Android studio 的AlertDialog控件，要实现点击确定和取消按钮时，对话框消失；点击空白处，对话框

builder.setCancelable(false);

下面贴出该属性的定义：

/**
* Sets whether the dialog is cancelable or not.  Default is true.
*
* @return This Builder object to allow for chaining of calls to set methods
*/
public Builder setCancelable(boolean cancelable) {
P.mCancelable = cancelable;
return this;
}