Drawing Simple Primitives with OpenGL ES I [en]

import java.nio.*;

public void onSurfaceCreated(GL10 gl, EGLConfig config)
	{
	    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
	    gl.glLineWidth(2);
 
	    ByteBuffer vbb = ByteBuffer.allocateDirect(4 * Float.SIZE * 2);
	    vbb.order(ByteOrder.nativeOrder());
	    _vertexBuffer = vbb.asFloatBuffer();
 
	    float[] fv = { 50, 50,
	    		      -50, 50,
	    		      -50, -50,
	    		      50, -50 };
	    _vertexBuffer.put(fv);
 
	    vbb = ByteBuffer.allocateDirect(4 * Short.SIZE);
	    vbb.order(ByteOrder.nativeOrder());
	    _indexBuffer = vbb.asShortBuffer();
 
	    short[] sv = { 0, 1, 2, 3 };
	    _indexBuffer.put(sv);
 
	    _vertexBuffer.position(0);
	    _indexBuffer.position(0);
 
	}

	     // set the drawing colour
	     gl.glColor4f(1.0f, 0.0f, 0.0f, 1.0f);
 
	     gl.glVertexPointer(2, GL10.GL_FLOAT, 0, _vertexBuffer);
	     gl.glDrawElements(GL10.GL_LINES, 4, GL10.GL_UNSIGNED_SHORT, _indexBuffer);