java - fragment 上的 MapFragment

Question

我正在开发一个在 fragment 上显示 map 的应用程序。一切都已准备就绪，但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));

    }
}

我从另一个框架中的按钮调用这个 fragment ，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“gMapFragment 无法转换为 fragment ”知道如何解决此问题吗？谢谢!

Answer 1

首先，确保您的 Fragment 导入保持一致。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; 。不要混合搭配。

然后，将其添加到 Activity 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，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;
    }
}