android - GLSurfaceView 没有出现在 MapView 上

Question

我的目标是将 OpenGL ES 2.0 与 Google map 结合使用。我想创建一个跟随用户从 A 点到 B 点的应用程序。我意识到这可以使用 Google Maps addPolyline 画一条线来完成，但我想改用 OpenGL 以显示重叠的路径。我目前收到一个错误，这是由于错误地设置了 GLSurfaceView。

我在 GoogleMapsTracker 类中的代码如下:

private MapView mapView;
private GoogleMap map;
private GLSurfaceView mGLSurfaceView;

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 */
public static GoogleMapsTracker newInstance() {
    GoogleMapsTracker fragment = new GoogleMapsTracker();
    fragment.setRetainInstance(true);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mapView = (MapView) getActivity().findViewById(R.id.map);
    mGLSurfaceView = new GLSurfaceView(getActivity());

    // Check if the system supports OpenGL ES 2.0
    final ActivityManager am = (ActivityManager) getActivity().getSystemService(Context.ACTIVITY_SERVICE);
    final ConfigurationInfo cInfo = am.getDeviceConfigurationInfo();
    final boolean supportsEs2 = cInfo.reqGlEsVersion >= 0x20000;

    if(supportsEs2){
        // Request an OpenGL ES 2.0 compatible context
        mGLSurfaceView.setEGLContextClientVersion(2);

        // Set the renderer to out demo renderer, defined below
        mGLSurfaceView.setRenderer(new GoogleMapsRenderer(getActivity()));
    } else {
        // This is where you could create an OpenGL ES1.x compatible
        // renderer if you wanted to support both ES 1 and ES 2
        Log.d("Does Not Support ES 2.0", "Does NOT Support ES 2.0");
    }
}

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

    if(SettingsActivity.mUnits){
        v = inflater.inflate(R.layout.google_maps_tracker_metric, container, false);
    } else {
        v = inflater.inflate(R.layout.google_maps_tracker, container, false);
    }

    // Gets the MapView from the XML layout and creates it
    mapView = (MapView) v.findViewById(R.id.map);
    mapView.onCreate(savedInstanceState);

    // Gets to GoogleMap from the MapView and does initialization stuff
    map = mapView.getMap();

    map.getUiSettings().setMyLocationButtonEnabled(true);
    map.getUiSettings().setZoomControlsEnabled(true);
    map.getUiSettings().setRotateGesturesEnabled(true);

    map.setMyLocationEnabled(true);

    map.setMapType(GoogleMap.MAP_TYPE_SATELLITE);

    // Needs to call MapsInitializer before doing any CameraUpdateFactory calls
    MapsInitializer.initialize(this.getActivity());

    // Updates the location and zoom of the MapView
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(45.669656, -111.067373), 18);
    map.animateCamera(cameraUpdate);

    mGLSurfaceView = (GLSurfaceView) v.findViewById(R.id.gl);
    mGLSurfaceView.setEGLContextClientVersion(2);
    GoogleMapsRenderer renderer = new GoogleMapsRenderer(getActivity());
    mGLSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
    mGLSurfaceView.setRenderer(renderer);
    mGLSurfaceView.getHolder().setFormat(PixelFormat.TRANSLUCENT);
    mGLSurfaceView.setRenderMode(GLSurfaceView.RENDERMODE_CONTINUOUSLY);

    mGLSurfaceView.setZOrderOnTop(true);

    return v;
}

我的 XML 代码:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >

<!--fragment
    android:name="com.google.android.gms.maps.MapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/map"
    tools:context=".MainActivity" /-->

<com.google.android.gms.maps.MapView android:id="@+id/map"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"/>

<android.opengl.GLSurfaceView
    android:id="@+id/gl"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.example.tracker.GoogleMapsRenderer"/>

</RelativeLayout>

我收到的错误如下:

    05-22 11:02:34.854  22996-22996/com.example.tracker E/AndroidRuntime﹕ FATAL     EXCEPTION: main
    Process: com.example.tracker, PID: 22996
    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.opengl.GLSurfaceView$GLThread.surfaceCreated()' on a null object reference
            at android.opengl.GLSurfaceView.surfaceCreated(GLSurfaceView.java:523)
            at android.view.SurfaceView.updateWindow(SurfaceView.java:580)
            at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:176)
            at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:944)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1970)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
            at android.view.Choreographer.doCallbacks(Choreographer.java:580)
            at android.view.Choreographer.doFrame(Choreographer.java:550)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5254)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

我很确定我没有正确地把我的观点加在一起。如果有人能指出我的错误以及实现这个想法的更好方法，我们将不胜感激。

Answer 1

我找到了解决问题的方法。只是不确定是否有更好的方法。

基本上，我所做的就是将两个 View (MapView 和 GLSurfaceView)拆分为两个不同的 fragment 。然后使用一个 Activity 类来调用这两个 fragment 。 XML 文件的 fragment 覆盖了相同的区域。下面是我更新的代码。

