Android开发消除横向排列的多个Button之间的空隙

拿RadioButton举例

   <RadioButton                            Android:id="@+id/newregister_rb_nan"                            android:layout_width="wrap_content"                            android:layout_height="match_parent"                            android:checked="true"                            android:background="@null"                //代表把原来自有的边框去掉                            android:button="@drawable/zhuce_anniu"  //代表换成自己要用的图片按钮                            android:layout_marginRight="4dp" />