mSecurityInputMethodService 在 logcat 中为空

I wrote a little android app that should display the current location (last known location) of the smartphone. Although I copied the example code, and tried several other solutions, It seems to have the same error every time. My app consists of a button. Pressing the button should log the longitude and latitude, but only logs "mSecurityInputMethodService is null".

这是 MainActivity.java:

public class MainActivity extends Activity {
int response;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Button button = (Button)findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            onbutclick();
        }
    });

}
public void onbutclick(){
    LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
    if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){
        Location loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if(loc != null){
            Log.d("Latitude",Double.toString(loc.getLatitude()));
            Log.d("Longitude",Double.toString(loc.getLongitude()));
        }

    }else{
        ActivityCompat.requestPermissions(this,new String[] {Manifest.permission.ACCESS_FINE_LOCATION},response);
        Intent inte = getIntent();
        finish();
        startActivity(inte);
    }
}

我还在 Manifest 文件中使用了 <uses-permission>.我真的很感激解释 "mSecurityInputMethodService is null" 的真正含义.

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