java - fragment 上的MapFragment

我正在开发一个在片段上显示地图的应用程序。一切都准备好了，但是有一点小事情让我无法完成。

gMapFragment.java：

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;


public class gMapFragment extends Fragment implements OnMapReadyCallback {


    public gMapFragment() {
        // Required empty public constructor
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_map, container, false);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        MapFragment fragment = (MapFragment) getChildFragmentManager().findFragmentById(R.id.map);
        fragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {

        LatLng marker = new LatLng(46.33328, 15.38173);
        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(marker,13));
        googleMap.addMarker(new MarkerOptions().title(("HERE WE ARE!")).position(marker));

    }
}

我从另一个frament中的button调用此片段，这是调用它的方法：

public void onClick(View view) {
    Fragment fragment = null;
    switch (view.getId()) {
        case R.id.SearchButton:
            fragment = new gMapFragment();
            replaceFragment(fragment);
            break;
    }
}

public void replaceFragment(Fragment someFragment) {
    FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.replace(R.id.fragment_container, someFragment);
    transaction.addToBackStack(null);
    transaction.commit();
}

我收到错误消息“ gMapFragment无法转换为片段”。如何解决此问题？谢谢！

最佳答案

首先，请确保您与Fragment导入一致。在所有类中使用import android.app.Fragment或在所有类中使用import android.support.v4.app.Fragment;。不要混搭。

然后，将其添加到“活动”中：

public void openMapFragment() {
    Fragment fragment = new gMapFragment();
    replaceFragment(fragment);
}

//moved to Activity from the Fragment
public void replaceFragment(Fragment someFragment) {
    FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.replace(R.id.fragment_container, someFragment);
    transaction.addToBackStack(null);
    transaction.commit();
}

然后，在Fragment onClick()方法中，只需调用Activity来执行FragmentTransaction：

public void onClick(View view) {
    switch (view.getId()) {
        case R.id.SearchButton:
            MainActivity activity = (MainActivity) getActivity();
            if (activity != null) {
                activity.openMapFragment();
            }
            break;
    }
}