Question

我正在研究googlemap carousel（寻呼机）项目，需要在复杂的布局中显示google地图，但每次我移动寻呼机时，都没有加载mapfragment。如果我翻回来，地图会突然出现。这是我的代码：

MainActivity

import android.content.Context;
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.FragmentStatePagerAdapter;
import android.support.v4.view.PagerTabStrip;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.*;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
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 java.util.ArrayList;

public class MainActivity extends FragmentActivity {
    static final LatLng HAMBURG = new LatLng(53.558, 9.927);
    static final LatLng KIEL = new LatLng(53.551, 9.993);
    private GoogleMap map;
    private ArrayList<MarkerOptions> mMarkers;

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


        ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
        viewPager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));


    }


}

class MyMapFragment extends SupportMapFragment {
    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        GoogleMap map = getMap();

        if (savedInstanceState == null) {
            CameraUpdate center =
                    CameraUpdateFactory.newLatLng(new LatLng(40.76793169992044,
                            -73.98180484771729));
            CameraUpdate zoom = CameraUpdateFactory.zoomTo(15);

            map.moveCamera(center);
            map.animateCamera(zoom);
        }

        addMarker(map, 40.748963847316034, -73.96807193756104);
        addMarker(map, 40.76866299974387, -73.98268461227417);
        addMarker(map, 40.765136435316755, -73.97989511489868);
        addMarker(map, 40.70686417491799, -74.01572942733765);
        setRetainInstance(true);
    }

    private void addMarker(GoogleMap map, double lat, double lon) {
        map.addMarker(new MarkerOptions().position(new LatLng(lat, lon)));

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        View view = inflater.inflate(R.layout.ttt, null);
        getActivity().getSupportFragmentManager()
                .beginTransaction()
                .add(R.id.map_layout, newInstance())
                .commit();
        return view;
    }
}

class MyPagerAdapter extends FragmentStatePagerAdapter {

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

    @Override
    public Fragment getItem(int i) {
        return new MyMapFragment();  //To change body of implemented methods use File | Settings | File Templates.
    }

    @Override
    public int getCount() {
        return 10;  //To change body of implemented methods use File | Settings | File Templates.
    }

    @Override
    public String getPageTitle(int position) {
        return ("page " + String.valueOf(position + 1));
    }
}

class MapAwarePager extends ViewPager {
    public MapAwarePager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected boolean canScroll(View v, boolean checkV, int dx, int x,
                                int y) {
        if (v instanceof SurfaceView || v instanceof TextureView || v instanceof PagerTabStrip) {
            return (true);
        }

        return (super.canScroll(v, checkV, dx, x, y));
    }
}

和main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
        >
    <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Hello World, MainActivity"
            />
    <view android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          class="com.spot.maps.MapAwarePager" android:id="@+id/view_pager"/>
</LinearLayout>

和ttt.xml我在哪里放置片段：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <EditText
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:text="New EditText"
            android:id="@+id/editText" android:layout_gravity="left|center_vertical" android:layout_weight="1"/>
    <FrameLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" android:layout_gravity="left|center_vertical" android:layout_weight="1"
            android:id="@+id/map_layout">
    </FrameLayout>
    <Button
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:text="New Button"
            android:id="@+id/button" android:layout_weight="1"/>
</LinearLayout>

我的Mainfest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.spot.maps"
          android:versionCode="1"
          android:versionName="1.0">
    <uses-sdk android:minSdkVersion="10"/>
    <permission
    android:name="com.spot.maps.permission.MAPS_RECEIVE"
    android:protectionLevel="signature" />
    <uses-feature
            android:glEsVersion="0x00020000"
            android:required="true" />
    <uses-permission android:name="com.spot.maps.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <!--<uses-permission android:name="android.permission.INTERNET"/>-->
    <application android:label="@string/app_name" android:icon="@drawable/ic_launcher" android:hardwareAccelerated="true">

        <activity android:name="MainActivity"
                  android:screenOrientation="portrait"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <meta-data
                android:name="com.google.android.maps.v2.API_KEY"
                android:value="AIzaSyChbP6k9pnX4kLoTnOfXHFJK5Y_nM1wSqQ" />
    </application>
</manifest>

我提出THIS VIDEO以便更好地理解。

希望你能帮助我。

Answer 1

Viewpager运行时很难确定，为unexpected results留下了很多空间。

请注意寻呼机的适配器。很多例子都使用内部类来实现。

注2 ViewPagers

中使用的一般类型的适配器

请注意，任一适配器都可以将ArrayList的实例绑定到视图，并且可以使用完全不同的方式来加载ViewPager框架。 INSTEAD迭代你对FragmentTransaction的调用，你可以在调用adapter.notifyDataSetChanged（）之前简单地将片段添加到适配器中的ArrayList对象。 ViewPager应该自动管理内存并管理从更大的ArrayList对象中仅保留内存中最相关的mapView。

查看last idea

的示例

简答：

通过ArrayList对象加载片段适配器，然后像许多样本一样调用“onNotifyDataSetChanged（）”......

FragmentStatePagerAdapter上的SupportMapFragment。我只能看到前一个和第一个地图片段

1 个答案: