title: How to get a SurfaceHolder with a valid Surface (needed by EGL.eglCreateWindowSurface)?
body: <p>I try to initialize GLES with EGL (because I want to draw from the main thread
  instead of using a Renderer and drawing from inside onDrawFrame). I get the error: "Make sure the SurfaceView or associated SurfaceHolder has a valid Surface". Obviously mEgl.eglCreateWindowSurface fails because surfaceHolder has not a valid surface. How do I get a SurfaceHolder with a valid Surface to proceed?</p>
  
  <p>My Activity.onCreate method is:</p>
  
  <pre><code>protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  
      GLSurfaceView surfaceView = new GLSurfaceView(this);
      setContentView(surfaceView);
      SurfaceHolder surfaceHolder = surfaceView.getHolder();
      Surface surface = surfaceHolder.getSurface();
      Log.v("HelloAndroid", "surface.isValid()= " + Boolean.toString(surface.isValid()));
  
      EGL10 mEgl = (EGL10) EGLContext.getEGL();
      EGLDisplay mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
      int[] version = new int[2];
      mEgl.eglInitialize(mEglDisplay, version);
      EGLConfig[] configs = new EGLConfig[1];
      int[] num_config = new int[1];
      int[] configSpec = {
              EGL10.EGL_NONE
      };
      mEgl.eglChooseConfig(mEglDisplay, configSpec, configs, 1, num_config);
      EGLConfig mEglConfig = configs[0];
      EGLContext mEglContext = mEgl.eglCreateContext(mEglDisplay, mEglConfig,
              EGL10.EGL_NO_CONTEXT, null);
      EGLSurface mEglSurface = null;
      Log.v("HelloAndroid", "M");
      mEglSurface = mEgl.eglCreateWindowSurface(mEglDisplay,
              mEglConfig, surfaceHolder, null);
      Log.v("HelloAndroid", "N");
      mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface,
              mEglContext);
      Log.v("HelloAndroid", "O");
  }
  </code></pre>
  
  <p>The log output I get with platform-tools/adb logcat is:</p>
  
  <pre><code>V/HelloAndroid( 1861): surface.isValid()= false
  D/libEGL  ( 1861): egl.cfg not found, using default config
  D/libEGL  ( 1861): loaded /system/lib/egl/libGLES_android.so
  V/HelloAndroid( 1861): M
  D/AndroidRuntime( 1861): Shutting down VM
  W/dalvikvm( 1861): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
  E/AndroidRuntime( 1861): Uncaught handler: thread main exiting due to uncaught exception
  E/AndroidRuntime( 1861): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.helloandroid/com.example.helloandroid.HelloAndroid}: java.lang.IllegalArgumentException: Make sure the SurfaceView or associated SurfaceHolder has a valid Surface
  E/AndroidRuntime( 1861):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
  </code></pre>
  
  <p>Any help is appreciated.</p>