android – 如何获得具有有效Surface的SurfaceHolder(EGL.eglCreateWindowSurface需要)？

我尝试用EGL初始化GLES(因为我想从主线程中绘制)
而不是使用渲染器和从onDrawFrame内部绘图).我收到错误：“确保SurfaceView或相关的SurfaceHolder具有有效的Surface”.显然mEgl.eglCreateWindowSurface失败,因为surfaceHolder没有有效的表面.如何获得具有有效Surface的SurfaceHolder？

我的Activity.onCreate方法是：

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,surfaceHolder,null);
    Log.v("HelloAndroid","N");
    mEgl.eglMakeCurrent(mEgldisplay,mEglSurface,mEglContext);
    Log.v("HelloAndroid","O");
}

我使用platform-tools / adb logcat获得的日志输出是：

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)

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解决方法

在创建表面时应该对表面有效的检查.所以,应该在onSurfaceCreated或onSurfaceChanged中调用surface.isValid(),显然,你应该添加surfaceholder.callback