How to use Android FragmentPagerAdapter with MapView

Question

I'm pretty new to Android programming so pardon my noobness.

I tried using some sample code from the Android tutorial site. I'm trying to get a mapview into a FragmentPagerAdapter. I managed to get both separate sample codes running on their own but can't figure out how to put it together.

First portion here:

MainActivity.java

package com.jhdev.places;

import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MainActivity extends FragmentActivity implements ActionBar.TabListener {

/**
 * The {@link android.support.v4.view.PagerAdapter} that will provide fragments for each of the
 * three primary sections of the app. We use a {@link android.support.v4.app.FragmentPagerAdapter}
 * derivative, which will keep every loaded fragment in memory. If this becomes too memory
 * intensive, it may be best to switch to a {@link android.support.v4.app.FragmentStatePagerAdapter}.
 */
AppSectionsPagerAdapter mAppSectionsPagerAdapter;

/**
 * The {@link ViewPager} that will display the three primary sections of the app, one at a
 * time.
 */
ViewPager mViewPager;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Create the adapter that will return a fragment for each of the three primary sections
    // of the app.
    mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());

    // Set up the action bar.
    final ActionBar actionBar = getActionBar();

    // Specify that the Home/Up button should not be enabled, since there is no hierarchical
    // parent.
    actionBar.setHomeButtonEnabled(false);

    // Specify that we will be displaying tabs in the action bar.
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Set up the ViewPager, attaching the adapter and setting up a listener for when the
    // user swipes between sections.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mAppSectionsPagerAdapter);
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
        @Override
        public void onPageSelected(int position) {
            // When swiping between different app sections, select the corresponding tab.
            // We can also use ActionBar.Tab#select() to do this if we have a reference to the
            // Tab.
            actionBar.setSelectedNavigationItem(position);
        }
    });

    // For each of the sections in the app, add a tab to the action bar.
    for (int i = 0; i < mAppSectionsPagerAdapter.getCount(); i++) {
        // Create a tab with text corresponding to the page title defined by the adapter.
        // Also specify this Activity object, which implements the TabListener interface, as the
        // listener for when this tab is selected.
        actionBar.addTab(
                actionBar.newTab()
                        .setText(mAppSectionsPagerAdapter.getPageTitle(i))
                        .setTabListener(this));
    }
}

@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}

@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
    // When the given tab is selected, switch to the corresponding page in the ViewPager.
    mViewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to one of the primary
 * sections of the app.
 */
public static class AppSectionsPagerAdapter extends FragmentPagerAdapter {

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

    @Override
    public Fragment getItem(int i) {
        switch (i) {
            case 0:
                // The first section of the app is the most interesting -- it offers
                // a launchpad into the other demonstrations in this example application.
                return new LaunchpadSectionFragment();

            case 1:
                return new BasicMapFragment();

            default:
                // The other sections of the app are dummy placeholders.
                Fragment fragment = new DummySectionFragment();
                Bundle args = new Bundle();
                args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, i + 1);
                fragment.setArguments(args);
                return fragment;
        }
    }

    @Override
    public int getCount() {
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return "Section " + (position + 1);
    }
}

/**
 * A fragment that launches other parts of the demo application.
 */
public static class LaunchpadSectionFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_section_launchpad, container, false);

        // Demonstration of a collection-browsing activity.
        rootView.findViewById(R.id.demo_collection_button)
                .setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        Intent intent = new Intent(getActivity(), CollectionDemoActivity.class);
                        startActivity(intent);
                    }
                });

        // Demonstration of navigating to external activities.
        rootView.findViewById(R.id.demo_external_activity)
                .setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        // Create an intent that asks the user to pick a photo, but using
                        // FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET, ensures that relaunching
                        // the application from the device home screen does not return
                        // to the external activity.
                        Intent externalActivityIntent = new Intent(Intent.ACTION_PICK);
                        externalActivityIntent.setType("image/*");
                        externalActivityIntent.addFlags(
                                Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                        startActivity(externalActivityIntent);
                    }
                });

        return rootView;
    }
}

public static class BasicMapFragment extends Fragment {
    // Load the fragment for Basic Map. links to BasicMapActivity
    public static final String ARG_SECTION_NUMBER = "section_number";

    public BasicMapFragment() {

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    //Todo I don't know what to add in this area in order to start the BasicMapActivity in this fragment window

        return rootView;
    }

}

This is the mapview activity that I want to run inside my second window:

BasicMapActivity.java

package com.jhdev.places;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;

/**
 * This shows how to create a simple activity with a map and a marker on the map.
 * <p>
 * Notice how we deal with the possibility that the Google Play services APK is not
 * installed/enabled/updated on a user's device.
 */
public class BasicMapActivity extends FragmentActivity {
    /**
     * Note that this may be null if the Google Play services APK is not available.
     */
    private GoogleMap mMap;

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

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    /**
     * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
     * installed) and the map has not already been instantiated.. This will ensure that we only ever
     * call {@link #setUpMap()} once when {@link #mMap} is not null.
     * <p>
     * If it isn't installed {@link SupportMapFragment} (and
     * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
     * install/update the Google Play services APK on their device.
     * <p>
     * A user can return to this FragmentActivity after following the prompt and correctly
     * installing/updating/enabling the Google Play services. Since the FragmentActivity may not have been
     * completely destroyed during this process (it is likely that it would only be stopped or
     * paused), {@link #onCreate(Bundle)} may not be called again so we should call this method in
     * {@link #onResume()} to guarantee that it will be called.
     */
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    /**
     * This is where we can add markers or lines, add listeners or move the camera. In this case, we
     * just add a marker near Africa.
     * <p>
     * This should only be called once and when we are sure that {@link #mMap} is not null.
     */
    private void setUpMap() {
        mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
    }
}

Your advice is much appreciated. Thanks!

Answer 1

You should use a MapFragment , rather than a subclass of regular Fragment . If you'd like, you can have your BasicMapFragment class extend MapFragment so that you can customize it's behavior.

https://developers.google.com/maps/documentation/android/reference/com/google/android/gms/maps/MapFragment