Cannot change the width of AlertDialog with custom view in Android -

i absolute beginner android. having problem setting width of default alertdialog custom view in android. not resizing width of alert dialog. please wrong code ?

this view layout of alert dialog

<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:layout_width="wrap_content"     android:layout_height="match_parent">     <android.support.v7.widget.appcompatbutton         xmlns:app="http://schemas.android.com/apk/res-auto"         android:textcolor="@color/white"         app:backgroundtint="@color/green"         android:layout_gravity="center_horizontal"         android:id="@+id/btn_row_option_done"         android:text="done"         android:layout_width="wrap_content"         android:layout_height="wrap_content" />      <android.support.v7.widget.appcompatbutton         android:textcolor="@color/white"         xmlns:app="http://schemas.android.com/apk/res-auto"         app:backgroundtint="@color/lightblue"         android:layout_gravity="center_horizontal"         android:text="edit"         android:id="@+id/btn_row_option_edit"         android:layout_width="wrap_content"         android:layout_height="wrap_content" />      <android.support.v7.widget.appcompatbutton         android:textcolor="@color/white"         xmlns:app="http://schemas.android.com/apk/res-auto"         app:backgroundtint="@color/red"         android:layout_gravity="center_horizontal"         android:text="delete"         android:id="@+id/btn_row_option_delete"         android:layout_width="wrap_content"         android:layout_height="wrap_content" />      <android.support.v7.widget.appcompatbutton         xmlns:app="http://schemas.android.com/apk/res-auto"         app:backgroundtint="@color/white"         android:layout_gravity="center_horizontal"         android:text="cancel"         android:id="@+id/btn_row_option_cancel"         android:layout_width="wrap_content"         android:layout_height="wrap_content" /> </linearlayout> 

as can see, set width of linearlayout wrap_content.

this how opening alert dialog in java code

public void showoptiondialog(final int id)     {         layoutinflater layoutinflater = layoutinflater.from(getactivity());         view view = layoutinflater.inflate(r.layout.row_option_dialog, null);          final alertdialog alertdialog = new alertdialog.builder(getactivity()).create();         boolean istaskdone = dbhelper.istaskdone(id);         button donebtn = (button)view.findviewbyid(r.id.btn_row_option_done);         if(istaskdone==false)         {             donebtn.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     dbhelper.markasdone(id);                     refreshlistview();                     alertdialog.cancel();                     toast.maketext(getactivity().getbasecontext(),"marked done",toast.length_short).show();                 }             });         }         else{             viewgroup viewgroup = (viewgroup)donebtn.getparent();             viewgroup.removeview(donebtn);         }         button editbtn = (button)view.findviewbyid(r.id.btn_row_option_edit);         if(istaskdone==false)         {             editbtn.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     mainactivity activity = (mainactivity) getactivity();                     activity.replaceedittaskfragment(id);                     alertdialog.cancel();                 }             });         }         else{             viewgroup viewgroup = (viewgroup)editbtn.getparent();             viewgroup.removeview(editbtn);         }         button deletebtn = (button)view.findviewbyid(r.id.btn_row_option_delete);         deletebtn.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 dbhelper.deletetask(id);                 items.remove(optionfocuseditemindex);                 adapter.notifydatasetchanged();                 toast.maketext(getactivity().getbasecontext(),"task deleted",toast.length_short).show();                 alertdialog.cancel();                 updatelistemptytext();             }         });         button cancelbtn = (button)view.findviewbyid(r.id.btn_row_option_cancel);         cancelbtn.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 alertdialog.cancel();             }         });         alertdialog.setview(view);         alertdialog.show();     } 

but when alert dialog opened, width not resized , still showing default size in screenshot.

this screenshot.

as can see, width full of screen did set wrap_content. set 300px. not working. please wrong width code , how can achieve ?

first make other layout container , inside make linear layout wrap content. after can make alpha background of container 0 transparent. dialog inside buttons on inner layout. custom dialog cant use alertdialog, make own activity behavior dialog.