小编Jer*_*iah的帖子

在经历了与我的头衔相关的SO问题之后,我找不到问题的解决方案.我有一个NullPointerException在mapFragment.getMapAsync.以下是我的MapActivity代码.

package com.example.jerofad.mylocation;
import android.app.FragmentManager;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
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) this.getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        // Add …

请问我对如何产生星级评分有疑问.我的意思是,在用户输入了评级参数的值并且程序计算了总费率之后,程序将如何以星形而不是数字生成结果.如果评级为5,则应生成*****.谢谢.