Q:

How to show edges of a cube in OpenGL on Android

I have drawn cubes using OpenGL. Now, I have to show only the edges of that cube. It should look like a cube cage. How can I do this?
My code look likes as follows:
// Each element is a triangle strip of 16 vertices.
            vertices.put(x).put(y).put(zz);
            vertices.put(x).put(y).put(zz);
            vertices.put(xx).put(y).put(zz);
            vertices.put(x).put(yy).put(zz);
            vertices.put(xx).put(yy).put(zz);
            vertices.put(xx).put(yy).put(z);
            vertices.put(xx).put(y).put(zz);
            vertices.put(xx).put(y).put(z);
            vertices.put(x).put(y).put(z);
            vertices.put(xx).put(yy).put(z);
            vertices.put(x).put(yy).put(z);
            vertices.put(x).put(yy).put(zz);
            vertices.put(x).put(y).put(z);
            vertices.put(x).put(y).put(zz);
            vertices.put(xx).put(y).put(zz);
            vertices.put(xx).put(y).put(zz);

            int color = Color.GRAY; 
            for ( int j = 0; j < 16; ++j ) 
            {
                colors.put(color);
            }  
                   vertices.position(0);
                   colors.position(0);

A:

You will have to draw the lines defining the edges of the cube with the GL_LINES primitive.

