代码中修改组件的margin属性

LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(

                        ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

                layoutParams.setMargins(0, 0, 0, 0);// 4个参数按顺序分别是左上右下

                Btn1.setLayoutParams(layoutParams);