Question

嗨，我是新来的，希望能找到帮助...... 我发现了一条消息“警告第一个参数发现类型MapActivity需要android.support.v4.app.Fragment”我想将MapActivity作为片段，因为我想在View Pager中添加Map。我正在使用View Pager和View Pager Adapter并在View Pager Adapter中使用两个Array List for Fragments和TabTitles

以下是ViewPagerAdapter的代码

public class ViewPagerAdapter extends FragmentPagerAdapter {

ArrayList<Fragment> fragments = new ArrayList<>();
ArrayList<String> tabTitles = new ArrayList<>();

public void addFragments(Fragment fragments, String titles)
{
    this.fragments.add(fragments);
    this.tabTitles.add(titles);
}

public ViewPagerAdapter(FragmentManager fm)
{
    super(fm);
}

@Override
public Fragment getItem(int position) {
    return fragments.get(position);
}

@Override
public int getCount() {
    return tabTitles.size();
}


@Override
public CharSequence getPageTitle(int position) {
    return tabTitles.get(position);
}
}

这是MainActivity.java的代码

public class MainActivity extends AppCompatActivity {

Toolbar toolbar;
TabLayout tabLayout;
ViewPager viewPager;
ViewPagerAdapter viewPagerAdapter;
/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
private GoogleApiClient client;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    toolbar = (Toolbar) findViewById(R.id.toolBar);
    setSupportActionBar(toolbar);
    tabLayout = (TabLayout) findViewById(R.id.tabLayout);
    viewPager = (ViewPager) findViewById(R.id.viewPager);
    viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
    viewPagerAdapter.addFragments(new HomeFragment(), "Home");
    viewPagerAdapter.addFragments(new SearchFragment(), "Search");
    //   viewPagerAdapter.addFragments(new MapFragment(),"Map");
    viewPagerAdapter.addFragments(new MapsActivity(), "Map");
    viewPager.setAdapter(viewPagerAdapter);
    tabLayout.setupWithViewPager(viewPager);

    client = new         GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}

/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
public Action getIndexApiAction() {
    Thing object = new Thing.Builder()
     .setName("Main Page") // TODO: Define a title for the content shown.
            // TODO: Make sure this auto-generated URL is correct.
            .setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
            .build();
    return new Action.Builder(Action.TYPE_VIEW)
            .setObject(object)
            .setActionStatus(Action.STATUS_TYPE_COMPLETED)
            .build();
}

@Override
public void onStart() {
    super.onStart();


    client.connect();
    AppIndex.AppIndexApi.start(client, getIndexApiAction());
}

@Override
public void onStop() {
    super.onStop();


    AppIndex.AppIndexApi.end(client, getIndexApiAction());
    client.disconnect();
}
}

在activity_main.xml

中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"

tools:context="com.example.lilla.tabdemo.MainActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    >

    <include

        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        layout="@layout/toolbar_layout"

        />
    <android.support.design.widget.TabLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tabLayout"
        app:tabMode="fixed"
        app:tabGravity="fill"
        >

    </android.support.design.widget.TabLayout>

</android.support.design.widget.AppBarLayout>

<android.support.v4.view.ViewPager
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/viewPager"
    >

</android.support.v4.view.ViewPager>

</RelativeLayout>

请帮帮我谢谢....

MapsActivity.java

package com.example.lilla.tabdemo;

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);
SupportMapFragment mapFragment = (SupportMapFragment) 
getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
}


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

    // Add a marker in Sydney and move the camera
    LatLng sydney = new LatLng(-34, 151);
    mMap.addMarker(new MarkerOptions().position(sydney).title("Marker"));
    mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}

Answer 1

您的MapsActivity类必须扩展Fragment类，并且必须从中导入Fragment类 android.support.v4.app.Fragment包。

试试这堂课：

public class MapsActivity extends Fragment implements 
OnMapReadyCallback {

private GoogleMap mMap;
private MapView mMapView;

 @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.activity_maps, container, false);
        getActivity().setTitle("Map");
        mMapView = (MapView) v.findViewById(R.id.map);
        mMapView.onCreate(savedInstanceState);
        mMapView.getMapAsync(this); //this is important
        return v;
    }
  @Override
    public void onResume() {
        super.onResume();
        mMapView.onResume();
    }

    @Override
    public void onPause() {
        super.onPause();
        mMapView.onPause();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mMapView.onDestroy();
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mMapView.onSaveInstanceState(outState);
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        mMapView.onLowMemory();
    }

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

    // Add a marker in Sydney and move the camera
    LatLng sydney = new LatLng(-34, 151);
    mMap.addMarker(new MarkerOptions().position(sydney).title("Marker"));
    mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}

警告第一个参数发现类型MapActivity需要android.support.v4.app.Fragment

1 个答案: