的ExceptionInInitializerError

Question

I'm trying to initialize GL11 because i was having troubling referencing a method that had

GL11 gl 

as its argument. I tried to initialize it in my renderer class but it didn't work so I figured that it the initialization was messing with the renderer and created a new class to initialize in.

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.opengles.GL11;

import android.opengl.GLU;



public class Unproject {

public static float setx;
public static float sety;
public static float posx, posy, posz;

EGLConfig[] configs = new EGLConfig[1];
EGLConfig config = configs[0];
static EGLContext glContext; 
public static GL11 gl = (GL11)glContext.getGL();
EGLDisplay dpy =  ((EGL10) gl).eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);

public Unproject() {
    glContext = ((EGL10) gl).eglCreateContext(dpy, config, EGL10.EGL_NO_CONTEXT, null);
}

    public static void vector3 (GL11 gl){

        int[] viewport = new int[4];
        float[] modelview = new float[16];
        float[] projection = new float[16];
        float winx, winy, winz;
        float[] newcoords = new float[3];

        gl.glGetIntegerv(GL11.GL_VIEWPORT, viewport, 0);
        gl.glGetFloatv(GL11.GL_MODELVIEW_MATRIX, modelview, 0);
        gl.glGetFloatv(GL11.GL_PROJECTION_MATRIX, projection, 0);

        winx = (float)setx;
        winy = (float)viewport[3] - sety;
        winz = 0;

        GLU.gluUnProject(winx, winy, winz, modelview, 0, projection, 0, viewport, 0, newcoords, 0);
        posx = (int)newcoords[1];
        posy = (int)newcoords[2];
        posz = (int)newcoords[3];


    }
}

Vector3 is the method I was having trouble with. I moved it here into this class from the renderer.

Here is my renderer:

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import javax.microedition.khronos.opengles.GL11;


import android.opengl.GLU;
import android.opengl.GLSurfaceView.Renderer;
import android.view.MotionEvent;


public class GLSurfaceRenderer implements Renderer{


public float setx, sety;
private float posx, posy, posz;
private double speed;
private static float rotation;
private static float statrotation;

GL11 gl; 



private static FlatColoredSquare square;
private static FlatColoredSquare statSquare;



    public GLSurfaceRenderer () {

    square = new FlatColoredSquare();
    statSquare = new FlatColoredSquare();
    rotation = (float) Math.floor(Math.random()*361);
    speed = 0.1;    

}
    public synchronized void randomMethod(MotionEvent event){
        if (event.getAction() == MotionEvent.ACTION_DOWN){
        setx = event.getX();
        sety = event.getY();
        Unproject.vector3(gl);
        }
    }   

@Override
public void onDrawFrame(GL10 gl) {
         gl.glClear(GL10.GL_COLOR_BUFFER_BIT |
            GL10.GL_DEPTH_BUFFER_BIT);
    gl.glLoadIdentity();
    gl.glScalef(10, 10, 0);
    gl.glPushMatrix();
    gl.glRotatef(rotation, 0, 0, 1);
    gl.glTranslatef((float) speed/10, 0, 0);    
    square.draw(gl);    
    gl.glPopMatrix();

    gl.glPushMatrix();
    gl.glTranslatef(posx, posy, posz);
    gl.glRotatef(statrotation,0,0,1);
    statSquare.draw(gl);
    gl.glPopMatrix();


    statrotation++;
    speed++;    

}   





@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
    gl.glViewport(0, 0, width, height);
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();
    GLU.gluOrtho2D(gl, 0.0f, width, 0.0f, height);
    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glLoadIdentity();

}

@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
    gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    gl.glShadeModel(GL10.GL_SMOOTH);
    gl.glClearDepthf(1.0f);
    gl.glEnable(GL10.GL_DEPTH_TEST);
    gl.glDepthFunc(GL10.GL_LEQUAL);
    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);

}



}

Unfortuanatly this code throws an ExceptionInInitializerError

08-01 17:01:34.672: ERROR/AndroidRuntime(421): Uncaught handler: thread main exiting due to uncaught exception
08-01 17:01:34.762: ERROR/AndroidRuntime(421): java.lang.ExceptionInInitializerError
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.app.ui.GLSurfaceRenderer.randomMethod(GLSurfaceRenderer.java:44)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.app.ui.Practice.onTouchEvent(Practice.java:37)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.app.Activity.dispatchTouchEvent(Activity.java:2064)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1690)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.os.Looper.loop(Looper.java:123)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.app.ActivityThread.main(ActivityThread.java:4310)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at java.lang.reflect.Method.invokeNative(Native Method)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at java.lang.reflect.Method.invoke(Method.java:521)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at dalvik.system.NativeStart.main(Native Method)
08-01 17:01:34.762: ERROR/AndroidRuntime(421): Caused by: java.lang.NullPointerException
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     at android.app.ui.Unproject.<clinit>(Unproject.java:22)
08-01 17:01:34.762: ERROR/AndroidRuntime(421):     ... 13 more

Is there anything I can do to correct this? Am I completely up the wrong tree? I think it might be the way that I'm sharing variables between classes, is there a better way to do that?

Answer 1

Based on this documentation An ExceptionInInitializerError is thrown to indicate that an exception occurred during evaluation of a static initializer or the initializer for a static variable. Check your code has any static initialization logic.

Answer 2

It appears that the error you are getting is because of a NullPointerException in your class initialization.

static EGLContext glContext; 
public static GL11 gl = (GL11)glContext.getGL();

You will notice you are attempting to call getGl() from an instance of EGLContext which isn't initialized. You will need to first assign glContext to something before you can use it.

The stacktrace mentions <clinit> , which isn't very helpful if you don't know what it means. It is referencing class initialization, which is what happens when static members are initialized (as in this case), but it could also reference a static initialization block that looks like this:

static {
    //some static init code
}

The reason that ExceptionInInitializerError is throw is likely because something higher up is catching all Exceptions, and wrapping them in the ExceptionInInitializerError .