How to add objects to draw in runtime using GLES20?

In my simple GLES20 app I'm trying to add some objects in runtime to draw. In my Renderer class I have ArrayList of Squares:

private ArrayList<Square> mSquares = new ArrayList<Square>();

Here is my Square class.

Square is drawing well if create it in onSurfaceCreated.

But what I'm actually want to do. I need to add new Square into mSquares in runtime by button clicking and draw squares in onDrawFrame.

In my Renderer class I created AddFigure() method:

public void AddFigure(float x, float y, float z)
{                                                     // color                   coords    angle
    mSquares.add(new Square("Red square", new float[] {1, 0, 0, 1}, new float[] {x, y, z}, 100f));
}

I'm invoking this method by clicking on the button in my Activity:

fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
                mGLRenderer.AddFigure(1f, 1f, 1f);
        }
    });

But it always throwing this exceptions:

E/AndroidRuntime: FATAL EXCEPTION: GLThread 220
    java.util.ConcurrentModificationException

and

E/libEGL: call to OpenGL ES API with no current context (logged once per thread)
E/emuglGLESv2_enc: device/generic/goldfish-opengl/system/GLESv2_enc/GL2Encoder.cpp:s_glEnableVertexAttribArray:741 GL error 0x501
Info: Invalid vertex attribute index. Wanted index: 4294967295. Max index: 16

I'm tried somehow fix it using glBufferData and glBufferSubData, but have no success. Maybe there is an example or wiki how to do it right?

It's ConcurrentModification error, which means you are trying to access the rendering pipeline from a different thread than the OpenGL is rendered on.

This should be the way to do that:

glSurfaceView.queueEvent(new Runnable() {
                    @Override
                    public void run() {
                        mGLRenderer.AddFigure(1f, 1f, 1f);
                    }
                });