[Android] OpenGL ES2.0 in onDrawFrame drawing with thread you?

RT, I want to set a thread after each call Thread.sleep unfinished (20 ) to allow the thread to sleep
then continue painting until it is fully completed matrix transformations , to enlarge the animation effect .
but the program has been a crash , so my idea of code impress , seeking Great God Guidelines

  public void onDrawFrame(GL10 gl){
      GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT|GLES20.COLOR_BUFFER_BIT)
      Thread Trans_Thread = new Thread(){
            //zMove用来判定z轴位移量
            float zMove = 0f;
            public void run(){
                 boolean flag = true;
                 while(flag){
                     画四个图标
                     for(int i=0;i<4;i++){
                         //所有矩阵的定义和操作都放在了MatrixState.java里，纯方法实现
                         //矩阵平移，以便图标一字铺开。
                         MatrixState.translate(i*2f,0,0)
                         //被聚焦的图标会有动画放大的效果
                         if(FocusPosition == i){
                                //进行矩阵缩放，即图标缩放
                               MatrixState.scale(1.3f/50,1.3f/50,1.3f/50);
                         }
                         //Square类的绘制函数
                         Square.drawSelf();   
                     }
                     //判定是否已经缩放完成
                     zMove = zMove + 1.3f/50;
                     //运行标志设为false
                     if(zMove>=1.3f) flag = false;
                     try(Thread.sleep(20);)catch(Exception e){System.out.println(e);}
                 }
            }
      }
      Trans_Thread.start();
  }
  

In the absence of additional threads can be stable drawing , but did not focus on the enlarged icon animation .
Great God seek advice
------ Solution --------------------------------- -----------
I think the thread should be placed outside onDrawFrame, then postInvalidate () to inform the system update
------ eference -------- -------------------------------

thanks, buddy, this problem has been solved. Because onDrawFrame function itself is constantly refreshed, as long as the appropriate control parameters can be in it . Your reply this point be rewarded .