPointerException: Attempt to read from field 'double com.google.android.gms.maps.model.LatLng.latitude' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2366) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2515) at android.app.ActivityThread.access$1000(ActivityThread.java:154) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1379) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:157) at android.app.ActivityThread.main(ActivityThread.java:5571) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:745) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:635) Caused by: java.lang.NullPointerException: Attempt to read from field 'double com.google.android.gms.maps.model.LatLng.latitude' on a null object reference at elder.msu.testlocationapp.MapsActivity.(MapsActivity.java:32) at java.lang.Class.newInstance(Native Method) at android.app.Instrumentation.newActivity(Instrumentation.java:1068) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2356) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2515)  at android.app.ActivityThread.access$1000(ActivityThread.java:154)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1379)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:157)  at android.app.ActivityThread.main(ActivityThread.java:5571)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:745)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:635) 

I every necessary thing in my manifest. Here is my code for the map activity

public void onMapReady(GoogleMap googleMap) {
    mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
        @Override
        public void onMapClick(LatLng latLng) {
            markerOptions.position(latLng);
            markerOptions.title(latLng.latitude + " : " + latLng.longitude);
            mMap.clear();
            mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
            mMap.addMarker(markerOptions);
        }
    });

private void getAddress(){

    Geocoder geocoder;
    final List<Address> addresses;
    geocoder = new Geocoder(this, Locale.getDefault());
    try{
        addresses = geocoder.getFromLocation(latitude,longitude,1);

        if (addresses!=null && addresses.size() > 0){
            address = addresses.get(0).getAddressLine(0);
            city = addresses.get(0).getLocality();
        }

    }catch (IOException e){
        e.printStackTrace();
        Toast.makeText(getApplicationContext(), "Cannot get data", Toast.LENGTH_SHORT).show();
    }


    btnOK.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getAddress();
            confirmData(address, city);

        }
    });


}

private void confirmData(String address, String city) {

    Intent intent = new Intent(getApplicationContext(), MainActivity.class);
    Bundle bundle = new Bundle();
    intent.putExtra("data", bundle);
    intent.putExtra("address", address);
    intent.putExtra("city", city);
    startActivity(intent);
    finish();
}
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1 回答 1

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要停止此错误，只需包装地图单击侦听器代码。

if (latLng != null) {
    markerOptions.position(latLng);
    markerOptions.title(latLng.latitude + " : " + latLng.longitude);
    mMap.clear();
    mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
    mMap.addMarker(markerOptions);
}

至于为什么它给出一个空值，我不确定。这是否在活动首次启动时的 onCreate 期间发生？

于 2018-07-11T21:17:13.583 回答