GoogleMapsActivity:

public class GoogleMapsActivity extends FragmentActivity {

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu items for use in the action bar
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu_main, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    final Context context = this;

    return super.onOptionsItemSelected(item);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setTheme(R.style.DarkTheme);

    if(SettingsActivity.mUnits){
        setContentView(R.layout.google_maps_tracker_metric);
    } else {
        setContentView(R.layout.google_maps_tracker);
    }
}

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

    // Get both fragments shown on the same screen
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

    GoogleMapsTracker fragment;
    fragment = GoogleMapsTracker.newInstance();

    GoogleMapsOGLES fragmentOGL;
    fragmentOGL = GoogleMapsOGLES.newInstance();

    fragmentTransaction.add(R.id.map, fragment);
    fragmentTransaction.add(R.id.gl, fragmentOGL);
    fragmentTransaction.commit();
}

@Override
protected void onPause(){
    super.onPause();
}

@Override
protected void onDestroy() { 
    super.onDestroy(); 
}

GoogleMapsTracker:

public class GoogleMapsTracker extends Fragment implements OnMapReadyCallback {

@Override
public void onMapReady(GoogleMap map){

}

MapView mapView;
GoogleMap map;

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 */
public static GoogleMapsTracker newInstance() {
    GoogleMapsTracker fragment = new GoogleMapsTracker();
    fragment.setRetainInstance(true);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mapView = (MapView) getActivity().findViewById(R.id.maps);
}

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

    v = inflater.inflate(R.layout.fragment_google_maps, container, false);

    // Gets the MapView from the XML layout and creates it
    mapView = (MapView) v.findViewById(R.id.maps);
    mapView.onCreate(savedInstanceState);

    // Gets to GoogleMap from the MapView and does initialization stuff
    map = mapView.getMap();

    map.getUiSettings().setMyLocationButtonEnabled(true);
    map.getUiSettings().setZoomControlsEnabled(true);
    map.getUiSettings().setRotateGesturesEnabled(true);

    map.setMyLocationEnabled(true);

    map.setMapType(GoogleMap.MAP_TYPE_SATELLITE);

    // Needs to call MapsInitializer before doing any CameraUpdateFactory calls
    MapsInitializer.initialize(this.getActivity());

    // Updates the location and zoom of the MapView
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(49.025656, -125.035473), 18);
    map.animateCamera(cameraUpdate);

    return v;
}

GoogleMapsOGLES:

public class GoogleMapsOGLES extends Fragment {
GLSurfaceView mGLSurfaceView;

private boolean rendererSet = false;

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 */
public static GoogleMapsOGLES newInstance() {
    GoogleMapsOGLES fragment = new GoogleMapsOGLES();
    fragment.setRetainInstance(true);
    return fragment;
}

public GoogleMapsOGLES() {
    // Do nothing
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mGLSurfaceView = new GLSurfaceView(getActivity());

    // Check if the system supports OpenGL ES 2.0
    final ActivityManager am = (ActivityManager) getActivity().getSystemService(Context.ACTIVITY_SERVICE);
    final ConfigurationInfo cInfo = am.getDeviceConfigurationInfo();
    final boolean supportsEs2 = cInfo.reqGlEsVersion >= 0x20000;

    if(supportsEs2){
        // Request an OpenGL ES 2.0 compatible context
        mGLSurfaceView.setEGLContextClientVersion(2);

        // Set the renderer to our demo renderer, defined below
        mGLSurfaceView.setRenderer(new GoogleMapsRenderer(getActivity()));
        rendererSet = true;
    } else {
        // This is where you could create an OpenGL ES1.x compatible
        // renderer if you wanted to support both ES 1 and ES 2
        Log.d("Does Not Support ES 2.0", "Does NOT Support ES 2.0");
    }
}

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

    v = inflater.inflate(R.layout.fragment_maps_ogl, container, false);

    mGLSurfaceView = (GLSurfaceView) v.findViewById(R.id.ogl);
    mGLSurfaceView.setEGLContextClientVersion(2);
    GoogleMapsRenderer renderer = new GoogleMapsRenderer(getActivity());

    mGLSurfaceView.setZOrderOnTop(true);
    mGLSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
    mGLSurfaceView.getHolder().setFormat(PixelFormat.TRANSLUCENT);
    mGLSurfaceView.setRenderer(renderer);
    rendererSet = true;
    mGLSurfaceView.setRenderMode(GLSurfaceView.RENDERMODE_CONTINUOUSLY);

    return v;
}

google_maps_tracker.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >

<fragment
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:name="com.example.tracker.GoogleMapsTracker"
    class="com.example.tracker.GoogleMapsTracker"/>

<fragment
    android:id="@+id/gl"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:name="com.example.tracker.GoogleMapsOGLES"
    class="com.example.tracker.GoogleMapsOGLES"/>

</RelativeLayout>

xml 文件中的 fragment 有自己的 xml 文件，这些文件刚刚初始化了 MapView 和 GLSurfaceView。