case R.id.btn_3:            Toast my = Toast.makeText(MainActivity.this, "short",                    Toast.LENGTH_SHORT);            //设置显示的位置            my.setGravity(Gravity.CENTER_HORIZONTAL, 60, 40);            //返回视图            LinearLayout lin = (LinearLayout) my.getView();            ImageView img = new ImageView(MainActivity.this);            img.setImageResource(R.drawable.ic_launcher);            //把图片加入到布局里，并且在文字之上            lin.addView(img, 0);            my.show();            break;