SurfaceView isn't valid

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Android

Hi all!
I try to get fullscreen's screenshot in Android. I've found code snippet on internet which do it through openGL. But it doesn't work!
Code snippet:

public class RemoteManager extends Activity {
	
	Bitmap mSavedBM;
	private EGL10 egl;
	private EGLDisplay display;
	private EGLConfig config;
	private EGLSurface surface;
	private EGLContext eglContext;
	private GL11 gl;	
	protected int width, height;
	   
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);    
       
        setContentView(R.layout.main);
     // get the screen width and height
        DisplayMetrics dm = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(dm);
        
        int screenWidth = dm.widthPixels;
        int screenHeight = dm.heightPixels;

        String SCREENSHOT_DIR = "/screenshots";
        
        initGLFr(); //GlView initialized.
        savePixels( 0, 10, screenWidth, screenHeight, gl); //this gets the screen to the mSavedBM.
        saveBitmap(mSavedBM, SCREENSHOT_DIR, "capturedImage");
        //Now we need to save the bitmap (the screen capture) to some location.
        System.out.println("---------already done!!!");
        setContentView(R.layout.main); //This displays the content on the screen
    }
    
    
    private void initGLFr()
    {
    egl = (EGL10) EGLContext.getEGL();
    display = egl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
    int[] ver = new int[2];
    egl.eglInitialize(display, ver);

    int[] configSpec = {EGL10.EGL_NONE};
    EGLConfig[] configOut = new EGLConfig[1];
    int[] nConfig = new int[1];
    egl.eglChooseConfig(display, configSpec, configOut, 1, nConfig);
    config = configOut[0]; 
    eglContext = egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT, null);
    GLSurfaceView surfaceView = new GLSurfaceView(this); 
    SurfaceHolder holder = surfaceView.getHolder(); 
    //////////////// ERROR!!!///////////
    surface = egl.eglCreateWindowSurface(display, config, holder, null);
    ///////////////////////////////////
    egl.eglMakeCurrent(display, surface, surface, eglContext);
    gl = (GL11) eglContext.getGL();
    }
    
    public void savePixels(int x, int y, int w, int h, GL10 gl)
    {
    if (gl == null)
    return;

    synchronized (this) {
    if (mSavedBM != null) {
    mSavedBM.recycle();
    mSavedBM = null;
    }
    }

    int b[] = new int[w * (y + h)];
    int bt[] = new int[w * h];
    IntBuffer ib = IntBuffer.wrap(b);
    ib.position(0);
    gl.glReadPixels(x, 0, w, y + h, GL10.GL_RGBA,GL10.GL_UNSIGNED_BYTE,ib);

    for (int i = 0, k = 0; i < h; i++, k++)
    {
	    //OpenGLbitmap is incompatible with Android bitmap
	    //and so, some corrections need to be done.
	    for (int j = 0; j < w; j++)
	    {
	    int pix = b[i * w + j];
	    int pb = (pix >> 16) & 0xff;
	    int pr = (pix << 16) & 0x00ff0000;
	    int pix1 = (pix & 0xff00ff00) | pr | pb;
	    bt[(h - k - 1) * w + j] = pix1;
	    }
    }

    Bitmap sb = Bitmap.createBitmap(bt, w, h, Bitmap.Config.ARGB_8888);
    synchronized (this)
	    {
	    mSavedBM = sb;
	    }
    }

    static String saveBitmap(Bitmap bitmap, String dir, String baseName) {
    try {
    File sdcard = Environment.getExternalStorageDirectory();
    File pictureDir = new File(sdcard, dir);
    pictureDir.mkdirs();
    File f = null;
    for (int i = 1; i < 200; ++i) {
    String name = baseName + i + ".png";
    f = new File(pictureDir, name);
    if (!f.exists()) {
    break;
    }
    }
    if (!f.exists()) {
    String name = f.getAbsolutePath();
    FileOutputStream fos = new FileOutputStream(name);
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
    fos.flush();
    fos.close();
    return name;
    }
    } catch (Exception e) {

    } finally {

    //if (fos != null) {
    // fos.close();
    // }

    }
    return null;
    } 

The function 'eglCreateWindowSurface' falls down with error!
Error:

09-26 05:05:32.256: ERROR/AndroidRuntime(946): Caused by: java.lang.IllegalArgumentException: Make sure the SurfaceView or associated SurfaceHolder has a valid Surface
09-26 05:05:32.256: ERROR/AndroidRuntime(946):     at com.google.android.gles_jni.EGLImpl._eglCreateWindowSurface(Native Method)
09-26 05:05:32.256: ERROR/AndroidRuntime(946):     at com.google.android.gles_jni.EGLImpl.eglCreateWindowSurface(EGLImpl.java:87)
09-26 05:05:32.256: ERROR/AndroidRuntime(946):     at com.ares.RemoteManager.initGLFr(RemoteManager.java:95)

What do I wrong? Please help me!!!
Sorry for my English!