How to set Full screen dialog with dialog fragment

set this line after creating dialog.

dialog.getWindow().setLayout(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);

If you are creating custom DialogFragment write this in onCreate of your DialogFragment:

setStyle(DialogFragment.STYLE_NORMAL,android.R.style.Theme_Black_NoTitleBar_Fullscreen);

reference

Create theme like this and add to your dialog

<style name="ThemeDialog" parent="android:Theme.Holo.Dialog">
    <item name="android:windowMinWidthMajor">100%</item>
    <item name="android:windowMinWidthMinor">100%</item>
</style>

set this line after creating dialog

getDialog().getWindow()
            .getAttributes().windowAnimations = R.style.ThemeDialog;
    WindowManager.LayoutParams wmlp = getDialog().getWindow().getAttributes();
    wmlp.gravity = Gravity.FILL_HORIZONTAL;
    getDialog().getWindow().setBackgroundDrawable(new ColorDrawable(0));
    getDialog().requestWindowFeature(Window.FEATURE_NO_TITLE);

Create a theme in your style.xml which extends from Theme.AppCompat.Light.DarkActionBar, something like below:

<style name="DialogFragmentTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>

    <item name="android:paddingRight">0dp</item>
    <item name="android:paddingLeft">0dp</item>
    <item name="android:layout_width">match_parent</item>
    <item name="android:windowNoTitle">true</item>
</style>

and set the style you created while opening the dialog, something like below:

CustomDialogFragment mDialog = new CustomDialogFragment();
...
mDialog.setStyle(DialogFragment.STYLE_NORMAL, R.style.DialogFragmentTheme);
mDialog.show(getSupportFragmentManager(), "DialogFragment");