You need to get the current Window and set it’s LayoutParams like so:
Dialog d=new Dialog(mContext);
.........
.........
myDialog.show();
Window window = myDialog.getWindow();
window.setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
Alternative(if above solution does’t works)
In case above code not works well you can use a workaround
styles.xml
<style name="mydialog"></style>
Java
Dialog d=new Dialog(mContext,R.style.mydialog);
.........
.........
myDialog.show();
Window window = myDialog.getWindow();
window.setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);